Re: Topband: Inverted-L question

[Guy Olinger K2AV]

Hi Steve,

5300 pF is way large. It indicates *something *else is going on.
"Something" needs to be determined.

One thing for sure, after nearly a decade of correspondence with this as a
frequent subject, there is no one single "silver bullet" to fix this in all
cases. It is complicated and with several distinctly different causes, each
one by itself capable of causing the symptoms you report. Only *one *of the
several causes is* not* also causing significant RF loss that minimizes
your radiated TX power.

Worse, quite often two or three of them are in effect at the same time. And
excellent reports and suggestions by those trying to help out seem like an
argument about which solution is "the one". In fact, all of the respondents
may be making an excellent suggestion about *one *of the* several ways* the
problem reported above can be caused.

Very unfortunately, one may have to fix all two or three or four to get the
antenna acting with an ideal modeled result.

*So, apologies for the length*, but this one possibly takes a silver
bullet, plus a gold bullet, plus a platinum bullet, plus a depleted uranium
bullet to solve all the possibles responsible for this report. So on to the
stuff

The *large* capacitor needed means that the amount of inductive X being
tuned out *is getting small.* If what you did was lengthen the Inv L
horizontal to get 50Ω R and then use a series capacitor to tune out the
inductive X, the method has a blind spot where the* inductive reactance at
R=50Ω is so low that the cap has to be huge. *

This is usually caused with an Inv L because there is* a lot of **fixed RF
loss R somewhere* added to the L's natural 20-35Ω radiation R at X=0Ω. The
Inv L is decidedly not a natural 50Ω antenna. X=0Ω should not be close to
R=50Ω

If you take away the added loss, the now needed extra length to get R=50Ω
all from radiation resistance (lengthening the horizontal) is substantial.
The longer length has a lot larger inductive X to tune out. This *reduces *the
size of the cap needed. *Smaller *pF value caps produce the *larger
*capacitive reactance
to cancel out that larger inductive X.

And of course it could be that something in the environment is giving you
an "X push" one way or the other.

So exactly *what *is the added RF loss, or X push, and *what *is causing
it?

To start, you have an *undefined* tower involvement which is capable of
producing a very large RF loss addition to that tower-supported 1/4
wave-ish L, *and at the same time *also capable of producing a very large X
push in a capacitive *or *inductive direction.

Anything in the k2av.com "Loss List"
 could
be adding ohms to the feedpoint R.

One of the splendidly frustrating things about 160 meter antennas is,
unless we can put up a 160 dipole at 250', we probably need to go vertical
oriented.

We can't do problem-solving on vertical-antennas-for-160 accurately or
effectively without considering several overwhelming factors on 160: Loss,
ground effects, and a monstrous wavelength which multiplies miscellaneous
conductor involvement.

These can't be reliably determined or solved by tuning for SWR. You're only
trying to match* (antenna + problems)* to 50Ω.

The inverted L with the bend supported by the tower, and fed at the
radials, is really a transformer in disguise. *The L is one winding of the
"transformer". The tower and each coax shield and control conductor on the
tower are separate windings in this multi-winding ad-hoc "transformer".*

Somewhere in my stuff I have a NEC 4 model of an L supported at the bend by
a tower that has more induced current in the tower than there is in the L.
This transformer situation has an *effective *turns ratio that keeps the
tower with lower voltage and higher current. This higher current is then
driven into and dissipated in the ground.

If your tower cabling has:

All its shields and unused conductors in the cable grounded to the tower at
the base...

And all active control conductors bypassed to the tower at the base…

Then Tree's suggestion to detune the tower works to its maximum
effectiveness.

But tower detuning has to be done well. Otherwise the induction to the
tower will still drive a lot of current into the ground. The induced RF
current in ungrounded or unbypassed coax shields and control conductors
will be driven into ground via capacity effect all along their lengths
laying on or buried in the ground between the tower and the shack This loss
adds to the R of the L feed through the above transformer effect.

A second issue is whether the radial's center is solidly connected to the
tower's cable grounding point. That will substantially reduce the dirt's R
that the induction is forcing RF into.

One case I was involved in violently changed the feed Z when the tower base
was bonded to the radial feed. The performance picked up substantially and
he only needed a 5:4 turns ratio transformer to get close to 50 ohms after
pruning the L for X=0. Until 

Re: Topband: 160 Retirement VO1HP

[Guy Olinger K2AV]

Well, for a long time, a 160 test was not complete without VO1HP in the
log. But I certainly do understand the WX and related strains up there. My
brother lived in St Johns for a while. One of my nieces is a “Newfie”.
 (She lives in Atlanta burbs now. )

Frank was a contributor in the early days getting FCP going. Particularly
in solutions to support L’s bend with a tower.

Good luck Frank. See you on 80m.

73, Guy K2AV

On Tue, Sep 12, 2023 at 3:46 PM Frank  wrote:

> The time has come to downsize my operations. I  thought I would let my
> Topband friends know that I have retired from 160M and will not appear on
> the band this season.  Yesterday I took down my lowband tower which
> supported an inverted L and FCP at my remote site.  The  "L" has been
> coiled and ready to pass on to a younger addict!  I thank Guy K2AV for his
> development work on the Folded Counterpoise. The FCP has proven to be very
> effective for me.
>
>  I have 77 turns on my coil and will not have to worry about the 100kmph+
> winds, snows and ice of our Newfoundland winter,  battering away at my
> overhead wires. I have 238 DXCC confirmed and have thoroughly enjoyed 160M
> since my first QSO with Bob Kavanaugh VE1AXT in 1974. (Recently SK VE3OSZ)
> There was one interruption of about 10 years in the 1980's when family and
> professional duties combined with a lack of real estate kept me off the
> band.
>
> My forward focus will be on completion of 5BWAZ.  I need 4 Zones on 80M and
> Zone 23 on 10M.
>
> All the best to you Topbanders!
>
> 73
> Frank VO1HP
>
>
> <
> https://www.avast.com/sig-email?utm_medium=email_source=link_campaign=sig-email_content=webmail
> >
> Virus-free.www.avast.com
> <
> https://www.avast.com/sig-email?utm_medium=email_source=link_campaign=sig-email_content=webmail
> >
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Topband: Upgrades to k2av.com

[Guy Olinger K2AV]

After a long medical issues delay, many upgrades to k2av.com are
completed and uploaded. In it we have addressed some number of issues
brought up in correspondence. Enjoy  :>)

73, Guy K2AV

=

Revisions Listing for k2av.com

V.2023.09.20

[All Articles] To support our international readers, historically 55%
of our readership, we have added a no-frame mode with a link-based
index with brief descriptions. This supports auto-translators embedded
in several popular browsers which no longer translate frame content.
>From k2av.com, you can access no-frame mode with the top left button
on the home page. The left margin green button index is omitted in the
no-frame mode. No-frame mode can be accessed directly with
k2av.com/NoFrameIndex.html, case-sensitive. The no-frame index has a
link which opens the home page in no-frame mode. The no-frame index
also includes brief article descriptions.

[Design Inverted L] [Place Inverted L] These two articles were
combined to reduce much duplicated material, place dependent materials
next to each other and improve reading flow. Old names are preserved
in the new html, linking directly to the new article content to keep
from breaking old direct external links saved by readers.

[Design/Place an Inverted L] This article addresses a decade's worth
of various issues and information proven to be important designing and
implementing an L at various installer's sites. The article has been
broken into sections and subsections with a descriptive index at the
head of the article.

[Design/Place an Inverted L] The new article contains an index to its
content. This addresses a common complaint: Needing to read the entire
long article from beginning to end to find something previously read.
Each index item contains a short description and a direct link to each
section and subsection of the article. Article content can also be
read sequentially without using the index, beginning just below the
index.

Previous large subsections were broken up into multiple subsections.
Subsections are restricted to a limited number of short to medium
paragraphs. We hope the article's index will help a reader to return
later to a point of interest.

The entire index to can be read as text to get a quick understanding
of the range of issues that can affect installing an excellent L/FCP.

[Design/Place an Inverted L] content for hillside placements of L/FCP
is deferred, needing illustrations, and research to deal with
conflicting modeling results and the inability to enter this terrain
directly into EZNEC. This does not refer to "gradual slopes". The
listings are retained with a note.

[Illustrated articles] For the benefit of those using translators,
text embedded as graphics in .PNG and .GIF illustrations is repeated
separately in HTML text so that auto-translators are aware of it. Look
for translated illustration text in a box immediately after
illustrations. These graphics text HTML repeats will be added
gradually as time permits, without notice or version renumbering.

[Many articles] Readability Improvements and Clarifications after a
one year, four month hiatus. Due to various family medical issues this
work was necessarily set aside, leaving much to be done later. Many
thanks for readers' patience on delayed answers to correspondence.

==
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Re: Topband: CW rhythm, swing, speed

[Guy Olinger K2AV]

I always liked W4KFC on a bug. It was very recognizable, but it was not
excessive. Like watching someone walk who has added just a hint of dance
steps.

73, Guy K2AV

On Sun, Jun 25, 2023 at 8:42 AM Mike Waters  wrote:

> On Sun, Jun 25, 2023, 5:42 AM Michael Rutkaus  wrote:
>
> > ... most of the time
> > had a friendly "swing" to his sending, it sounded like a casual friendly
> > conversation.  And Kay's CW was friendly and precise.
> >
>
> Sounds like he had a Vibroplex "bug"? Reading back through old QSTs in the
> monthly letters column, many correspondents strongly disliked that swing. I
> didn't care one way or the other; however, I always tried to send
> electronic keyer quality CW.  :-)
>
> 73 Mike
> W0BTU
>
> >
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Re: Topband: Stew Perry Topband Challenge

[Guy Olinger K2AV]

That was a really attenuated contest.

VE3MGY was weak all night. Except VE3MGY is *never *weak here unless the
sun hasn't gone down. Best proof of a weird, attenuated night. I only
worked 5 VE's, none of them loud, and normally work 20+, even in summer at
least in high teens. Not this year

Never managed to copy a European, much less work one. I did a couple of
times hear a station calling me that had "5K" in the call sign. So far in
Tree's listing PA5KT and EI5KF are the only call signs with a "5K" in
them. Probably was Gerald. Path to him would have least amount of sunlight,
farthest west.

Worked ONE USA west coast, K7RAT, also my longest QSO. Struggle to work
anything west of Mississippi.

About half my QSO's needed repeats. Sorry about that.

QSB was deep and fast, seemingly on everything past 500 miles or so. QRN
was awful and coming from every direction.

Definitely weird. Wonder if this will be the way of summer Topband until
the sunspots go down again.

73, Guy K2AV





On Tue, Jun 20, 2023 at 7:22 AM Henk Remijn PA5KT via Topband <
topband@contesting.com> wrote:

> I was cq-ing between 0100Z and sunrise. Did not work any NA. Was spotted
> 6 times by W1NT-6.
>
> Was also active in the evening, but 6m did win over 160m, so spent most
> time on 6m.
>
> Worked 23 stations, only EU.
>
> I did hear some NA stations, but impossible to copy callsigns.
>
> 73 Henk PA5KT
>
> Op 19-6-2023 om 11:14 schreef Roger Kennedy:
> > Well I don't know how others got on . . .
> >
> > But I didn't hear one single North American station on Saturday night !
> >
> > Roger G3YRO
> >
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
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>
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Topband: 160 ain't dead yet.

[Guy Olinger K2AV]

Amazing 10 and 15 meters in ARRL DX. Also...

2340Z 22 Feb 2023.  G3YRO heard at 1.827.0 and copied call 339. Called but
no joy. He might have heard me, but no two-way. No QRN, blizzard in most of
US.

We just assume that 160 is *dead* when 10 is wide open. 160 ain't dead, but
not sure what it is. This will be the first sunspot max, when we have
worldwide RBN, the internet, and lots of rigs with K3 level RX performance.

We shall see.

Now's when a few dB makes a big difference.

In the meantime I have to get my 20-6m stuff working.

Is this one going to be like 1958?

Back then we LITERALLY worked Los Angeles CA from Columbus, OH on 10m with
a 75A3, & Johnson Ranger loaded into a 2 foot salty wet noodle. That was
after using radiator, bed springs, sink trap, a metal door and a copper
window screen as an antenna. School buddy's dad had a ham station, my first
exposure to ham radio. I was hooked. Probably was the power cord radiating,
but we didn't know that and it was great fun. (It did dry up the noodle.)

Anyhow, we need to see what MF propagation *really* is at solar max.

73, Guy K2AV
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Re: Topband: Radials, EZNEC and far field

[Guy Olinger K2AV]

Hi Charlie.

Naw, it's also the same if you hang it on a long strap or simply set it
down on the sand. The incoming distant signal is simply diminished at that
point. The essential modifying aspect is how much sand between you and the
water's edge. I'm sure it has a ghastly complex explanation.

What is not in doubt is the considerably increased strength of over-water
signals at the water's edge.

On Tue, Dec 20, 2022 at 6:17 PM  wrote:

> >Having walked around on the beach with a battery K2 listening to incoming
> signals on a short antenna, walking 50 feet from the water drops signals
> multiple S units."
>
> Perhaps the handheld radio has a better ground connection, capacity coupled
> or not, through you and into the salt water + sand at the beach.  Then,
> walking away from the beach
> that connection is greatly diminished.
>
> 73,
> Charlie, N0TT
>
> On Tue, 20 Dec 2022 08:58:23 -0500 Guy Olinger K2AV 
> writes:
> > Having walked around on the beach with a battery K2 listening to
> > incoming
> > signals on a short antenna, walking 50 feet from the water drops
> > signals
> > multiple S units. Over the beach there is an absorption zone
> > starting at
> > the sand at water’s edge which goes higher and higher the farther
> > from the
> > water. This isn’t EZNEC, just observation on Core Banks, NC during
> > a number
> > of IOTA contests. Very easy with all those signals to hear what was
> > going
> > on.
> >
> > On 40m there was a big difference between a doublet at 40’ and
> > 50’, back
> > from the beach about 200’.
> >
> > Apparently sand wetted with salt water is quite lossy.
> >
> > But even not optimal at the beach smacks the snot out inland
> > locations.
> > Which IMHO explains the wide variety of beach-based reports.
> >
> > Also a very short vertical radiator away from water’s edge will
> > not hear as
> > much as a tall one as the tall wire has more intercept outside the
> > absorption zone next to the sand.
> >
> > It’s really quite a complex subject.
> >
> > 73, Guy K2AV
> >
> > On Tue, Dec 20, 2022 at 7:28 AM  wrote:
> >
> > > Hi Frank
> > >
> > > You wrote " .  A vertical over a salt marsh or within about a
> > wavelength of
> > > salt water will produce
> > > 6 dB or more of gain at low angles compared to a vertical with
> > poorly
> > > conducting soil in its reflection zone
> > > "
> > >
> > > The assumption that "next to the water" is the same as "in the
> > water" , is
> > > a
> > > not right.  It is not the same !
> > >
> > > I listen to George signal with vertical "in the water " and the 10
> > db
> > > difference in signal is real.  Moving the antenna on the beach and
> > you lose
> > > 10 db or even more on practice, not on paper.
> > >
> > > I see that on my S  meter more than a dozen times.
> > >
> > > George has a vertical on his house in Miami, the ground plane is
> > just a
> > > plate down the water. The vertical is made with fiberglass pole
> > 18m high.
> > > My
> > > antenna is a full size vertical with a good radial system over the
> > > Everglade
> > > land, if I dig 2 Ft I have water from the Everglade underground
> > river.
> > >
> > > George can run a pile up from Europe with 10W, I can keep up with
> > him
> > > running legal limit power. We are talking about 160m only.
> > >
> > > 73's
> > > JC
> > > N4IS
> > >
> > > _
> > > Searchable Archives: http://www.contesting.com/_topband - Topband
> > > Reflector
> > >
> > --
> > Sent via Gmail Mobile on my iPhone
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> > Reflector
> >
>
>
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Re: Topband: Radials, EZNEC and far field

[Guy Olinger K2AV]

Having walked around on the beach with a battery K2 listening to incoming
signals on a short antenna, walking 50 feet from the water drops signals
multiple S units. Over the beach there is an absorption zone starting at
the sand at water’s edge which goes higher and higher the farther from the
water. This isn’t EZNEC, just observation on Core Banks, NC during a number
of IOTA contests. Very easy with all those signals to hear what was going
on.

On 40m there was a big difference between a doublet at 40’ and 50’, back
from the beach about 200’.

Apparently sand wetted with salt water is quite lossy.

But even not optimal at the beach smacks the snot out inland locations.
Which IMHO explains the wide variety of beach-based reports.

Also a very short vertical radiator away from water’s edge will not hear as
much as a tall one as the tall wire has more intercept outside the
absorption zone next to the sand.

It’s really quite a complex subject.

73, Guy K2AV

On Tue, Dec 20, 2022 at 7:28 AM  wrote:

> Hi Frank
>
> You wrote " .  A vertical over a salt marsh or within about a wavelength of
> salt water will produce
> 6 dB or more of gain at low angles compared to a vertical with poorly
> conducting soil in its reflection zone
> "
>
> The assumption that "next to the water" is the same as "in the water" , is
> a
> not right.  It is not the same !
>
> I listen to George signal with vertical "in the water " and the 10 db
> difference in signal is real.  Moving the antenna on the beach and you lose
> 10 db or even more on practice, not on paper.
>
> I see that on my S  meter more than a dozen times.
>
> George has a vertical on his house in Miami, the ground plane is just a
> plate down the water. The vertical is made with fiberglass pole 18m high.
> My
> antenna is a full size vertical with a good radial system over the
> Everglade
> land, if I dig 2 Ft I have water from the Everglade underground river.
>
> George can run a pile up from Europe with 10W, I can keep up with him
> running legal limit power. We are talking about 160m only.
>
> 73's
> JC
> N4IS
>
> _
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> Reflector
>
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Re: Topband: loop on ground vs beverage

[Guy Olinger K2AV]

Hi Andy,

One thing I noticed listening, was an apparent lack of gain or noise
equalization between the two antennas. Either that or the LOG is WAY
quieter than the beverage. Adding an amplifier to an RX antenna, preferably
out at the antenna IS a bit of a pain, and needs careful work with a signal
source to get right, providing the only way to see exactly is going on.
Sometimes gain equalization shows one antenna as significantly better in a
given direction, or can reveal that an amplifier out at the antenna was
what was needed, not a new antenna.

LOGs and BOGs are lossy RX antennas and generally could use an amp.

One thing about LOGs is that they need to be modeled to account for the
severe velocity factor (VF) changes possible when laying on the ground. The
actual pattern can vary considerably depending on VF, and LOG patterns are
not at all intuitive. To figure out the modeling, you have to measure DOGs
to "tunej" the model., that is set the model's ground constants and wire
height above ground to match what you are getting with the DOG. There is no
cookie cutter size that fits all.

A while back, here in North Carolina, a brave band of locals went on a VF
study around the region to try and help explain the widely varying behavior
and effectiveness of BOG's. Measured VF's of DOG (dipole on ground) wires
laid on the ground varied from 45% to 85%, R at X=0 between 80 and 200. We
sometimes measured wild variations between various spots on the same single
piece of property, even after verifying no buried conductors. In a few
cases, we observed wide variation between N-S and E-W DOGs that had a
common center point.

Wide variation over time was seen with dry periods vs. wet, covered by snow
in winter, with and without accumulated seasons of falling leaf cover, laid
on grass vs. notched through the grass down to the dirt, laid on unmowed
grass during the growing season, vs. same during late fall and winter, laid
upon old leaf cover vs notched down to earth.

In the end the only way to size a 160 BOG was to lay down a DOG in the same
exact place and placement method as the intended BOG. Trim the DOG to get a
resonance (X = 0 ohms, not minimum SWR) at 1.140 MHz, and without moving
the dog wire, connect the wires at center and add the stuff at the ends to
turn it into a BOG. Those worked very well until the variations above set
in. Particularly falling leaves then becoming wet.

I had phased LOGS on Europe here, with all the issues above paid attention
to, including all the tuning falderal to get them to correctly phase. At
the start they were wonderful, but started to drift toward mediocre and
worse. Experience
was that they had to be retuned several times a year for rearward null, and
being under leaves basically shut them off. This necessitated blowing
leaves off the wires. A serious accumulation of snow degraded performance.
The best thing was to retune them before a contest.

AT some point other household issues controlled and the loops were retired
in place. And then the FCP thing started, soaking up all available time.

Those who live in the desert would be able to put LOGs down, tune them up
and keep them, unless it rained. Otherwise, especially if one's property is
heavily wooded, one has a cranky set of problems that go along with LOGs.

Good luck with it and 73,

Guy K2AV












On Thu, Nov 17, 2022 at 6:38 PM Andree DL8LAS via Topband <
topband@contesting.com> wrote:

>  Hey,
> today a very nice receiving test and result.I compared my 80m long LOG
> direct on ground  in a circle  with my858 ft long beverage to JA.Dietmar
> HS0ZFV on 160m CW...
>
> https://www.youtube.com/watch?v=AnPnXuV0XmA
> 73, Andy DL8LAS
>
> www.dl8las.com
> www.swing-company-bigband.de/
> www.uni-big-band-kiel.de/
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> Reflector
>
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Re: Topband: Poor 160m DX Propagation

[Guy Olinger K2AV]

Just looking around the band tonight, and what I'm hearing is pretty
representative of what's been going on.

1) The general propagation is down about what one would historically expect
at this point in the sunspot cycle. We're gonna put up with that for
several years.

2) The propagation seems about right for April, it will get worse because
it's moving toward summer.

3) QRN is getting worse and worse and worse. I can remember in 1958, 59,
deep into 80m NTS traffic nets and having to put up with QRN for 2, 3
months in summer, and now and then having to QSY to 40m for a path
diminished by low power, low antenna, poor antenna, etc. The other 9 months
were QRN free, or QRN spread out so much, not bad enough to bother.

Today, 02Z on 24 April, QRN is coming from a string of thunderstorms,
having a look at Blitzortung.org, that stretch all the way from the Texas
Panhandle to Manitoba.

In late March, there was a string of thunderstorms off the east coast out
about 100-200 miles all the way from Georgia to New Brunswick. It ran all
night without any pause, never cooling off and was still there long after
the sun was up, finally gone the next day after another night.

If you are in Europe using CW and you do not have an EXCELLENT transmit
antenna, running power, I won't hear a peep from you, for sure not until
the QRN dies down, and still likely not, because 1) and 2) above are about
normal for sunspots and seasons. FT8, with the gain in demodulation, and
its organizational advantages, may still make it.

The size and persistence of the QRN storms are steadily increasing, on a
ramp since the 60's, and with the increase absolutely NOT slowing down. We
have this undiminished problem with global average atmospheric energy
increase (also known as climate change and global warming). The size of
storm circulation patterns around low pressure systems has become large
enough to most commonly cover half of the continental US. The increase in
atmospheric energy due to heat retention supplies the energy to push
the circulation out that far.

When I was in college, those patterns would commonly be four, five or six
discrete circulations. Now we are perilously close to creating a
hemispheric low pressure circulation that goes West to East in Mexico and
East to west over the Arctic Ocean. Think that one will have QRN in the
springtime?

Let's not be beating up on folks that are having a hard time hearing on 160
about now. Far worse problems afoot.

I still listen and hear "openings" scattered around among the
disadvantages, kind of like clear patches in a mostly cloudy sky. But I
have neither time nor stamina any more to listen in the wee hours to see IF
someone MIGHT be sending CQ on CW. At least (and primarily) FT8 is all in
one place and can drive a computer which can sound an alarm and get my
attention. I'm not saying I love FT8 more than my faithful love CW. Not at
all. But noting what and how FT8.

Why outside of contests do we do our CW calling all over the place? Then I
have to go tune in from the P3 display, maybe turn on my K3's APF to copy,
and the CQ call disappears before I figure out who it was.

Why not do non-contest CQ's all on exactly 1825.000, 1825.333 1825.667,
1826.000, 1826.333. Region 1 at the hour:00 plus multiples of 3 minutes,
Region 2 at the hour:01 plus multiples of 3 minutes. Region 3 at the
hour:02 plus multiples of 3 minutes. No transmitting on the calling
frequencies outside of your region's one minute slot. Never, Ever.

Then I can listen on CW using SSB mode to **all 5** calling frequencies at
once, using my 2.7 kHz SSB filter, which will allow me to hear peeps, even
if too weak for copy. Then I look at my watch to see if that is EU or the
Americas, and switch from SSB to CW and the narrow filter, and tune to
where the peep is coming from.

Contact made, then any exchange other than one of either true RST (5n9) or
dB above noise (B15) , or true dB microvolts (nnM for plus dB, Mnn for
minus dB), S units (Sn or S9/nn for dB over S9).

Always go down or up in multiples of 3 kHz for locations, names, rigs,
antennas, ragchew, etc.. The QSY instruction or request is U3, U6, D3, D6,
etc sent 3 times rapidly. Folks will get used to listening on the QSY spots
to know that U3 U6 K3 or D6 from your calling frequency is busy.
Or better.

Set my P3 to 1826.000, with span set to 15 kHz. Then I can see what is
busy. OK to call stations after prior extended QSO on U/D frequency only.

And if your selectivity won't stand another station up/down 333 Hz, you
need to get a modern receiver or a filter and it's good practice for the CW
contests which WILL force you to deal with 300-400 Hz spacing.

And if a DX station has established a run on a down QSY, when you see a
50D9 on the spot you know that's 1825.000 down 9 kHz, he's outside the +/-
3,6 frequencies, he's on 1816 and pileups should stay between up .5 and up
1.5. 56U12 means he's up on 1837.667 and his pileup is up .5 to up 1.5.

Otherwise, if we 

Re: Topband: High winds flapping the L/FCP

[Guy Olinger K2AV]

Had another gusty day, ran more (120) graphing cycles for a longer time (40
minutes) to see if the additional time showed more variation. It did. This
one explained some never explained KPA1500 SWR faults. Added that to the
Snip.

k2av.com/Snips.20220323.html

73, Guy K2AV


On Wed, Mar 23, 2022 at 11:48 PM Guy Olinger K2AV 
wrote:
>
> Had a very gusty March 7 here in eastern North Carolina blowing the
> L/FCP all over. Did some 160m R,X,SWR scans to see the electrical
> result of that, recording them to graphical format. Was not expecting
> what I got.
>
> Would you have guessed that there is a way for the wind to wobble an
> antenna wire, so that the feed X would wobble, the feed SWR wobble
> worse, and the feed R would not? Text and graphics at:
>
> k2av.com/Snips.20220323.html
>
> Snips are a new format on k2av.com so I can post to list-servers using
> short messages with a link  without loading the list with
> illustrations or detailed text, and save pix and text in an accessible
> place where people can get to them without having to dig through
> archives. Then I can post with careful language, illustrations, keep
> them indexed and available and *editable* on the web site for later
> readers.
>
> A short format for curiosities, oddities, new understandings, answers
> to posts on list-servers, etc.
>
> Enjoy.
>
> 73, Guy K2AV
-- 
Sent via Gmail Mobile on my iPhone
_
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Topband: High winds flapping the L/FCP

[Guy Olinger K2AV]

Had a very gusty March 7 here in eastern North Carolina blowing the
L/FCP all over. Did some 160m R,X,SWR scans to see the electrical
result of that, recording them to graphical format. Was not expecting
what I got.

Would you have guessed that there is a way for the wind to wobble an
antenna wire, so that the feed X would wobble, the feed SWR wobble
worse, and the feed R would not? Text and graphics at:

k2av.com/Snips.20220323.html

Snips are a new format on k2av.com so I can post to list-servers using
short messages with a link  without loading the list with
illustrations or detailed text, and save pix and text in an accessible
place where people can get to them without having to dig through
archives. Then I can post with careful language, illustrations, keep
them indexed and available and *editable* on the web site for later
readers.

A short format for curiosities, oddities, new understandings, answers
to posts on list-servers, etc.

Enjoy.

73, Guy K2AV
_
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Topband: k2av.com new material in V.2022.01.15

[Guy Olinger K2AV]

Version 2022.01.15 of k2av.com is up. Current release "Versions" content:

*V.2022.01.15*
- [Home Page] In "Very Useful Details" added item (n) referencing and
linking to added content in "Taming the Inverted L": Using a special jumper
to eliminate false readings sometimes experienced measuring at the
Isolation Transformer. Sneaky problem not limited to inverted L's, FCP's,
or IsoT's.
- [Various] For situations needing common mode chokes, direct users to
K9YC's most recent designs. Added references and links to K9YC's 2018
reference PDF: *"A New Choke Cookbook for the 160–10M Bands, Using
Fair-Rite #31 2.4-in o.d. (2631803802) and 4-in o.d. (2631814002) Toroids".*
- [Field Adjustable IsoT] New article details winding a robust
*field-adjustable* step-up isolation transformer to deal with isolating and
matching an L/FCP feed R's 23-39Ω or 27-46Ω to 50Ω in a single device wound
on a 4 inch core. A limited version on a 3 inch core is included.
Particularly intended to support "taming" the L/FCP when using Method B in
"Taming the Exasperating Inverted L".
- [Various] Many textual improvements and small additions in older articles
needing references to and from the Field Adjustable material.
- [Various] Readability Improvements and Clarifications.
The "Special Jumper" and accompanying text addresses a common problem with
tuning vertical or partly vertical antennas fed at the bottom of the
vertical member, which includes an L/FCP, that can invalidate an
RF-analyzer-generated antenna tuning. This was a solution to a major WTF
conundrum in the adjustable IsoT Field Trial. I had one of those
troublesome just-exactly-the-unfortunate-length coax runs.

Specifically included direct recommendation of and linkage to K9YC's 2018
cookbook. This came about when common mode chokes (CMC's) per K9YC's design
and chosen material outperformed some commercially available CMC's when
cleaning up CMC on coax in the field trial of the adjustable IsoT. Wanted
folks to know about that.

Added an article to construct a field adjustable turns ratio isolation
transformer (IsoT).  These have a step-up turns ratio to convert the low R
of an efficient L/FCP to 50 ohms while the installer trims the far end of
the horizontal wire for X = 0 at the chosen center frequency. This has been
a recurring request since the NCJ article  in 2012. Direct link is
k2av.com/FieldAdjIsoT.html .

In comparing instructions for fixed 1:1 ratio bifilar IsoT and the field
adjustable versions, a majority of the text is identical for both with the
field adjustable directions comprising nearly all the difference. The field
adjustable article contains the material not in common. Added links to and
from the main IsoT article.

The field trial at K2AV is described.

The field trial uncovered quite a bit which fed back into the particulars.
Some obvious inclusions to the loss list are in the works but not available
now.

Enjoy.

73, Guy K2AV
_
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Re: Topband: Poor Propagation or Noise?

[Guy Olinger K2AV]

Hi Roger,

If you go to

  https://www.blitzortung.org/en/live_lightning_maps.php?map=30

and have a look at the lightning situation here, it will give you an idea
what the omni antennas for RBN nodes are putting up against. Also what
stations without directional listening antennas are putting up with.

So far since summer 2021, in the eastern US, there has been no pause in
lightning QRN for winter. I remember when a teen that the QRN vanished in
the fall and did not reappear until spring. Winter was
noise-quiet, other than LORAN on 160. No more.

We are at the point of lightning, tornados, and high levels of QRN
year-round.

Blitzortung shows you what is going on lightning-wise around here. This
winter's speciality is lightning hundred or two hundred miles off the
coast, over the Gulf Stream, where one of these now frequent high velocity
cold fronts tries to bully out that rising Gulf Stream air. Once we are in
darkness, that stuff might as well be in our backyard. The noise follows
the sunset as it wanders west.

73, Guy K2AV

On Mon, Jan 10, 2022 at 6:26 PM Roger Kennedy 
wrote:

>
> I noticed that signals received from EU over last weekend by most of the US
> RBN sites were around 10 to 20dB lower than normal . . .
>
> Given that they show S/N (rather than absolute signal strengths), is that
> because 160m Propagation was poor . . . or because you had high noise
> levels
> (QRN) over there?
>
> Roger G3YRO
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: Region One stations below 1810 kHz

[Guy Olinger K2AV]

Just my .02 on this one.

The reader and especially the contest organizer not required to even
consider my opinion.

In a way it's like the ARRL's DX window in the ARRL160 used to be. It
was kept in there for years past its usefulness, especially since in all of
the later ARRL160's, the vast, vast majority of EU DX called CQ elsewhere
than 30-35, even when 30-35 was fairly clear.

It has been decades since there has been a radio location signal in
1.8-1.81. Loran has been gone for a LONG time.

What the political antics were at the World Radioalloction Conference
(WRC), I have no idea, but for some reason someone with some favors to pull
didn't want to let go of it. Maybe leftover cold war stuff, who knows. It
IS clear that quite a few, if not most, countries in Region 1 don't give a
hoot.

I would agree with an earlier post, that knowing what the COUNTRIES enforce
would be the only binding issue. And I don't see how to dump that on a
contest sponsor. You would be in effect trying to have the contest sponsor
impose enforcement of a WRC rule preserving a LORAN allocation for some
obscure political bartering situation.

For THIS PARTICULAR rule, I would say leave it to the operators and ignore
it. If there really was any region 1 stuff going on 1.8-1.81, that would be
quite the different story. The countries are the enforcing agencies, not
the conference. If a COUNTRY sees it for what it really is and refuses to
enforce, that is not my business.

Otherwise we have put the contest organizers in the position of being a
pawn for some country who won't let go of 1800-1810 unless they get some
certain something in exchange. Some NATO vs. Russia thing? Nobody seems to
know, enforcing the perception that this is some back closet, under the
table thing that no one but the 160m hams care about. If there is actually
more to that story, I'd love to hear it.

Let it go and leave published contest rules as they are. Someone tries to
pin down a contest sponsor, the answer is "no comment". Sponsoring a
contest is already an unreal amount of VOLUNTEER work.

73, Guy K2AV


On Sat, Dec 25, 2021 at 5:33 AM Henk Remijn PA5KT via Topband <
topband@contesting.com> wrote:

> In region 1 the frequency 1800-1810 is still allocated to Radiolocation,
> not to Amateur.
>
> However it is always possible that individual countries create different
> allocations.
>
> Similar to the upper frequency.
>
> 1810-1850 is primary Amateur.
>
> 1850-2000 is secondary Amateur.
>
> Some countries allow the complete allocation, some have restrictions.
> And some even have restrictions with individual exceptions.
>
> It is impossible for contests organizers to keep up with all those
> restrictions and exceptions.
>
> 73 Henk
>
> Op 25-12-2021 om 07:49 schreef uy0zg:
> > Hey
> >
> > Everything can be solved simply.
> >
> > To approve the rules for the whole World ( only for contest) - it is
> > impossible to work until 1810. It will be fair.
> >
> >
> > ---
> > Nick, UY0ZG
> > http://www.topband.in.ua
> >
> > Tree писал 2021-12-25 02:37:
> >> All -
> >>
> >> A friend of mine alerted me to the fact that he heard a QSO take place
> >> between someone in the USA and Europe below 1810 during the Stew.  I
> >> did a
> >> little research and verified that this QSO did take place - around 1805
> >> kHz.  However, the European reported the QSO on 1810 kHz.
> >>
> >> During this investigation, I have found more of these QSOs - including
> >> about two dozen with one station who was on 1808.9 kHz (per RBN).
> >>
> >> Perhaps the rules have changed recently, and these frequencies are
> >> permitted for Region 1 stations?  I see all sorts of countries in the
> >> list
> >> I have generated so far.
> >>
> >> And if these are "illegal" contacts - what should be done about them?
> >>
> >> And if a Region 1 stations modified his log to change the frequency
> >> information to make it look legit - is that unsportsmanlike behavior?
> >>
> >> Tree N6TR
> >> _
> >> Searchable Archives: http://www.contesting.com/_topband - Topband
> >> Reflector
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> > Reflector
> _
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> Reflector
>
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Re: Topband: W6WIN/7

[Guy Olinger K2AV]

 Confirm that,

It's N6WIN/7.

73, Guy

On Thu, Dec 23, 2021 at 12:58 PM HP via Topband 
wrote:

> Look at N6WIN on his QRZ page --
>
> Hank K7HP
>
> - On Dec 23, 2021, at 12:12 AM, Ed W0YK  wrote:
>
> | N6WIN/7?73,Ed W0YK
> |  Original message From: ok...@atlas.cz Date: 12/22/21
> 22:44
> | (GMT-08:00) To: topband@contesting.com Subject: Topband: W6WIN/7 Hi,
> does
> | anyone know the skimmer QTH of W6WIN / 7?He sometimes spots me, but I
> don't
> | know where he is? Many thanks. 73 Karel OKCF_Searchable
> | Archives: http://www.contesting.com/_topband - Topband Reflector
> | _
> | Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> _
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> Reflector
>
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Re: Topband: NA activity + Inv-L corner insulator

[Guy Olinger K2AV]

In the pulley snag conundrum, I found that the small marine grade stainless
steel, ball bearing pulleys would handle the black sheathed 3/16 in
parachute cord style rope and never a snag. They also pull very easy as the
bearing never freezes up from exposure to merely (vs. salt) water.

I also have a pair of insulators at the bend, one to the vertical wire,
another to the horizontal wire with a loop of "Flexweave" wire from the
horizontal to the vertical. That way in the wind there is no way for the
forces to be flexing a hard connection from the vertical to the horizontal.
After 2 or 3 (or was it 7 or 8) failures at this point with wires on the
ground it finally dawned on me that the wind constantly varied the angle
between the two wires, and fatigue at the joint was inevitable and
frequent.

YMMV but I'll never again have a "hard joint" at that point. I started this
in 2010, and have gone 11 years without the L coming down for that (one
dumb rope thing, though).

73, and long in the future may your heirs have to figure out how to get it
down out of the trees.

Guy K2AV

On Sat, Sep 25, 2021 at 4:23 PM  wrote:

> . Here in Ohio we are still having moderate QRN especially in the
> evenings. When I get on at our SR, the VK/ZL boys are often coming
> through fairly well with much less QRN.
>
> My INV-L has a ceramic insulator at the apex, which is held in place
> by 3/16" black synthetic rope of some kind ( Home Depot source) thrown
> over my 52 ft tall black walnut tree tied off to another tree. I dont
> use pullies since so often the rope slips off the roller and into the
> crack between the roller and the U-bracket. So I just tied a rope to
> the other side of the insulator and hoist.
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: Summer Stew Scores

[Guy Olinger K2AV]

Thanks, Tree.

Note that in the *summer* Stew this year, as of this post the high
scorer is K1LT who was running LOW power.

Ya just never know.

73, Guy K2AV

On Sun, Jul 11, 2021 at 1:27 PM Tree  wrote:

> Sorry for the delay in posting scores.
>
> The results for the Summer Stew are now available.
>
> www.kkn.net/stew
>
> Tree N6TR
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
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>
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Re: Topband: Hygain hytower on 160

[Guy Olinger K2AV]

I haven’t run a model on a hytower recently but helped one soul out of a
quandary with one a while back. Items that required attention:

1) Coax connection SO239 at base and its mounting device metal, etc, had to
be entirely replaced due to metallic corrosion.

2) Radials  were awful. Needed serious work to get past the “terrible”
rating up to “really poor but that will have to do”. Property had fairly
severe irregular elevation and boundaries.

3) When 1), 2) dealt with, 160 SWR got worse because feed R wasn’t anywhere
near 50 any more.

4) Cheep skinny coax had to be replaced.

5) Owner's opinion, results clearly better but still not good. It still was
a short vertical *without* a full size, dense, uniform length and spacing
radial field.

I don’t recall the coil being an issue, other than the SWR bandwidth was
narrowing down with repairs/improvements.

He did try an L off the hytower top later which improved things a bit more.
But at root it was still a short 160 vertical over a necessarily poor
radial field.

For the umpity-umpth time, for 160, the two ton elephant in the room is the
counterpole to whatever will be the aerial radiator.  We whack down a
DI-pole to a monopole which now needs a substitute pole for the missing
pole, a counterpole, usually referred to as radials or counterpoise. If
that counterpole is inferior, so will be your results.

First solve the radial/counterpoise elephant efficiently. Then do a tuning
something or other to handle the physical law that efficient shortened
antennas have reduced band width.

Someone posted about a vertical dipole. Absent discussion about size, cost,
difficulty of construction, support, feed method, survivability in weather,
yada, yada, it DOES solve the counterpole problem. At least for as long as
it stays up.

If all that was adequately solved by something durable off the shelf or
easily constructed, everyone would have a vertical dipole on 160. But we
all can count the number of 160 vertical dipoles around.

There ARE a few of those on the AM broadcast band. They are all
unbelievable MONSTER antennas that make your jaw drop if you ever get to
see one in person.  They DO work very well. And they occupy monster acreage
for the guy lines, etc.

See k2av.com for one answer to a necessarily poor radial field.

73, Guy K2AV


On Sat, May 8, 2021 at 6:12 AM Rob Atkinson  wrote:

> No personal experience but I've heard repeatedly over the years that
> the inverted L kit works way better than the loading coil.  This makes
> sense.   I think the inverted L kit consists of a trap you hang off
> the top of the BX section.  You probably supply the wire but on that
> I'm not sure.  I don't know if this kit is still being made or not but
> you might be able to fabricate a trap yourself.
>
> Rob
> K5UJ
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: 160m CW Activity

[Guy Olinger K2AV]

Was recently talking on 160 to one of my G3 acquaintances at his dawn.
He was apparently hearing me quite nicely. I gave him an honest,
accurate RST 289. Maybe closer to 189.

In between rapidly recurring S9/20 QRN crashes he was an honest S8 on
the K3, 3 or 4 S units above daytime noise levels. Never would have
kept it up, except for whose call sign it was.

That kind of QRN is the kind of thing one gets when it's -4C on one
side and 18C on the other of a front running from the Gulf of Mexico
up and down eastern US to Canada. That plus tornados, roof-ripping
straight line winds, etc. Won't get into the why business. But
whatever it is going on, it's real.

Getting on and working Top Band DX is something done for fun, not a
religious obligation, like making Sunday Mass. Time zone
differentials, people sleeping during their local nighttime. and
northern/southern hemisphere upside down seasonal differences are not
going to go away.

73, Guy K2AV

On Sat, Apr 3, 2021 at 7:25 PM List Mail  wrote:
>
> We typically have storm static from September till April, but winter 
> thunderstorms are possible as well. In addition, there is always Tropical 
> noise that may propagate in, when there are otherwise no thunderstorms 
> apparent across all of Australia.
> I’m still working a handful of European stations most mornings, but this 
> morning, the Polish DX Contest was on, so that made working any DX impossible.
> Most of our interesting DX is worked during our summer time, so we just have 
> to put up with the noise. Very little happens over winter, when it is nice 
> and quiet.
> 73, Luke VK3HJ
>
> Sent from Mail for Windows 10
>
> From: Roger Kennedy
> Sent: Sunday, 4 April 2021 4:16 AM
> To: topband@contesting.com
> Subject: Topband: 160m CW Activity
>
>
> I know a lot of you guys in North America are complaining that you are
> already getting a lot of QRN on the band, so aren't coming on . . .
>
> I guess we're pretty lucky here in Britain, as we only usually get
> thunderstorms in August . . . and even then, only for a handful of nights,
> so we don't get too many problems with static.
>
> But I just wanted to let you know that there are still quite a lot of us
> Europeans on 160m CW every night, looking for DX contacts . . . but most of
> us are calling CQ DX for ages, and lucky if we have more than 2 or 3 QSOs.
>
> However, propagation is still pretty good (I managed an S7 report from Texas
> last night), so if your noise level isn't too bad, hope a few more stations
> might make it on the band !
>
> 73 Roger G3YRO
>
> _
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Re: Topband: New Subject: 160M array feedline question

[Guy Olinger K2AV]

Hi, Roger

It sure seems like a lot of confusion arises when folks attempt concise
electrical and mathematical thoughts and calculations using words with very
broad and fuzzy definitions.  Words like radial, vertical, topload, etc.
can mean different things and can create remarkably confusing sentences and
descriptions.

Like “vertical with one elevated radial”. If one is thinking that radials
are a specific kind of wire group used as a counterpoise that effectively
minimizes radiation, then “with one radial” can’t be called a radial. It
simply is one end of a bent dipole, with one wire very close to and
parallel to the ground. Less lossy than some constructions, e.g. the
horizontal wire actually laying on the ground or buried, but decidedly
lossy. But there will be disagreement about a bent, ground-adjacent dipole,
quite more than one way of talking about that.

Being accused of not having a radial will undoubtedly be defended with "I
worked VK9ABCD at noon long path with a vertical over one radial."  But
that comeback does not pay any attention to whether one can include "one
radial" in a precise definition framework for discussion about how radials
work and why the commercial gold standard radials work so well. And of
course the worst of antennas can sometimes make QSOs in the best of
conditions, while the best of antennas can often barely make QSOs in the
worst of conditions. How can one possibly have an academic grade discussion
with all that flak flying around under the same list-serve thread title?

Since it’s not possible to referee a precise dictionary of such terms that
everyone will agree on, the answer to questions can’t be precisely
formulated with those terms IF what we’re looking for is precise answers or
at least answers good enough to risk precious hours, sore backs and
monetary expenditures.

In the end the answer to what wires and aluminum tubes do is what the
antenna modeling says they do, assuming that attempting the actual antenna
doesn’t expose a gotcha that requires additional work to produce in the
model what the wires and tubes actually individually do. The antenna model
is the only device we have that can break down the problem into small
pieces, calculate all the micro-interactions, and then add them up into
patterns and gain figures.

But even the high-priced pro antenna modelers get tricky to do right with
conductors very close to or in the ground, especially an issue on 160m.
Losses are the two ton elephant in the room on 160. Conversations with
fuzzy terms and concepts don't have a chance at accurately telling you
about RF losses, other than to warn they need to be dealt with.

We estimate efficiency by constructing the idea in a model, comparing
average and worst case ground results, and then doing a near field run set
to the ground surface. The former tells you how badly ground could affect
the performance and the latter shows if the design has created hotspot RF
field zones that can excessively induce ground losses, possibly pointing to
design improvements without the hotspots.

Verbal discussion is good for airing general ideas and concepts, providing
mental constructs for at least basically understanding involved
principles, if you can get consensus on definitions of terms. But as soon
as you want to know dB's, whether A is better than B, or not, you have to
do the work to put the idea up in models, avoiding all the gotchas, so all
the interactions between conductors, between conductors and ground, can be
calculated, added up and presented as loss figures and radiation patterns.

As to your mention of a typical VHF ground plane with counterpoise members
in a plane perpendicular to the radiating member, far field radiation from
those four will be minimized. When those four are "drooped", the four now
have a vertical component to their fields which modifies the pattern of the
main radiating member.

Frankly I think that the VHF "coaxial dipole" has long since replaced that
design. Consider the Celwave Stationmaster, etc, since even barely high
angle VHF radiation is lost altogether. One of their improvements in those
fiberglass encapsulated collinear antennas is to produce patterns that max
out three or even six degrees below perpendicular to the vertical to aim
max power "down" to the horizon or nearer service area from their high
mounting points. I don't see radials on those things. Still on some simple
low VHF antennas.

Using "down-angled" elevated radials in a 160 antenna has mild advantages
seen on a model. But one's physical construction has to have something
handling a loss avoidance need to keep RF off the tower beneath the
feedpoint. That seems to discourage that idea from becoming
popular, because without defeating RF on the tower beneath, that added loss
more than cancels the mild advantage seen in simple models without the
tower-to-ground treatment.

There actually is a way to accomplish tower loading, without tower base
radials using one or two FCP's, a 

Re: Topband: New Subject: 160M array feedline question

[Guy Olinger K2AV]

A counterpoise is what we do when the full size of a double-ended antenna,
dipole, OCF, etc is too large for us to build, maintain, etc. Very simply,
we want to jam the energy from the shield of our coax into the
counterpoise, and the energy from the center conductor into the radiating
element, the vertical, T, inverted L, etc, the aerial wire. Then we want to
get all that energy back from the counterpoise, none lost if possible, at
the phase reversal. Any you don't get back is mostly outright loss. With
commercial high grade radials you can show that the effective series
resistance of the counterpoise is 1/2, 1/3 or sometimes even 1/10 of an
ohm. That means that the aerial wire is radiating something like 50, 100
times the energy lost/radiated by the radials' connection to ground.

The two current destinations taken together MIMIC a circuit, because the
current into the counterpoise is the same, but opposite polarity as the
current into the radiating part of the antenna. If the currents are equal
and opposite, it looks like a circuit, walks like a circuit, quacks like a
circuit. You can model it with a fake circuit, and use Maxwell's equations
for circuits to predict what is gonna happen. There is no magic
circulation, just the ability to convince the coax it is hooked up to a
circuit. With the massive parallelism of a commercial grade radial field,
the radial's electrons are coupled into the ground as a reservoir, with the
push back from extra or missing electrons that will return the current when
the phase reverses. The more radials, the more even the radials, the longer
the radials, the lower the power lost to current through resistive
materials, lost to dielectric loss in dielectric materials, lost to
resistance in the wire. Not perfect return, but a nice, high percentage
return.

In free space, it is possible to construct a counterpoise that NEC4 can
accurately predict will radiate power to the far field at a rate 30 dB
below the RF current's energy. The essential loss is in the RF resistance
of the wire. You are talking about a counterpoise that is 98 or 99+ percent
efficient in free space.

We are not interested in a counterpoise radiating, or invoking loss in the
environment. Talking to the counterpoise, I'm telling it I'm giving it this
pile of energy. A half cycle from now I want it all back. No skimming off
the top. Maybe just a skoch.

A commercial quality radial field beneath a vertical is deliberately
intended to be non-radiating. Looking at the current around the base of the
vertical, the current to the east is exactly the opposite of the current to
the west, as are to the north and south, as are all opposite radial pairs,
therefore the fields generated are opposite, intended to be net zero in the
far field. That's on purpose, pretty much true, and exactly what the
engineers had in mind.

It is easy to show that there are unfortunate ham designs and
implementations of the counterpoise/aerial concept where not even 10
percent of the power is radiated skyward. That is the 160 meter two ton
elephant in the room that gets ignored an awful lot of the time.

73, Guy K2AV


On Mon, Mar 22, 2021 at 9:42 PM Adrian  wrote:

> Recycling signals at the feedpoint sounds more like a mismatch swr
> situation.
>
> The ground radials form half of the antenna, and that radiation from
> ground, in phase with the vertical radiation determines the field
> strength and take off angle.
>
> vk4tux
>
>
> On 23/3/21 11:31 am, Charles Moizeau wrote:
> > I feel it more appropriate to say that the function of ground-mounted
> radials is to harvest the radiation from a vertical antenna that splashes
> on the ground and return it to the feed point for recycling.
> >
> > 72/73,
> >
> > Charles, W2SH
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
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Re: Topband: Antenna thoughts

[Guy Olinger K2AV]

I would have to know just exactly how your "Ground R" was constructed to
comment. The two EZNEC variables for ground description are dielectric
constant and conductance. Also there is a lot depending on the T dimensions
and L dimensions in any comparison that would preclude any simple answer
that depended only on ground characteristics.

Also to really see what is going on, you would need superimposed patterns
modeled from a property's real dimensions. The radiation resistance
numbers sound like free space or Mininec ground, both with necessary
interpretation work to navigate.

The answers for an L depend enormously on the ratio of vertical to
horizontal, and also independently on the electrical length of the
horizontal as a top load. The simple comparison does not take account of a
good practice extending the horizontal to approximately 88 feet regardless
of vertical height, to make sure the vertical wire has the most integrated
current, all the way up to the bend, regardless of vertical wire height.
This venture into non-resonance for the sake of performance, reduces the
difference between a T and an L.

In a comparison of a T and an L, set the T using X vertical feet, with say
plus and minus 40 feet for the T wires. For a fair fight, the L must have
the same X vertical wire with an 80 foot horizontal, with the L's NVIS
angles and the enhancement on the side opposite the horizontal taken into
account.

An inverted L with 65 feet vertical and 88 feet horizontal, even over a
commercial grade counterpoise, certainly does not have 8 ohms
radiation resistance. And it is taking advantage of reduced current in a
counterpoise with ham grade radials.

Beyond that, first off the counterpoise should have been evaluated. On 160
antennas requiring a counterpoise, the counterpoise efficiency is the two
ton elephant in the room, with nothing in 2nd place on an awfulness scale.

Regardless of T and L particulars, even an accurate difference is heavily
swamped by any inefficiency in the counterpoise. "A few radials on the
ground" just to get one on the air, can be remarkably lossy.

A peek at the original poster's  photos on QRZ, show he was using a tower
to support the bend in his L. Add to any counterpoise loss the losses from
a tower supporting a close vertical wire (either T or L). A tower
supporting the bend of an L or the center of a T should be considered a
secondary winding in a tightly coupled transformer, with the vertical wire
as the primary, and the tower base connected to universal ground through a
big resistor

Those two issues can easily nullify the gain of an amplifier. The total
loss in the two issues smashingly exceeds the difference between T or L
aerial wire choice by an order of magnitude.

After one has taken care of the elephant in the room, back to the question
of T or L, the NVIS-defeating high angle hole in a T or pure vertical is a
real disadvantage for 160 only contests where same continent QSO's can
dominate the score. With the T you can have huge skips if the band goes
longish, losing a lot of Qso's. Worse, you can have your run frequency
taken because the other guy, in a very deep skip zone close to you,
couldn't hear you were there.

The comparison of a given specific T and L is actually a quite complex
question, and there are no simple answers. One has to assess the various
loss issues of the specific implementation and surroundings. No
one-size-fits-all answer. Sometimes one has to model every conductor on the
property, and often because of buried conductors, antenna and otherwise,
has to do it in EZNEC Pro/NEC4.

And often a huge improvement will have nothing to do with a T vs. L aerial
wire.

There are ways to minimize tower current when a tower has to be used to
support the aerial wires, but I've heard none of that discussed here.

73, Guy K2AV



On Tue, Mar 2, 2021 at 2:20 PM Dave Cuthbert  wrote:

> John, here are EZNEC results for your downward sloping inverted-L and your
> T-vertical.
>
> Inverted-L radiation resistance = 8 ohms
> T-vertical radiation resistance = 12 ohms
>
> How the radiation efficiency compares depends on your ground system. The
> efficiencies for 2.5, 5, and 10 ohm ground systems are compared:
> *AntennaGND RRad Eff  * *T over L*
> L   2.5   76%
> T   2.5   83%   0.4dB
>
> L   5.062%
> T   5.0   71%   0.6dB
>
> L   1044%
> T   1055%   0.9dB
>
> L2029%
> T20   38%   1.2dB
>
>Dave KH6AQ
>
>
>
> On Mon, Mar 1, 2021 at 10:20 PM John  wrote:
>
> > Hello all.I currently have a coaxial inv. L.apex at 50ft and rest going
> > out at abt 45 degrees.The end is abt 20-30 ft high.It has been a very
> good
> > antenna.I used a l because I did not have the option of 2 masts.I am
> > changing a bit.Doing away from vhf/uhf beams.So I 

Re: Topband: FCP Question

[Guy Olinger K2AV]

ZNEC help
files are probably the best single "book" you can get on the ugly and
necessary details of modeling. The helps are heavily indexed and best of
all they are searchable. :>) The challenge is that it's quite large,
excruciatingly detailed, and you have to know what something is called. But
if one is going to do it seriously, and especially if one is going to dole
out advice, RTFM is required, seriously. And if that nasty bit of hard work
is beyond resources or emotional tolerance (I do understand that, I was
close to giving it up at one time), maybe it's best to leave it alone and
let others.

I will also post to this reflector a piece that shows the increasing
warning over time of consequences for not following the help files'
"closely spaced wires" dictum. Being the semi-hoarder I am, I have
everything from V2 onward. I doubt many have that laying around. Very
interesting stuff.

73, Guy K2AV

On Fri, Jan 8, 2021 at 7:22 PM Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> On 1/8/2021 10:41 AM, Guy Olinger K2AV wrote:
> >
> > Hi Rick,
> >
> > There is no problem modeling an FCP. You do have to do the parallel
> > wires a certain way that’s documented in EZNEC since 1997 (version 2).
> >
> > What do you perceive to be the issue?
> >
> > 73, Guy K2AV
> >
> > On Fri, Jan 8, 2021 at 11:10 AM Richard (Rick) Karlquist
> I am vaguely aware that for a 2 wire line, EZNEC recommends that you
> replace it with the EZNEC transmission line element.  It also says
> that EZNEC will not model the effect of the line in common mode, AFAIK.
> In any event, the FCP consists of 3 parallel wires.  I have no idea
> what to do with such a structure.  So perhaps there is no problem
> modeling an FCP; it's just that I haven't got a clue.  I would
> be happy to learn how to do it.  Could you explain what to do or post an
> EZNEC file?
>
> 73
> Rick N6RK
>
_
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Re: Topband: FCP Question

[Guy Olinger K2AV]

Hi Rick,

There is no problem modeling an FCP. You do have to do the parallel wires a
certain way that’s documented in EZNEC since 1997 (version 2).

What do you perceive to be the issue?

73, Guy K2AV

On Fri, Jan 8, 2021 at 11:10 AM Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> It would be interesting to compare an FCP to
> N6BT's single spiral counterpoise.  It models
> well on EZNEC.  The FCP, unfortunately, cannot
> be modeled with NEC, AFAIK.
>
> Rick N6RK
>
> On 1/7/2021 9:35 PM, WI6X wrote:
> > Ted,
> > Read through Jim K9YC’s "Power Point slides for a presentation about
> 160M antennas at Pacificon in October 2012. Getting On 160M From a Small
> Lot (and Larger Ones Too).  October 2012”
> > http://k9yc.com/160MPacificon.pdf
> > K2AV Folded Counterpoise information begins on page 68 of the PDF.
> > 73,
> > Jim WI6X
> >
> >> On Jan 4, 2021, at 9:47 AM, Salvatore [Ted] K2QMF 
> wrote:
> >>
> >> Hello Topbanders,
> >>
> >> I have an inverted "L" with 4 elevated radials!
> >> I seem to have too much ground losses!
> >> I am wondering if I can add an 160 FCP to help with the ground losses??
> >> Any info would be much appreciated!
> >> Thanks and 73,
> >> Ted  K2QMF
> >> _
> >> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
-- 
Sent via Gmail Mobile on my iPhone
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Re: Topband: US1Q Stew

[Guy Olinger K2AV]

Hi Jamie,

That will be the contest sponsor's call, whose decision is final. Nor is
the sponsor required to explain decisions of this nature. Any explanation
would be the sponsor's choice. Nor do the published TBDC rules require that
an entrant must not have been DQ'd in any other contest for some length of
time.

I note that US1Q is not a winner, and not the top score from that region,
significantly beaten out by UW2M in nearly all the log stats in the score
listing. A USA remote RX, one would think would give a large advantage over
a station from the same region.

Tree might explain. He might not. That's entirely his choice.

73, Guy K2AV



On Wed, Dec 30, 2020 at 9:53 PM Jamie WW3S  wrote:

> I see his log was moved from checklog to High powerI thought there
> were questions as to the operation, wasnt this same station DQed in the
> CQ contest?.
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
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Re: Topband: Rogers dipole

[Guy Olinger K2AV]

I don’t at all doubt Roger’s reports. The grind comes when others
attempting Roger's successful methods report terrible results. There is
clearly something going on not at all well understood.

There are some number of reasons why it is nearly impossible to draw
universally reproducible conclusions from Roger's successes.

(1) The VOACAP program and its various published results are the root
genesis of a lot of individual hams’ propagation angle head-guess gut-feel
SWAG.

VOACAP cannot evaluate high angles and low angles in the same program run.
Fortran limitations. Common variables calculating space, etc.

That limited range wasn’t a problem for the original VOACAP developers
because they were servicing an inquiry on most reliable angles for
persistent commercial style broadcasting. As in a distant listener with
very limited radio and antenna hearing the station’s broadcast for an
ENTIRE and
PRESCHEDULED hour without dropouts.

The low angles were the recurring, reliable angles, even if not always
 the strongest path and certainly not the easiest to build to and
transmit.  The low angles got all the press because they serviced the money
that was paying for the development. High angles are not reliable for
broadcasting hour long programming. Even if the low angle was weaker, more
power/tower invested in the low angle transmission solves the need for
reliable propagation angles.

Getting through strongly for a minute or so on top of fading cycles to
allow hams to trade  names and RST on CW was *NOT* in VOACAP  developer
goals, though that certainly would satisfy and make joyful virtual legions
of ham operators who only need to hear their call and 599 coming back from
a new country.

7 MHz research at NY4A compared a yagi at 135' with a lower long 5 element
quad centered at 85', with unexpected results. Often the higher antenna
would experience deep fades on European stations while simultaneously the
lower quad maintained a steady S9 plus.

Trying to explain results with VOACAP, the higher angles on 7 MHz were only
obtained and collated when VOACAP was A) run for lows and then B) for
highs, and the results manually combined into a single presentation A)
*and* B). At that point you could see that for at least short periods the
high angle was predicted very useful. Certain angles were not invoked by
the high yagi, a deep null between major lower and upper lobes. But all the
literature only considered the low angle runs of VOACAP.

The high angle VOACAP results predicted frequent if short interval arrival
angles that were a vertical null in the model pattern for the yagi at its
height. After that we never bothered to put that yagi on EU DX. Always used
the quad. Regular VOACAP runs never exposed that in the same way they don’t
expose Roger’s riddle.

(2) There is no commonly available inexpensive equipment for hams to detect
what arrival angle is being heard. We INFER that it's coming high or low by
what antenna is receiving, and that distinction depends on our mental
remembrance of challengeable model plots (not measurements) of gain vs.
elevation.

(3) The veracity of (2) depends on whether the model's use of ground
conductivity and its effect on patterns is actually true in the wild
variation of ground conditions found across hamdom and local consistency of
same. From ham to ham across the globe there is WILD variation in ground
characteristics, almost never monolithic as necessarily presumed in the
model programming.

Since these days we have drones that can carry measuring devices that talk
back to a tablet over Bluetooth, some actual measurement of
almost-far-field vertical pattern is possible, but I have not seen such
measurements  carefully tabulated and compared to NEC predictions.

Everything I have seen is measured at the ground. Standing man with meter.
SMWM.

(4) We are sky wave folks. Measurement of TX at the ground tells us squat
about absolute sky wave intensity at the same azimuth. We can only infer
that azimuth-wise variation in field strength at the ground similarly
modulates azimuth field strengths at elevations significantly above the
horizon. Yet even that is suspect from NEC 3D pattern data on some antennas.

(5) At distances far enough to truly, absolutely be far field with any
local ground involvement completely accomplished, upper elevation
measurements would have to be at aircraft altitudes.

SMWM doesn't cut it. We need FLYING man with meter. FMWM needs helicopter
services, or high altitude drones. I have personally done helicopter
measurements at altitude, documenting azimuth AND vertical pattern from a
problem TX antenna for an FM broadcast station at 89 MHZ. I was NOT paying
the chopper service for that out of MY pocket change. Very pricey.

Got money, TX stuff like that can be done.

For both myself and the pilot, getting to GPS testing coordinates and
altitudes, constant coordination with RDU air traffic control, and constant
lookout for other traffic made that afternoon a 

Re: Topband: I need help proofing an Inverted L model I made please. 40’ x 143’, four 100’ radials, #14 wire.

[Guy Olinger K2AV]

Over really good dirt there isn’t too much difference.

The other problem is that the NEC ground approximation coding usually
underestimates loss. This is because the ground approximation in the model
uses a monolithic ground. Same stuff 100 feet down as at the surface. Real
dirt never is. Water tables, etc, yada yada. Or farm dirt plowed, dug for
the first two or three feet down, below that undisturbed and thoroughly
packed for hundreds of thousands of years. That's not monolithic. Nor are
many properties that were leveled for construction, or in ancient lands,
built on construction rubble accumulated for millennia. Simple velocity
factor measurement of a 152' dipole on ground is monstrously variable,
sometimes just varying orientation in the same back yard.

That doesn't account for lots of trees, roots where the only way to reduce
the increased counterpoise loss from dielectric losses is to reduce the
fields from the counterpoise. That's where the FCP comes from.

NEC uses monolithic ground in its ground approximation because more
complexity results in monstrous increases in run time. And we have to
remember that NEC is from a period where mainframe run times cost a lot of
money, and some computational methods could result in jobs not completing
in a month.

Reality skeptics sure of underestimated NEC ground loss include W7EL, EZNEC
author.

One way to get a better idea is to set ground characteristics in EZNEC to
gawd awful (in all compared designs) and rerun. As in (.005,1).  I do that
routinely on a design to stay away from designs that are more sensitive to
poor grounds.

E.g. set ground characteristics to (.005,1), then run a ground plane with 4
radials. Repeat with 8. Note the difference. Run at various radial heights.

Poor ground qualities happen and definitely appear to be the majority
rather than the exception. Designing for least sensitivity to poor ground
will protect the poor soul that has gawd awful ground in their backyard and
don't know it.

We spend thousands of dollars on transceivers and amplifiers and then go
cheep, cheep on radials? On 160, ground loss is the two ton elephant in the
room. Clean up after the elephant and send it to the zoo before you put
down new carpet.

73, Guy K2AV


On Fri, Dec 11, 2020 at 5:02 AM Artek Manuals 
wrote:

> Jim et all
>
> I agree with what you say on all points when it comes to radials on the
> ground and salt water affects.
>
> However I have always wondered about elevated radials . The NEC ( both 2
> and 4) models (not that those are to always be trusted) show very little
> (if any) improvement beyond four elevated radials, you have any theories
> on why that is? Intuitively (also not to be trusted) that is a lot of
> real estate in the spaces between
>
> Dave
> NR1DX
>
> On 12/11/2020 4:37 AM, Jim Brown wrote:
> > On 12/10/2020 11:14 PM, Raymond Benny wrote:
> >> With said, I believe my ground absorption is very high so I feel the
> >> higher
> >> numbers of radials helps greatly with my vertical efficiency and
> >> radiation.
> >
> > Hi Ray,
> >
> > The soil affects us in two important ways. First, poor soil burns
> > transmitter power underneath the antenna and it's near field. We use
> > radials to shield the soil from the field, and to supply a low
> > impedance path for return current. Magnetic fields produced around
> > each radial by virtue of current flow couples loss in the earth into
> > the radials in the form of series resistance. Loss in each radial is 1
> > squared R; each time we double the number of radials the current in
> > each is divided by two, so the power coupled to the earth by each
> > divides by four. So the more radials, the less power is coupled to the
> > earth. THAT'S why more is better. The result of all this is that loss
> > in the soil under the antenna reduces the total strength of our signal
> > by that amount.
> >
> > The second effect of soil is in the far field, where we field radiate
> > hits the earth and is reflected by it to form the vertical pattern.
> > The better the conductivity THERE, the our pattern will be both
> > stronger and at a lower angle. An antenna with its base just above sea
> > water is the extreme example of this -- the reflection is extremely
> > strong, and it is at a VERY low angle.
> >
> > We can help the first of these two effects with a good radial system,
> > but the only thing we can do about the second (the far field
> > reflection), is to move where there is better soil. Most of us live
> > where we do because we like living there for reasons other than radio.
> > And that includes me and my XYL.
> >
> > 73, Jim K9YC
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> > Reflector
>
> --
> Dave manu...@artekmanuals.com www.ArtekManuals.com
>
> --
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
> _
> Searchable Archives: http://www.contesting.com/_topband - 

Re: Topband: FW: CQWW a bust this year

[Guy Olinger K2AV]

Hi Nick,

I have a limited setup, only an inverted L over an FCP on 160 (not like
W3LPL's 160m 4 square cannon). With basically no time to operate, I managed
about 60 minutes in three spells on 160m, 45 QSO's, 17 zones, 30 countries,
all S

I worked EU and AF in zones: 14: 4, 15: 7, 16: 1,  20:1, 33: 1, 35: 1.  Not
sure the 45/17/30 in one hour on 160 from a modest station allows room to
blame things on the band.

Good antenna for RX, and an EFFICIENT transmit antenna are always key to
making it. These will be even MORE important for 160 success as we make our
way into cycle 25.

160 seemed slow this time, but I didn't hear nearly as many stations on the
band, weak *or* loud, as in the past. Think they were having too much fun
on the higher bands in conditions which are most likely the opening round
of solar cycle 25 propagation. Get ready to do DXCC on 6 meters this time
around.

73, Guy K2AV

On Tue, Dec 1, 2020 at 1:32 PM uy0zg  wrote:

> Hi
>
> Frank
>
>
>
> May I ask how many QSOs with zone 16 did you have on 160 meters in this
> CQ WW ?
>
>
> ---
> Nick, UY0ZG
> http://www.topband.in.ua
>
> donov...@erols.com писал 2020-12-01 20:20:
> > Of course Lee is absolutely correct.
> >
> >
> > Many 160 DXers who have had difficulty with receiving antennas
> > have given up too easily during the troubleshooting process.
> >
> >
> > 73
> > Frank
> > W3LPL
>   Topband Reflector
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: Cycle 25 predictions

[Guy Olinger K2AV]

As a lifetime true-blue dyed-in-the-wool statistical wonk, this solar cycle
presentation is the statistical equivalent of Jascha Heifitz playing the
violin.

We always have to wait and see how things play out, for sure. But... And a
very delightful "but..." at that...

But... For the first time in my lifetime this presentation on the Hale
Cycle describes a method capable of "predicting the solar cycle past",
being able to predict what happened at a point in the past only from what
was known prior to that point in the past.

The Hale Cycle is a 22-ish year cycle with a positive and negative half.
The Hale halves vary from 8 to 14 years, if I heard that right. Our 11-ish
year sunspot cycle apparently derives from the two phases of a Hale Cycle.

No explanation for what drives the variation in the Hale Cycle, but that's
for all the budding solar physicists.

There is a passing reference to a correlation between Hale events and El
Nino, climate stuff. But not expounded.

The flip in the Hale Cycle is a sharp, measurable event, maybe happened
last month, would explain going from nothing on 10m and 15m in October, to
bum 160 and lively high bands again in the CQWW CW.

Won't spoil it for the viewer, but there is a surprising estimate for cycle
25, using the same method that correctly predicts cycle 19 from cycle 18,
the Dalton minimum from prior cycles, basically predicts 20th century solar
cycle intensities.

This one is a must-watch:  https://youtu.be/lRNJPkQPo_g

The statistical methodology is absolutely top-shelf. Wow. It's really great
to see something done this well.

73, Guy K2AV

On Tue, Dec 1, 2020 at 8:33 AM Michael Walker  wrote:

> It isn't about the 11 year Solar Cycle.  That is just the symptom.
>
> It is about the 22 year Hale Cycle.
>
> Well worth the watch.  I won't spoil the ending.
>
> Mike va3mw
>
> https://youtu.be/lRNJPkQPo_g
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: Wednesday CW DX Activity Night

[Guy Olinger K2AV]

I heard the 7Q7 call sign here in NC exactly once, of course at the tippy
top of a long QSB cycle, which then immediately dove into the noise not to
be heard again in the 30 minutes
before I had to go downstairs.

8’s and 9’s appeared to be hearing him. Go figure.

73, Guy K2AV

On Thu, Nov 19, 2020 at 10:44 AM Thomas Hoyer via Topband <
topband@contesting.com> wrote:

> Observation from my little gun station in eastern PA is that propagation
> seems to have moved more to the west of me, western PA, Ohio and further.
> Whereas for the last two weeks or so I was hearing EU fairly well given my
> S5 noise level which is quite for me.
> Worked the KP2 and YL stations last night but as Roger alludes to some
> deep QSB made it a couple try QSO.
> That 7Q7 was drawing a lot of activity bit I could not hear him at all.
> Seemed like stations to the west of me were hearing better.
> TomW3TA
>
>
> -Original Message-
> From: Roger Kennedy 
> To: topband@contesting.com
> Sent: Thu, Nov 19, 2020 9:40 am
> Subject: Topband: Wednesday CW DX Activity Night
>
>
> Once again, lots of stations on the band last night from both sides of the
> pond . . . good have such a nice turnout.
>
> However, quite deep QSB on most signals, and propagation didn't seem as
> good
> as the night before (when I worked several stations right across to the
> West
> Coast).
>
> Thanks once again to all that made the effort to come on 160 to have a few
> QSOs . . . let's hope we can keep the DX CW activity going again next
> Wednesday.
>
> 73 Roger G3YRO
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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_
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Re: Topband: ARRL 160M and 1830-1835 change

[Guy Olinger K2AV]

I’m glad that rule is gone from the ARRL 160. THEORETICALLY that should
have worked. What I observed year over year was that the ** DX ** didn’t
use it that much. Not altogether sure why.

I suspect that S stations didn’t start their scanning in the DX window
because most of their contacts were going to be NA not EU. So park up in
the DX window for your CQ and you’re not heard as much as down in 10 to 30.

For whatever reasons the window never seemed that busy. Now with 1840-44
taken over by FT8, being able to use all of 1810-40 seems a good move.

Personally I’ve had a line noise here for 20 years I’ve never found the
source. It has a never-moves null at 1831 that I will be able to use in the
ARRL 160 now.

73, Guy K2AV

On Fri, Oct 23, 2020 at 6:26 AM Roger Kennedy 
wrote:

>
> I actually think that a Window during Contests to work DX stations is a
> good
> idea . . .
>
> It can be quite difficult to work NA stations in a Contest if they are
> being
> repeatedly called by other strong NA stations !
>
> One of the other issues is that many of us come on the various Top Band
> contests not to enter, but just to work DX stations.  SO I am reluctant to
> call CQ, as I will get called by hundreds of Europeans (which I haven't got
> up in the middle of the night to work!)
>
> I often hear lots of DX stations, but I can't call them as they are just
> calling other people on their frequency . . . it's quite frustrating.
> (perhaps they don't want to put out a CQ for the same reason that I don't?)
>
> To try and get round this, I sometimes put out a CQ DX call in a Contest .
> .
> . do you think that's acceptable?
>
> Of course on SSB it's much easier . . . you can actually say that you're
> listening for NA or DX . . . hopefully some of the NA stations on 160 in
> the
> Contest this weekend will occasionally listen for Europe !
>
> 73 Roger G3YRO
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: Good Conditions, Little Activity

[Guy Olinger K2AV]

Is this thread’s subject material really just whining?

Well, FT8 does some really good things that typical CW operation doesn’t
usually want to bother with.

1) use of a calling frequency (“SSB” “carrier” frequency)
2) constant monitoring
3) highly efficient use of VERY close frequencies.  Never needs retuning.
4) computer driven to allow attention to band over broad time spans.
5) technical attention to issues effectively resulting in improved
sensitivity
6) dB above noise replaces ancient RST signal reports.

One aspect of currently practiced CW is doing something we have enjoyed all
our lives. I’m not knocking that, particularly CW contests. But FT8 exposed
everything difficult about casual low band dxing. With some really good
conditions to North Carolina, I have had just a handful of great
transatlantic old style extended 160 CW QSO’s to G DL SP OK

But I know those lovely episodes can’t be regular, I don’t morose not being
able to do those every Wednesday. Instead I get in the CWT one hour mini
test whose 0300 session usually finishes out with some of the mob gone down
on 160 and enjoy an occasional EU contact in the last ten minutes.

In those sessions, even through summer months, have had QSOs with USA west
coast AND European RBN.

But casual DXing on weeknights, with time differences that require shifting
waking hours around? Some folks have the circumstances for that. God bless
em.

Stew Perry, ARRL and CQ 160’s are on weekends and scheduled years in
advance. Those are reserved in advance and the discombobulated waking hours
don’t affect routine life. I can get away with that and don’t mind
struggling through the Monday following.

Every now and then I’d like to go back to 1959, my NC2-40D & 807
transmitter working the NTS 80m traffic nets. But that’s all gone. NTS
refused to modernize and adapt to modern life and circumstances. What
continued was the familiar enjoyable pattern from the 50’s. I totally
understand that. But I don’t pretend that is extensible to our current
circumstances.

How WOULD you do CW pulling stuff from FT8 advantages, and with patterns
that could actually be done manually as well as autonomous computer?

73, Guy K2AV


On Fri, Oct 9, 2020 at 9:27 AM GEORGE WALLNER  wrote:

> Hans,
> FT8 did not kill Ham radio; it has changed it. Computer are doing that to
> many aspects of our lives, some them we like, and some we don't.
> There are things that you can't do with FT8: you can't win a CW or SSB
> contest (even RTTY), nor can you get a CW DXCC, etc.
> You can still show your skills.
>
> 73 and CU on CW,
> George,
> AA7JV/C6AGU
>
>
>
> On Fri, 9 Oct 2020 10:27:11 +0200
>   Hans Hjelmström  wrote:
> > SORRY Roger
> >FT 8 has killed Ham radio ,when you need your own skill and not trust
> > a computer to make your connection.  I will NEVER use that
> mode.Unfortunately MNI MNI Sweden Hams have  almost gone QRT for
> good,because of this FT-8 and lack of activity on hearing modes.
> >
> > Kind regards
> >
> > Hans SM6CVX
> >
> >> 9 okt 2020 kl. 10:20 skrev Roger Kennedy  >:
> >>
> >>
> >> It's such a shame that 160m Conditions for DX have been pretty good
> over the
> >> past week or two . . .
> >>
> >> Yet there are so few CW stations coming on the band !
> >>
> >> I hear lots of us Europeans putting out endless CQ DX calls . . . but
> often
> >> getting no replies, despite good RBN Reports confirming the band is
> open.
> >>
> >> Roger G3YRO
> >>
> >>
> >> _
> >> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
-- 
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_
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Re: Topband: BOG Front to back

[Guy Olinger K2AV]

Just to point out that there is NO one-size-fits-all PHYSICAL length for
BOG best f/b.

There is an ELECTRICAL length that far better defines it. And the
electrical length of a fixed length of wire varies wildly all over the
place, depending on the ground underneath, and the spacing to actual dirt
ground. VF measured on 151 foot (46 m) dipoles-on-ground varied from 45% to
85%, some changing wildly just rotating the wire 90 degrees around its
center in the same back yard.

So you make a dipole on the ground, in the place you intend to put the BOG,
and at the same height and using the same installation method you intend
for the BOG. You trim it to make it resonant at 1140 kHz. Then you solder
and insulate the center and add the BOG stuff to the ends.

What you have done with that method is to create a series of 160m BOGs that
all have a certain design ELECTRICAL length.

73, Guy K2AV

On Sat, Sep 12, 2020 at 9:41 AM Artek Manuals 
wrote:

> Mike
>
>
>
> I have taken the liberty of changing to subject line to more accurately
>
> reflect the content of your reply on the Waller Flag thread
>
>
>
> After much reading and a lot of personal experience and experimentation
>
> I am of the opinion that BOG front-to-back is a function not only the
>
> length but the soil type as well.
>
>
>
> I experimented with 350',  300', 250', and 200'  long bogs all in the
>
> same direction, In my case the shorter 200' long BOG, over very dry ,
>
> well drained, sandy soil clearly had better F/B than the 250' , 300',
>
> 350'   ( F/B on the 350' was the worst of all of them..anyone want some
>
> 50' pieces of RG6?) . When I run out of other things to do I plan on
>
> trying a 175' and 150' but not in the next year.
>
>
>
> A friend of mine living in another part of the country compared his 200'
>
> BOG on laid  top of rich Midwest farm loam to mine and  was very
>
> surprised that my front to back was so much better than his. What the
>
> optimal length is for his particular soil is still TBD. Another friend
>
> with sandy soil but in a very near salt water environment ( he lives
>
> along a  canal with ocean access, i.e salt water)  also reported poor
>
> front to back , for sure we surmise his soil is much more conductive
>
> than mine) .
>
>
>
> The moral I guess is I would start shortening your BOG and see if the
>
> front to back improves
>
>
>
> Dave
>
>
>
> PS: I too use RG6 for all my BOGS and the feedlines and a dozen or more
>
> turns on a #31 torroid at each end of a 125' feed lines significantly
>
> reduces broadcast band induced signals
>
>
>
>
>
> On 9/12/2020 8:26 AM, Mikek wrote:
>
> >>
>
> >
>
> >  My Technical knowledge is limited but, I have built directional AMBCB
>
> > antennas. Feed line isolation is critical to make a directional
>
> > antenna, directional! I have been criticized and been told, coax cable
>
> > does not pick up signal. Must be I don't use the right coax.
>
> >
>
> > This from a previous post I made after I ran out and tested a 230ft
>
> > Coax and a 230ft 18ga twisted speaker wire, to see what BCB stations
>
> > they received.
>
> >
>
> >   "I found I received 13 stations with up to 5.5 S units on the
>
> > properly terminated coax. I tried many things to reduce signal pickup,
>
> > chokes, transformers, grounds, several chokes and transformers, but
>
> > could never get it to be quiet. So after reading some info about
>
> > phased antennas using speaker wire, I ran a twisted speaker wire out
>
> > to where my antenna was to start.
>
> > After terminating that, I found I only received 4 stations, 3 were
>
> > audible but at zero on my S meter and one that was almost 1 S unit.
>
> > Do I think the speaker wire has more loss than the coax probably, but,
>
> > I seem to have plenty of signal and it doesn't have much
>
> > signal ingress compared to the coax."
>
> >
>
> >   I have since went to Cat5 cable for my receive antenna. I started in
>
> > my haste just connecting Cat5 to my radio, terrible idea, but I
>
> > learned from it.
>
> >
>
> >  I tried several things to quiet the Cat5 and came up with something
>
> > that works very well for quieting the Cat5 in_MY_ situation.
>
> >
>
> > I have the 235ft of Cat5 connected to a 260ft (property limited) BOG
>
> > that I use mostly for the AMBCB. The BOG points N/S, it seems to have
>
> >
>
> > attenuated side lobes but not much front to back.
>
> >
>
> >  After reading a Laird Cat5 common mode article, I used their info to
>
> > help me build my signal ingress reduction box. If you're interested in
>
> > seeing what
>
> >
>
> > worked for me, click here.
>
> >
>
> >>
> https://www.dropbox.com/s/e1lq7fxv0kggi5d/bog%20final%20design%20may%2030%202020%20common%20mode%20attenuator.jpg?dl=0
>
> >>
>
> > KF4ITA Mike Knowlton
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
>
>
> --
>
> Dave manu...@artekmanuals.com www.ArtekManuals.com
>
>
>
> --
>
> This email has been checked for viruses by Avast antivirus software.
>
> 

Re: Topband: Shunt Fed Tower SWR Troubles

[Guy Olinger K2AV]

I agree about the padding caps, good addition. I know of instances of both,
fixed caps with insufficient current rating, and the balun insufficient for
160m blocking.

If the caps were starting cold, there would be some period where the SWR
was normal and then start climbing.

The 160m stressed balun would change SWR somewhat, but immediately with
increased power, indicating saturation. Then after a period of operating,
when the core reached the Curie temperature, it would fall off the table.

Once in a contest at a multi/two station, padding caps got hot and failed
in parallel with a vacuum cap being used to detune a tower. I walked
outside and was confronted by a strong acrid smell. Of such I informed the
owner who could actually see the padders being destroyed in the
dark, knowing where they were. I saw those caps a few days later, and it
was like the "Really Most Sincerely Dead" song in the Wizard of Oz.

73, Guy K2AV

On Thu, Aug 27, 2020 at 3:28 PM Jeff Blaine  wrote:

> Had the same issue as you Lloyd here - in a prior antenna matching net.
> On 160 it would start to drift after calling CQ a few times.  I did not
> flip to vac caps.  But instead ended up using lower valued, paralleled
> doorknobs, so that the current was shared among multiple paralleled caps
> and as a result the drift was much less from what I assume was a larger
> surface area to dissipate whatever heat there was.  Could have been a
> lousy initial cap as well.  Hard to say.
>
> But if the op has fixed pads in there, this is definitely a place to look.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
>
> On 8/27/20 2:23 PM, Lloyd - N9LB wrote:
> > Hello Dale,
> >
> > I had this same problem.
> > In my case I discovered that it was the "Doorknob" capacitors heating up
> and
> > changing value.
> > I had installed some fixed value doorknobs to "pad" the variable cap in
> the
> > matching circuit.
> > Changed to Vacuum Caps, no more problems.
> >
> > 73
> >
> > Lloyd - N9LB
> >
> >
> > -Original Message-
> > From: Topband [mailto:topband-bounces+lloydberg=tds@contesting.com]
> On
> > Behalf Of Dale Drake
> > Sent: Thursday, August 27, 2020 12:06 PM
> > To: topband@contesting.com
> > Subject: Topband: Shunt Fed Tower SWR Troubles
> >
> > Here's my problem. I'm experiencing SWR problems
> > with 160M shunt feed on my tower.  Using a gamma
> > match with HV air variable caps I am able adjust
> > the tap point to get a very nice SWR curve using
> > my AA-35 Zoom analyzer.  The problem I having is
> > that when transmitting the SWR goes up with power
> > and if I key-down for very long the SWR rises
> > rapidly and takes off.
> >
> > My set up is 70ft Rohn 25 with about 22 feet of
> > mast above the top of the tower.  At the top of
> > the mast is a Diamond 2M/440 vertical.  At 15 feet
> > above the tower top is an XM-240 and 2 feet above
> > the tower top is a 4el SteppIR.  The elements of
> > the SteppIR are fully retracted.  All of the coax
> > and control lines are run from ground level inside
> > the tower up to the service loop. On the mast
> > above the tower the coax is tywrapped to the mast.
> > There are 60 ground radials with an average length
> > of 90ft.  The reflector of the XM-240 is insulated
> > from the boom and the driven element is fed
> > through a Comtek 1:1 balun. All of the coax
> > shields are grounded at the tower base.
> >
> > I have an 80M gamma matched shunt on this tower
> > that plays FB with no weird SWR stuff going on.
> >
> > I suspect that what is causing my 160M trouble is
> > that RF is coupling through the 40M coax, through
> > the balun and into the driven element. Somehow the
> > coupling changes with power, which I don't
> > understand.  I suspect that when I key-down and
> > the SWR takes off, the core in the balun is
> > getting hot and the magnetic properties are
> > shifting until it cools off and returns to normal.
> >
> > My plan to try to correct this problem is to
> > connect the center of the XM-240 reflector to the
> > boom and to mount a box at the XM-240 feed point
> > with 2 vacuum relays that I will use to connect
> > the driven element to the boom when I'm on160.
> > This will be a considerable effort and expense so
> > I'm looking for the group's input as to the
> > soundness of my plan or if there may be other
> > approaches that would be less difficult to try
> > first.
> >
> > Thanks,
> >
> > Dale, AA1QD
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt Fed Tower SWR Troubles

[Guy Olinger K2AV]

While air variables certainly do flash over, the effect is sudden, and has
no "ramping up" effect.

From Dale's original post:  "The problem I having is that when transmitting
the SWR goes up with power
and if I key-down for very long the SWR rises rapidly and takes off."

He can observe the SWR rising. He can see the needle getting higher and
higher. Flashovers bang the needle high. The lack of "bang the needle" or
it's digital display equivalent rules out flashover, carbon arc paths.
Also, carbon arc paths, once established, tend to make the high SWR
permanent, there all the time until the problem is repaired.

The "SWR goes up with power" may indicate increasing core saturation with
power which is another finger pointed at the insufficiency of the balun in
use for a loaded tower.

73, Guy K2AV

On Thu, Aug 27, 2020 at 2:20 PM Steve Lawrence via Topband <
topband@contesting.com> wrote:

> I experienced wide spaced air variables flash over at moderate to high
> power in my shunt feed omega match. I changed to vac variables. That solved
> the problem with the additional benefit of easier tuning via the vac cap's
> verniers.
>
> GL - Steve WB6RSE
>
> > On Aug 27, 2020, at 10:58 AM, John Harden, D.M.D. 
> wrote:
> >
> > I am wondering if the air variable is flashing over. I am willing to bet
> that a vacuum variable would correct the problem. I use two (2) Vacuum
> variables in an Omega match.
> >
> > 73,
> >
> > John, W4NU
> >
> >
> >
> >
> >
> >
> > Sent from my iPhone
> >
> >> On Aug 27, 2020, at 1:38 PM, Guy Olinger K2AV 
> wrote:
> >>
> >> Hi Dale,
> >>
> >> The RF voltage is always looking at the far end (stuff on the end away
> from
> >> the tower base) to jump onto.
> >>
> >> *** Provide a deliberate, designed, long-term weather survivable
> metallic
> >> path to the boom of the highest yagi and provide a low R path from the
> >> boom to BOTH sides of at least one element at either END of the boom.
> This
> >> will drastically reduce current via unintended paths.
> >>
> >> You will have to retune the match.
> >>
> >> This is much easier for a parasitic element, where the center of an
> >> insulated element can be just strapped to the boom. But you should also
> >> replace the balun. It will remain a source of RF loss, even if it
> doesn't
> >> change value or burn up.
> >>
> >> RF current heating of a "balun" comes about because an engineer is only
> >> designing the balun for the performance at 40 or 20 meters. The R of
> such
> >> a device on 1.8 MHz can be quite low. I have measured one that worked
> FB on
> >> a tribander that was only 173 ohms on 160. That will get very hot at
> power
> >> and its effect on the tuning at the tower base can be enormous. And it
> is a
> >> guaranteed source of RF loss that throws away dB's of your amp's power.
> RF
> >> heating of a ferrite device gets to a point where the R
> characteristics
> >> suddenly fall off the table. 80 meters likely just doesn't quite get to
> >> that temperature because the R of the balun is higher on 80m
> >>
> >> You still may need to change that device for something with good stiff
> R
> >> at 160, so it will not heat up and change. The 160 RF will still try to
> go
> >> there. It just needs to be solidly blocked. See the Balun Designs
> 1116dx (x
> >> is one of 6 or 7 hardware configurations, same innards). Or go to K9YC's
> >> web site to make your own. Jim has some recent designs, excellent R
> for
> >> 160 based on a new monster #31 ferrite core & RG400.
> >>
> >> Good luck, 73, and stay safe from that virus,
> >>
> >> Guy K2AV
> >>
> >>> On Thu, Aug 27, 2020 at 1:06 PM Dale Drake 
> wrote:
> >>>
> >>> Here's my problem. I'm experiencing SWR problems
> >>> with 160M shunt feed on my tower.  Using a gamma
> >>> match with HV air variable caps I am able adjust
> >>> the tap point to get a very nice SWR curve using
> >>> my AA-35 Zoom analyzer.  The problem I having is
> >>> that when transmitting the SWR goes up with power
> >>> and if I key-down for very long the SWR rises
> >>> rapidly and takes off.
> >>>
> >>> My set up is 70ft Rohn 25 with about 22 feet of
> >>> mast above the top of the tower.  At the top of
> >>> the mast is a Diamond 2M/440 vertical.  At 15 feet
> >

Re: Topband: Shunt Fed Tower SWR Troubles

[Guy Olinger K2AV]

Hi Dale,

The RF voltage is always looking at the far end (stuff on the end away from
the tower base) to jump onto.

*** Provide a deliberate, designed, long-term weather survivable metallic
path to the boom of the highest yagi and provide a low R path from the
boom to BOTH sides of at least one element at either END of the boom. This
will drastically reduce current via unintended paths.

You will have to retune the match.

This is much easier for a parasitic element, where the center of an
insulated element can be just strapped to the boom. But you should also
replace the balun. It will remain a source of RF loss, even if it doesn't
change value or burn up.

RF current heating of a "balun" comes about because an engineer is only
designing the balun for the performance at 40 or 20 meters. The R of such
a device on 1.8 MHz can be quite low. I have measured one that worked FB on
a tribander that was only 173 ohms on 160. That will get very hot at power
and its effect on the tuning at the tower base can be enormous. And it is a
guaranteed source of RF loss that throws away dB's of your amp's power. RF
heating of a ferrite device gets to a point where the R characteristics
suddenly fall off the table. 80 meters likely just doesn't quite get to
that temperature because the R of the balun is higher on 80m

You still may need to change that device for something with good stiff R
at 160, so it will not heat up and change. The 160 RF will still try to go
there. It just needs to be solidly blocked. See the Balun Designs 1116dx (x
is one of 6 or 7 hardware configurations, same innards). Or go to K9YC's
web site to make your own. Jim has some recent designs, excellent R for
160 based on a new monster #31 ferrite core & RG400.

Good luck, 73, and stay safe from that virus,

Guy K2AV

On Thu, Aug 27, 2020 at 1:06 PM Dale Drake  wrote:

> Here's my problem. I'm experiencing SWR problems
> with 160M shunt feed on my tower.  Using a gamma
> match with HV air variable caps I am able adjust
> the tap point to get a very nice SWR curve using
> my AA-35 Zoom analyzer.  The problem I having is
> that when transmitting the SWR goes up with power
> and if I key-down for very long the SWR rises
> rapidly and takes off.
>
> My set up is 70ft Rohn 25 with about 22 feet of
> mast above the top of the tower.  At the top of
> the mast is a Diamond 2M/440 vertical.  At 15 feet
> above the tower top is an XM-240 and 2 feet above
> the tower top is a 4el SteppIR.  The elements of
> the SteppIR are fully retracted.  All of the coax
> and control lines are run from ground level inside
> the tower up to the service loop. On the mast
> above the tower the coax is tywrapped to the mast.
> There are 60 ground radials with an average length
> of 90ft.  The reflector of the XM-240 is insulated
> from the boom and the driven element is fed
> through a Comtek 1:1 balun. All of the coax
> shields are grounded at the tower base.
>
> I have an 80M gamma matched shunt on this tower
> that plays FB with no weird SWR stuff going on.
>
> I suspect that what is causing my 160M trouble is
> that RF is coupling through the 40M coax, through
> the balun and into the driven element. Somehow the
> coupling changes with power, which I don't
> understand.  I suspect that when I key-down and
> the SWR takes off, the core in the balun is
> getting hot and the magnetic properties are
> shifting until it cools off and returns to normal.
>
> My plan to try to correct this problem is to
> connect the center of the XM-240 reflector to the
> boom and to mount a box at the XM-240 feed point
> with 2 vacuum relays that I will use to connect
> the driven element to the boom when I'm on160.
> This will be a considerable effort and expense so
> I'm looking for the group's input as to the
> soundness of my plan or if there may be other
> approaches that would be less difficult to try
> first.
>
> Thanks,
>
> Dale, AA1QD
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Tuning a 2el parasitic array

[Guy Olinger K2AV]

With the era of cheap VNA's it does seem time to move forward. Especially
with wire yagi's, you can get VNA's with smartphone style 5V USB charged
batteries that talk to a tablet running supplied software, communicating
with bluetooth. You can put the VNA right at the feed, and pull it up in
the air so ground effects are representative and can be watched with
changing elevation. None of the complications of the significant cable
between VNA and the feedpoint.

Zowie, is that way less work than the good ole days. Now I use my lab
calibrated FIM41 field strength meter to do before and after documentation.
And from time to make sure it's still performing by staying at the
benchmark. Not for making adjustments. As Steve mentioned, too much motion
for these old bones.

73, Guy K2AV

On Sun, Jun 21, 2020 at 3:14 PM VE6WZ_Steve  wrote:

> Hi Rick,
> Yes you can field test for max F/B, but that is far from ”simple” and easy
> to do.  I have done it. Many times over the last 22 years.
>
> With a Yagi on the tower I used both an external source as well as an
> external RX in the field and tried to tune for max F/B.
> Using an external source I also plotted real-time polar plots of the Yagi
> pattern.
> However...In practice, here is how it goes:
> To check F/B….we rotate Yagi forward…record measurement, back to shack,
> rotate Yagi to back, record measurement.  Then guess if we need the
> parasitic longer or shorter… Climb the tower adjust element (or adjust
> lumped load at the element). test again. Guess again….longer maybe? Climb
> tower…adjust.  Meaure-rotate-measure again. Maybe we getting closer to
> optimum? shorter, test…longer test. Are we yet at the maximum F/B or can we
> get a bit more? Climb tower…readjust…etc. etc..  This is especially tedious
> and difficult with a narrow-band shortened low-band Yagi.
> I speak from experience. This method is a lot of work and can take many
> iterations and you will still not be sure.…been there done that!
> The other issue is aberrant ground reflections and wave angle
> considerations depending on your distance from the tower, Yagi height etc.
> My field measured polar plots often showed some funny things and pattern
> distortions.
>
> The method I describe in my video is MUCH easier, and leaves no doubt that
> the antenna is tuned as per your model. I have used it to tune both my
> 80-40M Yagis as well as the 160m parasitic array and subsequent on air test
> confirm they are optimally tuned.  In all cases tuning was quick and easy.
> I honestly cant imagine doing it by field strength testing!
> Understanding how the SWR bandwidth becomes more narrow as you approach
> the max gain point, and comparing this to your model, you can
> even “dial-in” the tuning more to be exactly where you want it.
>
> 73, de steve ve6wz
>
>
> > You should be able to tune up any 2 element array, whether parasitic
> > or driven, by simply putting a signal source behind it and adjusting
> > for max F/B.  Or putting the signal source in front and adjusting for
> > maximum gain.  No analyzer required.  Then,  you can substitute fixed
> components for the variable L's and C's if desired.  This method works even
> if the driven element is a shunt fed grounded tower.  Just use
> > the feed as it was when the tower was just a single vertical.
> >
> > After doing that, you can get out the analyzer and
> > measure the drive impedance of the phasing network and design a
> > simple matching network to go between it and the transmitter.
> >
> > BTW, parasitic arrays seem simpler, but driven arrays (especially
> > 2 element ones) have better F/B ratio ), and broader bandwidth,
> > AFAIK.  YMMV.
> >
> > 73
> > Rick N6RK
>
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Re: Topband: CAT6 Feed Line

[Guy Olinger K2AV]

Hi Mikek,

The trick is to remember that just one common mode block rarely does the
trick. Usually if it's bad the first one will make a difference. The second
maybe not at all. What happens with the second depends entirely on where it
is with respect to the first block.

The trick is to understand what happened when the first common mode block
was installed at the feed (isolation transformer in your case). That became
a high impedance, high voltage point or voltage node in the common mode
standing wave on the feedline, like the ends of the wire in a dipole. If at
1/8 or 1/4 wave away from the feed, there is no additional block, that
point with its common impedance to the ground, will become a low voltage or
current node in the common mode standing wave on the feedline. The way to
really get to the common mode, is 1/8 to 1/4 wavelength from the the
voltage is to put in another common mode block. Now BOTH ends of the common
mode between the two will want to be a voltage node. But since neither end
can pass much current now, NEITHER end can be a voltage node because
neither opposite end can be a current node.

You often hear the answer that the second common mode block made all the
difference. That's because it takes TWO blocks to insure that neither end
can pass current, so neither end has an opposite current node so it can be
a voltage node. Two blocks at 1/8 to 1/4 severely restricts the ability of
the blocked stretched conductor to carry current.

Some people will say to quickly ground coax shield away from an isolation
transformer. The problem with this is that it sinks common noise from the
house into the ground conductivity around the RX antenna.  Ground it for
electrical purposes where it goes into/comes out of the house. Then add a
common mode block on the antenna side of the grounding. You don't want
common mode current to have an easy current path to ground anywhere.

Hope that helped a bit.

73, Guy K2AV

On Tue, May 19, 2020 at 10:08 AM Mikek  wrote:

> Now that I have the CAT6 feed line ingress mostly tamed.
> (Installing the isolation transformer did that.)
> What methods can I try to reduce the ingress even further?
>
>   I have tried coiling the CAT6, 15 turns in 8" coil. That increased
> the ingress. I have a huge Iron core toroid, 15 turns on that also
> increased ingress. (I know wrong material. but it was there)
>   I tried a much smaller CMC, it didn't help or hurt.
>
> So, What methods can I try to reduce the ingress even further?
>
>Mikek KF4ITA
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Re: Topband: KV4FZ from the eyes of the USVI

[Guy Olinger K2AV]

Thanks for the URL

73, Guy K2AV

On Mon, May 4, 2020 at 10:08 AM Edward Seeliger 
wrote:

> For a perspective on Herb - KV4FZ - from the eyes of those who knew him in
> the USVI, see this link:
>
> https://stthomassource.com/content/2020/05/03/activist-communicator-herb-schoenbohm-dies-at-84/
> Edd - KD5M
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Re: Topband: Measure dipole on ground to get VF of BOG.

[Guy Olinger K2AV]

Hi, Mikek,

BOGs have a very miscellaneous performance, some love 'em, some hate 'em,
nobody telling a lie. One part of a back yard can have a heated BOG
argument with a different part of the same back yard, both sides verified
with MEASUREMENTS. The secret has to do with the BOG in DOG disguise, or
BOG's DOG.

When BOGs are working right, they are very good at getting rid of local low
angle noise off the sides.

If you have modeled the pattern of a BOG, you will find that the pattern
varies with the ELECTRICAL length of the BOG. When the electrical length of
a BOG gets too long, the pattern can deteriorate to zero front to back
ratio. And if it gets longer yet, it can actually reverse to a back to
front ratio.

To derive a physical implementation of a BOG model that has generated a
good pattern, change the bog wire to a dipole (do not change the height or
ground characteristics). Remove all other wires, then measure the resonance
(the R component of R+jX, when X=0, not SWR)  of the wire fed as a dipole.
That is the BOG's DOG.

For one reasonable and fairly successful BOG design, that resonance for the
BOG's DOG is 1140 kHz for 1.83 MHz BOG design frequency. For a BOG, the end
termination is a good deal less significant than having the BOG's DOG at
1140 kHz.

You put down the DOG in the place you intend to install it, at the height
and relation to grass, dirt, etc, you intend to install the BOG, and with
the final site preparation already done. You prune the DOG to get 1140 kHz
resonance, and then solder and insulate the center to a single wire again,
and ONLY THEN add the feed and termination elements of the BOG.

In '09 a dozen or so of us MEASURED quite a number of 151 foot (46m) DOG's
in the counties around Raleigh/Durham/Chapel Hill. We found that the ground
was WILDLY variable in its effects on VF. VF was WILDLY variable from 45%
to 85%, sometimes WILDLY variable in the same back yard by rotating the dog
90 degrees about its center.

This nailed down the principle that a BOG must be set its length for the
particular VF at its EXACT placement, or suffer what for a long time has
been a history of mixed "great antenna", "awful antenna" reports without
rhyme or reason for the variance. No one size fits all unless large
variation in results is OK.

The VF also changes with moisture in the soil, meaning that unless in
perpetual arid conditions, it needs to be set in the area's damper
conditions. If a moist location has a dry spell threatening a contest
weekend, you can always go "water the BOG" with a bucket to return it to
installation day behavior. A little hard to do the other way around with a
hair dryer on a 100 yard long extension cord.  Also, as grass or leaves on
top "grow the BOG down" you can experience well-documented deterioration of
pattern, unless you maintain the BOG and its installation location in the
same condition as it was when installed.

You cannot reliably tune a BOG using SWR, quite contrary to
well-established successful technique with beverages. A BOG does not behave
like a beverage. The beverage paradigm has been monstrously overwhelmed by
the BOG's intimate relationship with the dirt.

Also remember that for most people a BOG is a LOW SIGNAL, negative gain rx
antenna, and often needs a preamp. Procedures dealing with common mode
noise on the feedline need to be followed, particularly using an isolation
transformer (primary and secondary no connection other than magnetic flux
and minor stray capacitance) and the feedline not grounded in the area of
the feed, or you can bury the BOG's lower signal in preventable noise.

73, Guy K2AV

On Sat, May 2, 2020 at 1:42 PM Mikek  wrote:

> I'm about to do some measurements on a BOG.
>   I've been a little slow getting things working, I've now got my inside
> and outside boxes assembled,
> I understand I can break the BOG in the middle and find resonant
> frequency as a dipole.
>  From that I can calculate the VF. I may leave this for a while and hope
> for rain to get some
> different measurements.
>   I also wonder about measurements, on the ground, at 1" above ground,
> and at 2" above ground. Is there any advantage to
> the pattern or signal strength. At 2" inches I could weed whip to keep
> it weed free.
>
>
>   On a second note, I'm building it long, for the AM band and
> considering using KD4Zs stretch modules (in my case shrink modules)
>   for 160M and 80M bands. Although I think I would just terminate
> instead of reflect.
>
>   Your thoughts? any good pages about the Dipole on ground measurements
> appreciated.
>
>  Mikek   KF4ITA
>
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Re: Topband: Anyone QRV in ND?

[Guy Olinger K2AV]

In the past two ARRL 160 and two CQ 160 CW contests, I worked the following
with ND in their exchange. I checked, they all have QRZ.com addresses in ND
as of today. I worked K0IDX in two contests, the others just in one:

N7IV
N0UD
K0YL
K0IDX

I'd get their email addresses and go beg.  Quick, before they pull up their
radials for plowing.

73, Guy K2AV

On Sat, Apr 4, 2020 at 11:37 AM  wrote:

> Ron, K0IDX in ND is still active on 160 I believe – try him at his QRZ
> address.
>   73 jay ny2ny
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Re: Topband: Ground Conductivity

[Guy Olinger K2AV]

Rudy is not the only one taking measurements.

I've been doing EZNEC since 1996 (v2) and NEC4/EZNEC Pro since 2002. The
latter cost me well over a thousand bucks, but has been well worth it in
the long run and then some. NEC4 does on the ground and under the ground in
a reliable way, but still does not match some aspects of reality. Rudy got
it to track in very confined circumstances, which by the way is a huge
clue. Rudy's confines are not available to most folks.

Back before we published on the FCP, we were trying to make sense of how
BOGs behaved, and decided on a plan to measure VF to either confirm or
blast a theory that the electrical length of a BOG varied enormously and
simply had to be taken into account if modeled dimensions were to be of any
use at all.

A lot of us roughly in the Raleigh area were putting a 151 foot (46m)
dipole on the ground (DOG) and taking measurements, frequency and R where
X=0 and ditto for X = +/- 25 ohms. About ten of us were taking measurements
in a roughly 100 mile radius around Raleigh. The 151 feet was to give an
even metric equivalent, and to get X=0 roughly in the 160 meter region.

The **measured**, not modeled, velocity factor (VF) of a DOG was anywhere
between 45 and 85 percent. The R at X=0 was anywhere from 80 to 200 ohms.
Very frequently various placements of the DOG on the same property made
maximal changes in the results. Rotating a DOG 90 degrees around its center
would sometimes make huge differences. A permanently set, frequently
measured DOG would have large variations with dampness of the general
weather pattern and under snow, etc, and exhibited the gradual change
"settling in" measured by Rudy.

This resulted in a realization that a BOG would have to be modeled for it's
electrical length, and adjusted somehow at the exact placement. E.g. if a
DOG is trimmed to get it's X=0 at 1142 kHz, and then soldered back together
and insulated at the center and grounds, terminations and cable only placed
when the end points that matched the model's electrical length were known.

The composition and behavior of ground varies wildly from place to place. A
very dense, uniform around the compass, and decently large ground radial
system will tame that. Elevated counterpoises will tame that to a lesser
degree, depending on as much independence from inducing ground as can be
managed. Or you can go horizontal and get into a different and more
friendly paradigm. Not so easy for that on 160.

I myself, and perhaps ten other NEC4 users I know of have tried to get NEC4
ground characteristics to match, with little or only isolated successes.
This is known well enough by the commercial AM BC antenna folk. In filings
the FCC will accept the NEC4 ground constant which generates the field
strength which matches the actual measured field strength after antenna
construction. Only the hams seem to think that the program has mastered the
phenomena. It has not.

It probably could be reprogrammed to deal with data from about a hundred
ground measurements in the antenna near field. But then the square and
cubic law aspects of the program run time would get in the way again, as
was critically still the case when those programs were developed.

Further there is an aspect to the skin effect which NONE of the programs
takes into effect.

At N4AF, where we were doing the NY4A multi contests, there was an
interesting SWR anomaly that would sometimes creep in. Howie had a monster
5 element 40m quad fixed on Europe, and hung across a 200 foot catenary
between two towers. The quad element centers were at 84 feet, so ground was
in play. Some early mornings, the SWR would rise to 1.5:1 from it's normal
1:1. It coincided with a still night and dew on the grass. That was when
the layer of air above the ground was at 100 percent humidity, which meant
that moisture from the ground was not percolating upward and being
evaporated into the air. With any wind, the ground close to surface would
have less moisture the closer to surface, and if it had been dry, a good
deal less. Less moisture, less conductivity.

Effectively, the height above actual RF ground had changed, or its
resistance had changed or some ghastly mathematical formula relating the
two had changed.

All the formulas about skin effect ASSUME uniform conductivity to a surface
which is bounded by an insulator. NOT a layer of a more resistive
conductor, and certainly not a conductor that gradually gets more resistive
as it gets drier as it approaches the surface, and also varying in a daily
or even hourly sense with the weather.

The problem for ground radials is that frustrating most-varying medium is
what the wire is on/in, and on/in at the point of most variance.

I'm to the place where I view those problems as something needing avoidance
altogether, IF I don't have the land and the copper to put down the
commercial standard. Sparse, too-small, irregular radials will NOT avoid
the near certain losses from that medium. Either go commercial 

Re: Topband: Slightly OT - amplifier noise

[Guy Olinger K2AV]

Depending on the exact circuit and device, to measure noise from the device
itself, don’t you have to terminate the inputs to put the normal impedance
on them? The circuits are often designed with the coax Z zero in mind.

73, Guy K2AV

On Mon, Mar 16, 2020 at 12:47 PM Steve London  wrote:

> This has been a very interesting thread - Thanks for all the input.
>
> Perhaps I have set my expectations too high.
>
> A typical application is on 15 meters, late in the opening, working JA's
> from
> here in SW New Mexico. Absent any local QRN, the band is very quiet. Any
> local
> noise covers the bottom layer of 5 watt JA's calling me.
>
> I did some more testing with the MFJ-1025. With no antennas connected, the
> box
> raises the noise floor about 10 dB, irrespective of the Aux Antenna Gain
> or the
> Main Antenna Gain. I haven't yet tried powering from a battery, to make
> sure the
> power supply isn't the source. Assuming the J310's are quiet, that leaves
> the
> 2N5109 emitter follower, or the back-to-back protection diodes. Might also
> try
> disconnecting the RF sense circuit.
>
> 73,
> Steve, N2IC
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Re: Topband: T Top Verticals and yagis

[Guy Olinger K2AV]

That’s an awful lot of effort just to keep a T top. There are a number of
effective alternatives to the traditional T top without the interaction
drawbacks. Inverted L is only the dirt simple one without the
skip-zone-making high angle hole in the pattern.

73, Guy K2AV

On Fri, Feb 28, 2020 at 9:46 AM W7RH  wrote:

> The discussion has involved horizontally polarized Yagis. Perhaps use a
> vertical 8 circle array on 40m! LOL And keep your T-Top!
>
> Bob, W7RH
>
> --
> W7RH DM35qj
>
> "It has become appallingly obvious that our technology has exceeded our
> humanity." - Albert Einstein
>
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Re: Topband: CQ WW Contest

[Guy Olinger K2AV]

Hi Roger,

Just want to be sure we are both talking about the weekend of 25, 26
January, 2020, the weekend of the 2020 CQ 160 CW contest. If so, I must
register my decidedly firm impression that was the best 160 meter weekend of
my lifetime, what has to be a counterpoint of the amazing 1958 sunspot
maximum.

In the contest I worked 1349 stations including 339 10 pointers (almost all
the 10 pointers were European), let's just say 300+ European stations. In
all of that I worked a 160 meter worked all states (48 CONUS + AK & HI),
plus 9 Canadian provinces, 78 countries ("country" per the contest rules).
That was a claimed score from the southeast USA (decidedly not the
EU-advantaged northeast US) of 752,780.

It was, by an enormous margin, my personal lifetime best for any 160 meter
contest. The antenna did work very well, but, seriously, could not possibly
have accounted for that bump up, nor for sure could my personal operating
skills.

Just think we need to leave room for the idea that maybe the band was a bit
better than "open".

Station here K3 + KPA1500, Inverted L over FCP, no RX antennas (working on
that), NOT a superstation.

Wowser, I wonder if we'll get that again before the sunspots start in
again. I can hope.

73, Guy K2AV

On Tue, Jan 28, 2020 at 3:27 PM Roger Kennedy 
wrote:

>
> Well conditions were reasonable over the weekend . . .
>
> I spent a total of about 3 hours on the band, and managed to work 48 NA
> stations through all the European QRM.
>
> I'm sure I would have worked a lot more, as I heard many others calling
> stations that were calling CQ . . . but I'm reluctant to put out a CQ call
> in a contest, as I don't want to work hundreds of Europeans (I'm up in the
> middle of the night to work some DX !)
>
> As I say, I wouldn't say conditions were particularly good, but the band
> was
> open.
>
>
> Roger G3YRO
>
>
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Topband: K2AV Trident L

[Guy Olinger K2AV]

Starting with a 160 inverted L/FCP, we first added 80 by tuning the aerial
wire/FCP as an end-fed half-wave L. That's been up, works very well, off
beta status. But 40 meters was always a killer. Many, many, many hours of
EZNEC runs chasing something to get 40 meters on the same aerial wire/FCP.
But no results worth the wire ,rope and insulators.

Just simply loading up the 160 L on 40 with a base network gave awful 40m
patterns and loss.

No more.

The answer is in k2av.com, version 2020.01.11. Click on Trident L 160+80+40
Aerial/FCP.  3/4 omni, if horizontal is bend at N, pulled to S, then NW and
NE are 4.9 dBi.

The Trident L article also includes downloadable plot files from the EZNEC
Pro/4 runs showing the gradual results from 40' to 70' vertical wire in the
Trident L. Any level of EZNEC can display the plot files, including the
free demo version. Instructions on how to do this are in the article.

We have several Trident L's going up around Raleigh as we work on the
antenna's experimental status.

Enjoy.

73, Guy K2AV
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Re: Topband: de n7dd

[Guy Olinger K2AV]

Issues of a fixed capacitor as seen in this thread have been a similar
problem for a network two-banding an 160m Inv L over FCP.

k2av.com has a section on this problem how to do 500 with three 170 pf
barrel style HEC caps. The section also has links to HEC reference material
on how to derate those capacitors, also links to a number of suppliers.
Click on green index button "160+80 on One L/FCP".  Do a find on "80M
Capacitor".

The calculations in the k2av.com text are at 3.5 MHz. The reference
material will need to be exercised for 1.8 MHz.

The HEC 170's seem fairly plentiful with better prices than other cap
values.

73, Guy K2AV

On Fri, Jan 10, 2020 at 2:22 PM Mike Waters  wrote:

> An air variable is exactly what I was thinking, Dave.
>
> My 160m inverted-L tuner uses just two air variables. I padded the HV
> variable with a small 100 pf N1500 (or two) doorknob with no problem.
>
> I use those same doorknobs as padders in my HB legal-limit amplifier, but
> they do cause the tuning to drift. :-(
>
> I have also seen fixed-value HV vacuum capacitors at hamfests.
>
> 73 Mike
> W0BTU
>
> On Thu, Jan 9, 2020, 3:15 PM David Olean  wrote:
>
> >
> >  ... What about an air variable in a wx proof box?
> >
> >
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Re: Topband: K9ay loop not performing

[Guy Olinger K2AV]

The need to disconnect the feedline shield is to block common mode signals.
A K9AY approved **EXCELLENT** common mode block (not a regular "balun" with
likely awful blocking on 160m), or (GASP) an isolation transformer will
take care.

In the case quoted, with the coax center contductor opened, the
stinky-on-160-blocking "balun" is how the noise gets in. Further since Pete
saw a 4 S unit drop by simply disconnecting the TX wire, it's likely that
his common-mode provision, even if not intended as such, would appear to be
satisfactory, and therefore a double pole relay (lot more expensive) is not
called for.

73, Guy K2AV


On Sun, Dec 8, 2019 at 7:30 AM Rob Atkinson  wrote:

> If you open the tx antenna feedline for rx, from my experience, you
> need to completely open the entire feedline, namely the coaxial cable
> shield as well as the center conductor.   coaxial relays that maintain
> conductivity of the shield when N.O. won't detune/isolate the tx
> antenna.  I use a pair of open frame relays for this.  Fortunately on
> 1800 kc the Z bump is almost nonexistent.   What will govern your
> choice of relay is tx power and tx time, and whether or not you
> require QSK.  I do not, but if you do, you may have to consider
> something like multiple paralleled reed relays tor speed and power, or
> vacuum relays.
>
>
> 73
> Rob
> K5UJ
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Re: Topband: K9ay loop not performing

[Guy Olinger K2AV]

Pete,

See RF parts.com, search vacuum relay VC2T-13.2.  SPDT will allow you to
change your mind about what state you want with no voltage to winding. And
you will not need to buy a 24 volt power supply.

Rated 12 kV will handle anything ham QRO. These are new, currentLy
manufactured items.

73, and Happy Holidays,

Guy K2AV

On Tue, Dec 10, 2019 at 11:31 AM N4ZR  wrote:

> Now that I've determined that my transmitting antenna must be
> disconnected, in order for my K9AY loop to work successfully, can anyone
> tell me what sort of ratings are required for the relay required to do
> this remotely?  I'm assuming a vacuum relay, but in looking at the MGS4U
> list of available SPST relays, there is a huge price range.  What sort
> of numbers should I be looking for, given 1.5 KW and location at the
> base of a quarter-wave inverted L.
>
> I also note that most of the relays listed have  26.5 volt coils.  Can
> anyone recommend an inexpensive 24-26 volt supply that I can use?
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at , now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
>
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Re: Topband: BOG Beverage on Ground Help

[Guy Olinger K2AV]

I agree with Bob. I think the name BOG is firmly entrenched, whatever the
electrical differences. Oh, I could propose a new name, but I doubt it
would ever stick.

I'll go back to my Otter/Platypus to propose a parable:

Suppose that the Platypus had instead gotten the name of Duckfaced Otter,
and that was firmly entrenched in the language regardless of the science
placing the Duckfaced in a different Latin-worded species.

Then on a reflector, an argument crops up, someone says that the Duckfaced
Otter lays eggs. Others deride that statement, saying everyone knows that
an Otter is a mammal, that mammals give live birth and Otters do not lay
eggs. Some, quite irritated, ask wouldn't the Duckfaced Otter have been
named differently if it was really that different? Probably because it was
named centuries before people knew it laid eggs.

In the science, the egg-laying, out of many differences, all by
itself would put the Duckfaced Otter into a different species, because such
differences are what define different species. Overall, most already know
that the Duckfaced Otter only *looks* like an otter, really isn't. But they
still call it the Duckfaced Otter because that's what the language calls
it. Who among us ever gets to successfully take on the language?

---End of Parable---

Beverage   Otter

On-ground Beverage Duckfaced Otter

Both are a longish  Both have brown
wire parallel to earth,  water repellent fur coat.
only used for RX.and love the water.

Isn't it really about time that the masses on the reflectors know that a
BOG has irritating issues that no up-in-the-air beverage has to design
around, but must be taken into account designing a BOG? That any Beverage
strategy has to be analyzed laying on the ground to see if it really
applies to a BOG?

The antenna category is Ground Low Velocity Factor. The short for that
could be GLVF, except we already call those -on-ground or OG. Dipole on
Ground is a DOG, Loop on Ground is a LOG, Beverage on ground is a BOG. In
this system "Beverage" is only one possible shape of the wire laying on the
ground. How a BOG behaves and how to engineer/model one is really only one
application of how OG behaves and how to engineer OG.

I think OG is just fine. I don't think OG needs a new name. Just remember
that BOG is only one shape instance of OG, and OG controls the engineering.

73, Guy K2AV

On Mon, Dec 2, 2019 at 6:38 PM Chortek, Robert L. <
robert.chor...@berliner.com> wrote:

> I don’t think it matters what label we use as long as we correctly
> understand its electrical properties.
>
> AA6VB
>
> Bob
> Robert L. Chortek
>
> > On Dec 2, 2019, at 3:13 PM, Mike Smith VE9AA  wrote:
> >
> > [External Email]
> >
> > K2AV says ".BOG is not a Beverage. So don't think about or treat a BOG
> like
> > a Beverage."
> >
> > 
> >
> >
> >
> >
> >
> > You seem pretty adamant about that Guy.
> >
> > What *SHOULD* we be calling it then please?
> >
> >
> >
> > Mike VE9AA
> >
> >
> >
> > Keswick Ridge, NB
> >
> >
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
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Re: Topband: BOG Beverage on Ground Help

[Guy Olinger K2AV]

BOG is not a Beverage. So don't think about or treat a BOG like a Beverage.
The relationship between a Beverage and a BOG is like the relationship
between an Otter and a Platypus. Both are aquatic mammals, but the Platypus
lays eggs and has other very un-Otter characteristics.

Early in the decade, a bunch of hams in the counties around Raleigh/Durham,
North Carolina, ran a bunch of Dipole on Ground (DOG) MEASUREMENTS, to try
and explain the vagaries of BOG behavior. MEASURED (not modeled) velocity
factors of a 151 foot (47m) DOG varied from 45% to 80%. In some cases
simply rotating the DOG around its center 90 degrees in the same spot
created very large changes in VF. This absolutely underscored the need to
install a BOG using a method accounting for the MODELED VF at the ACTUAL
site using the ACTUAL placement of the BOG. We also MEASURED variations in
VF with changes in moisture.

Most issues with BOG's relate to its severe closeness with ground. It
really does not behave at all like an up in the air beverage antenna.

As to modeling, that's the number one misunderstanding and/or omission in
thinking, which I hear over and over again:

The BOG's pattern depends on its ELECTRICAL length, not so much the
termination. SWR does not properly tune a BOG. Emphasis intended. The
incoming signal in the air can be going twice as fast as the signal on the
wire, in phase at one end of the wire and out-of-phase, cancelling at the
RX end of the wire. Beverages do not have such problems unless they are
very, very long and uncharacteristically low.

THE BOG'S PATTERN DEPENDS ON ITS ELECTRICAL LENGTH.

That, as a percentage of its physical length or Velocity Factor, can vary
WILDLY all over the map, explaining the WILD variation in result
satisfaction. And if that were not bad enough, VF can vary WILDLY with
changes in ground moisture content. It can vary with a sneaky slow change
as it grows down into the grass if it wasn't notched down to the dirt to
start with. It can change if leaves pile up on top of it. Again, all of
these are a problem because...

 THE BOG'S PATTERN DEPENDS ON ITS ELECTRICAL LENGTH.

You cannot model a BOG and directly use the modeled physical dimensions if
you are trying to optimize a pattern. Get the pattern you want in the
model, then model a DOG at the same physical height, wire size and physical
length as the BOG model, and use SWR or repeated SRC DAT's to find it's
resonance. That will tell you the ELECTRICAL LENGTH in the model and
therefore the self-resonance frequency needed to create the needed
electrical length in the actual physical BOG.

Then when you go to put down an actual BOG based on that model, do a DOG,
IN PLACE, EXACTLY WHERE, AND IN THE EXACT SAME MANNER YOU INTEND THE BOG TO
BE LEFT, trimming or extending the DOG to match the MODEL'S RESONANCE. Then
rewire the DOG's component wires into the BOG. Solder and insulate the
center, hook up the ends to termination, etc, but don't move or adjust the
length of the DOG wires for any reason. You should redo this exercise after
it's been there for a while to account for sink and cover, etc.

And remember, BOG's are a LOW SIGNAL antenna. Most BOGS really do need an
amplifier somewhere. They are superb at rejecting vertically polarized
local noise off the side.

That suggested for non-desert locations, that you install it with things
good and moist. If it's been dry for a while and it's VF is drifting, you
can always "water the BOG" to return it to installation moisture levels. If
you put it down with no leaves on top of it, you have to keep the leaves
blown off for operation. Don't lay it on the grass, and let it sink (get
closer to the dirt) over time. That will lower the VF and change the
electrical length, and detune it from the model.

You may have guessed that all the above makes it a single band antenna for
the desired prime pattern. Quite unlike the beverage that covers multiple
bands well.

Been there, done that, beaten by that, fussed at that, cussed that, cried
over that. Need to understand a BOG well and play by its rules.

73, Guy K2AV

On Sat, Nov 30, 2019 at 10:28 AM Grant Saviers  wrote:

> The goal is admirable.  I did some modeling of inductor shortened BOGS
> with EZNEC Pro4 and found it is extremely sensitive to height above
> ground.  A half an inch change in height can reverse the pattern. Thus,
> I consider it an impractical antenna given the nature of most real
> ground surfaces, i.e. exactly where is the modeled "perfectly flat
> ground of uniform properties".  This is in addition to the practical
> realization of the needed inductors.
>
> Grant KZ1W
>
> On 11/21/2019 19:09, K4SAV wrote:
> > Mikek said:
> > "I'd like to apply the loading to a BOG to slow the VF and make it seems
> > longer.
> >   ie. make a 80 meter BOG length work on 160 Meters. But then make the
> > reactance go away for 80 Meters
> >   My actual goal is to have a BOG that covers 500kHz to 4MHz. "
> >
> >
> > Mikek, I 

Re: Topband: AIM-4300 Discontinued

[Guy Olinger K2AV]

Hi Sam,

Not particularly surprising as technology has caught up and you can get a
two port VNA for $50. Chinese knockoff of a European device with an
absolutely ghastly user manual. But it shows no future for something
manufactured with parts and in a manner that requires a $500 price to
market at retail.

I'm not sure what the component or manufacturing breakthrough was, but it
will spread around, and the NanoVNA and stuff like it will doom the MFJ
259/269 series as well, and hopefully spells the doom of SWR as the only
concept considered by the mob in antenna design and tuning. Seeing both R
and X graphed all the time, with X going below the line, and everyone
looking at the same kind of dual display will advance the range and
accuracy of conversations about antennas. Text me a screen shot of your R &
X curves. Maybe we can bury SWR as the preeminent only thing thought and
talked about with 2 port VNA's that cost less than a family night out at a
restaurant

The NanoVNA actually is a two port VNA. Powered by L-Ion battery recharged
off USB port. Just terrible labeling and ghastly manual. Every human
factors aspect needs a lot of work.

I have one of those kinds of units, a MiniVNAPro, that also has bluetooth
connectivity and rechargeable internal Lithium battery. You don't need a
cord to it from a computer while it is testing. That's mandatory with some
of the stuff I'm doing. Progress keeps moving on.

73, Guy K2AV

On Fri, Oct 25, 2019 at 2:16 PM Sam Josuweit  wrote:

> I was just looking at Array Solutions web site to check on the price of an
> AIM 4300 and discovered the entire line of AIM analyzers has been
> discontinued. This is unfortunate as they are an awesome tool. Can anyone
> recommend a similar analyzer?
>
>
>
> Sam (N3XZ)
>
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: PreStew coming next weekend

[Guy Olinger K2AV]

Hi, Dave,

Can't know the final score until all the logs with their TX power levels
show up at Tree's place. What N1MM shows is as good as any beforehand. But
there is no way to know points for working an LP or QRP station until all
the logs are in Tree's data base. I don't know if the score sharing servers
work for the Stew Perry format.

So always be sure and take the time to work the weak ones in a Stew Perry.
Those LP and QRP stations you work increase your score when all the smoke
clears.

73, Guy K2AV

On Sun, Oct 13, 2019 at 3:31 PM Artek Manuals 
wrote:

> Ohhh can I get a copy of the log checking software?
>
>
> I like to know how I am doing as the test goes on
>
>
> Dave
> NR1DX
>
> On 10/13/2019 2:04 PM, Tree wrote:
> > I don't know about N1MM.  However, there is no need for your logging
> > program to do it.  The log checking software calculate the points for
> > everyone.
> >
> > Tree
> >
> > On Sun, Oct 13, 2019 at 10:56 AM Artek Manuals
> > mailto:manu...@artekmanuals.com>> wrote:
> >
> > Hi Tree
> >
> > Thanks for the reminder actually I had better VK/ZK openings this
> > summer on the EAST coast than I have for the last month 8^).
> > Europe and
> > Africa are definitely better though 8^)
> >
> > Does N1MM do the distance/score calculation for the SP? Must since
> > the
> > exchange is the grid square I assume it uses that to do the
> > calculation?
> >
> > Looking forward to giving my new BOGs and one E/W Beverage a work
> > out !
> >
> > Dave
> > NR1DX
> >
> >
> >
> >
> >
> > On 10/13/2019 12:12 PM, Tree wrote:
> > > The popular PreStew event is coming on Oct 19/20th next weekend
> > starting at
> > > 1500Z and running for 24 hours.
> > >
> > > The band has been improving with good signals from Europe into
> > West coats
> > > of North America and daily openings from VK to North America and
> > Europe.
> > >
> > > Full rules and previous results available at
> http://www.kkn.net/stew
> > >
> > > Tree N6TR
> > > _
> > > Searchable Archives: http://www.contesting.com/_topband -
> > Topband Reflector
> >
> > --
> > Dave
> > manu...@artekmanuals.com
> > www.ArtekManuals.com 
> >
> >
> > --
> > This email has been checked for viruses by Avast antivirus software.
> > https://www.avast.com/antivirus
> >
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> > Reflector
> >
>
> --
> Dave
> manu...@artekmanuals.com
> www.ArtekManuals.com
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: [TowerTalk] Skip Distance

[Guy Olinger K2AV]

Just remembered one other thing, the hours I use are SOLAR noon to SOLAR 2
pm. Where I live daylight time 10 am is 9 am standard time, and 8:50 am
Solar time.  In Lexington, Ky, USA that would be 8:23 AM. So during summer,
I wait until 1 pm to measure. HOWEVER...

Even then there can be residual propagation. I send a test CQ at 1.5 kw,
and look at what pops up on RBN. If it only hits W4KAZ, I'm fine. If I hit
KC4YVA, 149 miles away in Richmond, VA, I know there is reduced absorption
and the reading to KAZ could be affected. There have been days when at 2 pm
solar I was hitting YVA at 20 dB. Most days at 8:30 am solar, I'm still
hitting RBN's in Ohio over 400 miles away. So you can't just do it any day
at a certain time. You have to test for sky wave first.

73, Guy K2AV

On Fri, Sep 13, 2019 at 11:41 AM Clive GM3POI  wrote:

> Try it at midday.  73 Clive GM3POI
>
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Roger D
> Johnson
> Sent: 13 September 2019 10:11
> To: Towertalk Reflector; Top Band Reflector
> Subject: Re: Topband: [TowerTalk] Skip Distance
>
> These test were in late morning to early afternoon.
>
> 73, Roger
>
> On 9/12/2019 9:02 PM, Roger D Johnson wrote:
> > I've been running some tests on my 8 circle array with K1JB. Joe is 17
> miles
> > away and I sometimes notice deep fading on his signal. Makes plotting the
> > antenna pattern very difficult. Is it possible to have skywave
> contamination
> > at this short range?
> >
> > 73, Roger
> > ___
> >
> >
> >
> > ___
> > TowerTalk mailing list
> > towert...@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
>
> This email has been scanned by BullGuard antivirus protection.
> For more info visit www.bullguard.com
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
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>
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Re: Topband: Skip Distance

[Guy Olinger K2AV]

Decidedly possible.

W4KAZ RBN node is 7 miles away. There is skywave contamination almost every
evening with large drops. It can be increased or reduced by the choice of
antenna at the RX site, but not eliminated.

The largest signal to the RBN is usually high noon. That is fudged by wet
local conditions, but very obvious in long dry spells.

Why or how? No idea. Stuff I was taught all these years doesn't really
explain.

You can try your measurements at summer dry high noons part of a dry week.
Where I live that would improve your results. Can't be sure that
extrapolates to your location.

73, Guy K2AV

On Thu, Sep 12, 2019 at 9:02 PM Roger D Johnson  wrote:

> I've been running some tests on my 8 circle array with K1JB. Joe is 17
> miles
> away and I sometimes notice deep fading on his signal. Makes plotting the
> antenna pattern very difficult. Is it possible to have skywave
> contamination
> at this short range?
>
> 73, Roger
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
-- 
Sent via Gmail Mobile on my iPhone
_
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Re: Topband: Supplemental ground rod installation for existing 160m tower

[Guy Olinger K2AV]

Hi, Jeff,

A direct strike can easily overwhelm a single ground rod, not so much
because of the ground rod, but because of the resistivity of the
ground that is touching it. The condition of the total interface of
rod touching dirt limits it's current carrying capacity. If
sufficiently spread, a network of ground rods multiplies the current
carrying capacity, and divides the resistance of the total ground rods
to dirt interface. You also have the interface of the tower base to
ground, perhaps useful depending on exactly how that was done.

#18 can easily be popped by a strike, if left as the only other
interface to ground around an insufficient ground rod or rod array. If
this has been that way for a long period of years, you may in fact
have a lot of popped #18, where the discontinuity is actually out in
the wires. This is not helped by moisture induced surface corrosion of
the individual strands.

There is no guarantee that the pop would take place at the radial
connection ring. You may have places on the #18 where both wire and
insulation are evaporated into the soil. When strike current is moving
out a wire, you get a counter-EMF which starts to raise the voltage
across the insulation. The pop at the ring likely was current induced,
and pops out in wire would be voltage induced since the wire is
insulated.

A lot of folks poke at the FCC specification of bare #4 for commercial
radials, but as #4 is rated for bus to ground rods, it also cannot be
popped by diverted lightning. Pretty sure (!!) that hams are not
willing to put down 80 times 1/4 wave #4 for a ground field. That
leaves a quality ground rod field as the way to protect the #18 in the
radials.

73, Guy K2AV

On Thu, Sep 5, 2019 at 1:00 PM Jeff Blaine  wrote:
>
> I have a full size vertical built from 25G running against about 80 1/4
> WL radials - #18 insulated wire sewn into the ground an inch or two
> below ground.  There is a single ground rod next to the base but no
> other ground rods on this tower.
>
> We had a lot of lightning here last week and the tower took a hit which
> popped a wire off the matching net.  I am going to put a spark gap of
> some sort on that tower to help address that but it's got me wondering
> if I should also add in a set of ground rod.
>
> The other towers on the site have extensive ground rod structures.  The
> nearest tower to the 160m, for example, has 27 rods mounted along 9 bus
> runs.
>
> If rods are needed, does the existing ground radial screen offer me a
> discount on what is needed?I'm assuming that the existing radial
> field would provide some level of ground coupling for lightning and to
> get an equivalent level compared to the other tower.  Meaning somewhat
> less than 27 rods - when combined with the existing 80 1/4WL radial
> field - would be functionally the same as the other tower has.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: BOG height

[Guy Olinger K2AV]

Hi Mike, et al.

I have personal acquaintance and knowledge of a number of hams who have put
down a BOG that was anything but straight. Some with 90 degree bends,
another shaped like a Z, and less extreme bends. The end of those small
lot, weird property situational BOG attempts, is that a few didn't do much,
maybe nothing. But some significantly improved signal ratio of incoming
desired 160m signal to local noise. This appears to invoke a degree of
something clearly seen on straight BOGS where local noise from broadside
the BOG is reduced significantly. Theoretically some could object that
20-25 dB side rejection is reduced by a bend, and it surely IS reduced.
HOWEVER...

... And a big however, even if only 4-6 dB of the reduction remains, a
general reduction of 4 dB noise on a given 160 signal will make a big
difference in results, in who he hears and hears not. Theoretical thought
and practical thought sometimes give one different answers to "To Do or not
to Do, that is the question". Theoretical should serve the practical, not
the other way around.

Sometimes our beloved reflector mob is inclined to entirely dismiss
anecdotal material from the field, dismiss anything that was not derived
from a controlled lab-style experiment. The lab-style experiment is good to
establish behaviors as fact, principles to use. BUT the anecdotal tells us
how it plays in the real world, where the lab experiment derived
implementation rules are often simply not possible.

In the end, one needs to understand the factors that bear upon performance,
AND understand them WELL, but then just go try stuff out, even if some
aspects of the lab version have to be bent or ignored. Try things.
Personally I will take 4-6 dB improvement on hearing Europe, and it will
show up in my contest scores.

73, Guy K2AV

On Sun, Aug 4, 2019 at 1:59 PM Mike Waters  wrote:

> Based on questions I've received over the years from hams who found my
> Beverage antenna page, there is an an additional problem.
>
> Some hams just do not grasp that:
> (1) Beverages are directional, like a Yagi is.
> (2) A Beverage has to be reasonably straight. Dozens of folks want to put
> it over an existing fence, where it winds up being an L or U shape.
>
> 73, Mike
> www.w0btu.com
>
> On Sun, Aug 4, 2019, 12:34 PM FZ Bruce  wrote:
>
> > ...
> > The problem with the BOG is not the antenna, but new users who try to
> > use above ground Beverage information to make it work..
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: BOG height

[Guy Olinger K2AV]

Hi, Ed,

You're on the right track.

A "beverage" ON the ground really is NOT a beverage.  For two things to be
called the same genus, they need to have most everything in common. This is
true of big yagis, little yagis, short yagis, long yagis, trapped yagis,
linear loaded yagis, end loaded yagis, moxons, yagis at 30 feet and yagis
at 200 feet, etc. One program optimizes them all. A yagi is a yagi, is a
yagi, is a yagi, and all of them have a ton of yagi-ness held in common.
Simply not so BOG vs. beverage.

Creating beverage advice from one particulars person's wire down close to
or on the ground at their particular property, may be simply and totally
wrong for someone else. The normal beverage tuning instructions, usually OK
for wires a foot off the ground and maybe even OK to some degree for four
inches, simply do not apply if the wire is actually laying on the ground.

A regular beverage has a decent RX signal strength. To be truthful, a
**real** BOG needs a remote amplifier, because its output is way down from
a real beverage. Get this much straight: an actual BOG is a LOW output
antenna, period. The way to improve a BOG's signal output is add an amp
(best remote), or escape BOG-iness and lift it off the ground.

If you model a real BOG, you find that beyond an ELECTRICAL half wave ON
THE WIRE, or two hundred something feet on 160, extending the BOG wire will
start to REVERSE the pattern. No real beverage ever does that. Just some
beverage lengths are bit better than others FOR REAL BEVERAGES. A BOG is a
single band antenna for optimums. It will hear stuff on other bands, but
forget a designed pattern like you have on a beverage for several bands,
that work WELL on several bands.

If you are even two inches above actual ground, laying on top of grass, you
are blending the very different worlds of pure BOG and pure beverage. If
you are at two inches, you are at a poor place to advise either owners of
pure BOG's or pure beverages. The great problem is that exactly which type
you are closer to depends on the vagaries of the location-specific ground
underneath.

These vagaries wander HUGELY ( I'm talking about an actually carefully
measured  wandering HUGELY) depending on individual properties.
Based on those **measurements** it is a normal outcome that one end of the
wire could be more BOG and the other end of the same wire could be more
beverage, and even vary more depending on whether it rained in the last few
days (or weeks depending on the local and natural drainage of the soil).

It is clear reading a lot of the posts on BOG's from the last week or two,
that a lot of users were expecting greater signal output. Don't. A REAL
*BOG* that was laid down, notched in the grass down to the actual ground
surface, to get it out of sight and safe from lawn mowers, WILL sound MUCH
better to the ear if it has an amp. Otherwise, a BOG is a LOW LEVEL RX
antenna.

IN GENERAL, a real BOG needs an amplifier, will usually wind up somewhere
180 to 230 feet if you want front to back, and it's great advantage is that
it can't be mowed, snagged by galloping deer, have tree branches knock it
down, be seen by unfriendly neighbors and it will do roughly as well as a
single direction K9AY, but without the AY's ugly wires above the ground, IF
it's amplified. If the feed circuitry is done correctly, a BOG will be
wonderful at reducing local noise off the sides.

You will increase signal level significantly by getting it up an inch or
two on top of the grass, but it ain't a pure BOG anymore, the VF is
increased significantly, and then it needs more length to be optimum at two
inches. And you will still not be able to tune it smartly like a beverage
using SWR to the terminating resistor.

BOGs are a cantankerous RX antenna. You can throw a 250' wire down on top
of the lawn and take it up after the contest. In normal (not super quiet)
settings it WILL hear a lot of signals better than the inverted L. Just
understand that is NOT a design antenna, and was not optimized, did not
have the best signal to noise of a designed-for-location BOG antenna, and
was not as good as a beverage.

We know what the issues are, but new-comers to the BOG idea just don't know
the vagaries and how to squeeze the best out of on THEIR property.

The category is Ground Low Velocity Factor (GLVF) antennas. DOGs, LOGs and
BOGs. If they're up in the air, even two inches, they're likely NOT GLVF.
GLVF are low output RX antennas. If you are looking for high signal output
from the antenna without an amplifier, just forget GLVF.

Been there, done all of that.

73, Guy K2AV


On Thu, Aug 1, 2019 at 2:57 PM Ed Sawyer  wrote:

> Isn't  BOG still a beverage just with more ground coupling loss because its
> literally "on the ground"?  So the typical answer on beverages seems to be
> that 4 - 10 ft above the ground is low enough to eliminate the undesired
> noise but high enough to reduce the losses from being too low to the
> ground.
> A BOG is a beverage 

Re: Topband: FCP vs Gull Wing Elevated Radials

[Guy Olinger K2AV]

Hi Jerry,

65% is in the wheelhouse for DOG VF's. 400 to 600 ohms seems high. In the
12 county area around Raleigh/Durham/Chapel Hill, we measured 120 - 200
ohms resonant R.

The variation you experienced, and also high R readings could be explained
by a few nicks in the wire insulation toward the ends, which could have
been there to start with, or perhaps you experienced critter nibble, or
perhaps the ends were inadequately insulated from ground contact or the
elements.

DOG conductor in contact with ground moisture near the ends could
completely skewer results. That's an electrical 1/4 wave between center and
either end of the DOG. Inadvertently grounding an end will be transformed
around the surge impedance of the wire to a quite higher impedance at
center. An inadvertent partial grounding near the ends along with variation
in ground surface moisture would explain erratic observations of high R and
no resonance.

73  & Good Luck,
Guy K2AV

On Fri, Jul 26, 2019 at 10:34 PM K4SAV  wrote:

> K2AV said:
> "Measured resonance of a fixed length gave us velocity factor (VF) and
> other data. VF's based on those measurements ranged from 45% to 85%.
> That huge variability certainly explained the BOG experience, and
> suggested a solution, but that's another subject."
>
>
> When I did those tests at my house the velocity factor of a dipole on
> the ground was usually about 65% but many times there was no resonance
> at all, so no way to calculate velocity factor.  Total impedance was
> usually 400 to 600 ohms but resistance and reactance were all over the
> place.  That dipole was tested on the ground at various times over a one
> month period and never moved.  I can only guess that must have been due
> to variations in ground moisture content.
>
> I was also trying to use that data to help explain BOG performance, but
> I didn't have much success.
>
> Jerry, K4SAV
>
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Re: Topband: FCP vs Gull Wing Elevated Radials

[Guy Olinger K2AV]

Hi Wes,

Thanks for posting up the Severns material. I had started looking for that,
but without memory of exact words (which makes searching difficult), and
without absolute certainty that Rudy was who I heard it from. You likely
saved me an entire working day. If you're ever in the area, that's worth
free pizza and beer and a no-cost friendly guest bedroom accommodation
instead of a motel.

Rudy's contention:

"Confirmation of the NEC predictions was very satisfying but that work must
not be taken uncritically! My articles on that work failed to emphasize how
prone to
asymmetric radial currents and degraded performance the 4-radial elevated
system is. You cannot just throw up any four radials and get the expected
results."

... is oddly separately confirmed by research done by a group of hams in
the North Carolina Triangle area back in 2009. The task was to get an edge
on the highly erratic success/failure of BOG's. We were examining velocity
factor variation in an insulated dipole on ground (DOG) at various points
in our region. The DOG was 151 ft or 47m, picked for round numbers in
length and a probable resonance in or near 160 meters accounting for VF.

Measured resonance of a fixed length gave us velocity factor (VF) and other
data. VF's based on those measurements ranged from 45% to 85%. That huge
variability certainly explained the BOG experience, and suggested a
solution, but that's another subject.

To underscore Rudy's assertion that local in-ground and other influence can
screw up four raised 1/4 wave radials, I offer the DOG VF's, highly
variable in different spots across the region, and in cases highly variable
on the same property. The latter included a few where rotating the DOG 90
degrees about its center produced different VF's, varying 20% in one case.
This was accompanied by the owner's assertion that there was nothing buried
out there he knew about (pipes, electrical or phone feed, etc) and there
had never been a septic field. One feature of this area is veins of sand,
like fingers, near the surface bounded by hard-pan clay. One of these, with
its water content, would have a considerably different effect if a wire ran
across it, than if the wire ran parallel. And it would detune a BOG
specifically tuned to the ground underneath, if the water table dropped and
the sand finger drained out.

So to a lesser degree, but still with effect, similarly oriented 4 x 1/4
wave elevated radials (over that exact spot exposed by the DOG) will have
dissimilar resonances, and the old practice of resonating a PAIR or radials
still would not deal if the variable situation was all under just one of
the radials. The radials would have to be resonated individually with a
single-ended test, largely unfamiliar and requiring a made up testing
adapter and a graphing analyst that can display proper sign of reactance.
Even after that, there still could be differences in ground induction which
could not be adjusted out, causing differing R across the radials even
after X was adjusted to zero.

There is a certain amount of net RF field at ground that is minimized by a
"pure" 4 x 1/4 system. However, if the radials vary in X and/or R, then the
individual field phases at ground shift, and the net RF field under the
radials increases, increasing ground losses. The resulting reactance at
feed can introduce losses on common ferrite blocking devices. Blocking
device and common mode losses can be reduced or eliminated by an Isolation
Transformer, but the ground losses remain.

This is NOT to say don't do it, but if all the potential loss factors for
various counterpoises are considered on a particular ham's property, then
an informed choice can at least optimize to the degree possible. But by all
means put something up and get on the air.

To the degree I can tell, ON4UN's 4 x 1/8 wave elevated radials will always
beat out 4 x 1/4 elevated. At the same height and over the same center, the
4 x 1/8 must have only 1/5 the counterpoise ground power loss in watts of 4
x 1/4.  Just be sure to use an isolation transformer with the 4 x 1/8 so
you can use that coil to center the SWR (what everyone does anyway) without
the penalty of common mode and blocking device loss. Connect the radial
center point to the "FCP" connection on an isolation transformer.

The 1/8 wave is not a resonance point or magic length like 1/4 wave. 1/8
wave-ish will always have some degree of reactance. One can make them
uniformly a little shorter to deal with mounting points and keep all the
radial ends in the clear. You just need a little more coil to resonate the
whole thing.

To agree with Wes, gull wings do have an immutable specific loss issue,
which ought to discourage their use. The loss requires technical
explanation, comparative modeling and illustrations to clarify the issue.
The short answer is don't use gull wings, and the long answer I will have
to post on k2av.com in a new section, when I can get to it.

73, Guy K2AV

On Thu, Jul 25, 2019 at 

Re: Topband: RFI on TB

[Guy Olinger K2AV]

Hi Mark,

Response to David farther down.

Short answer:  Just one relay, really.

Long answer:

There is a lot of misinformation about FCP's floating around out there,
essentially because most don't know anything at all about FCP's and a
certain few of those keep talking anyway. I don't have a lot of sympathy,
because access to k2av.com is without charge, no entrance exams, and no
passport inspection. International readers constitute the majority of
12,400+ unique readers on k2av.com since September 2017, and they seem to
do well enough with their English skills or Google Translate.

What you have read about separately disconnecting the FCP is hocus for two
reasons:

1)

**IF** you **ARE** using the specified isolation transformer (IsoT) or a
close imitation per the specs on k2av.com, then when the Inv L is
disconnected from the IsoT by a relay, the FCP is ALSO effectively
disconnected.

With the relay open, no signal current can flow through the IsoT antenna
side winding, nothing to flow INTO. If no current in the primary, the
effective R terminating the FCP is very high, nearly as high as it is for
the Inv L.

If you are using some alternate feed system because you don't like IsoT's
for whatever reason, then the answer depends on what you did instead of the
k2av.com specs.

2)

In and of itself, the FCP is really, really, really bad at radiating to the
far field. That's 10 dB per "really". An FCP is a counterpoise, that is to
say an energy reservoir and an awful radiator. Model a pair of FCP's in
series, in free space, at right angles with centers right above one
another. The folding trick employed by an FCP is so good, that it radiates
between -29 and -31 dBi to the far field depending on exactly how the wires
are run. Yes that's MINUS 29 dBi to MINUS 31 dBi (EZNEC Pro/4 v.6, NEC4.2
double precision engine). Let's call that -30 dBi because 1/1000 is
convenient for arithmetic.

If you could get a pair of FCP's into low earth orbit and load up 1500
watts into them, only 1/1000 of that would be radiated as RF. That's 1.5
watts radiated RF and 1498.5 watts radiated as heat from the wire
resistance of the FCP's.

If it is bad at radiating RF, it follows that it will be doubly bad at
re-radiation. To re-radiate, it must first receive. As bad as it is at
radiating, according to physics, it will equally be at receiving. So first
it receives poorly, further diminished by poorly radiating, hence doubly
bad at re-radiation.

73, Guy K2AV

--

Hi, David

RX antennas being affected by re-radiation from a TX antenna is indeed very
much case-by-case, to use a term from earlier in this thread. But the test
is easy. Don't start by installing the relay. The test is too easy.

Find a noisy place on your RX antenna. Somehow get that measured. I'd use
my P3 in various modes. Get your measurements/snapshots, etc.  Then real
quick run out and disconnect the L from the IsoT. Run real quick back in.
Re-listen, re-measure and compare to see if the noise went down. Repeat
this test a good number of times on different days, different conditions,
different orientations, different times of day, etc.

Only start on the relay business if you have a benefit in hand that means
something to YOU,  that is actually improved to a satisfactory degree by
disconnecting the L from the Iso T.

Operating with it is tricky because you don't want your expensive
transceiver/amp transmitting into an open. It's also not good for the relay
contacts to "hot switch". So whatever you might do has to have switching
solved day one.

But it's worth mentioning, and worth testing. Not intended to discourage
getting RX antenna.

73, Guy K2AV
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Re: Topband: RFI on TB

[Guy Olinger K2AV]

I gotta agree with Rob. An inverted L aerial wire will hear ALL the noise
that is around. Mine sure does. RX antenna will help enormously if there is
a place to put one that does not get the noise second hand off the L. Not
enough room? A bit complicated, but "repeated" noise off the L can be dealt
with.

The worst noises around here heard on my L were all repaired by the power
company. The nastiest noise was very hard to find, I actually never "found"
it by looking for it. Noise turned out to be from a bad splice in an
underground 13 kV cable going from the 13 kV delta overhead out on US 64 to
the transformer for my eastern neighbor and next house over. It would come
and go with extended cold weather, but never would correlate to sunlight or
darkness. I would hear it next to my transformer walking around with my
battery K2 and a rubber ducky. It would never locate to up on a pole (only
power noise that didn't).

Finally the splice hard-arced, exploding the fuse up on the pole for the
neighbor's 13 kV feed, and taking those two houses off the grid. The noise
went away with the cannon shot noise. Blessed quiet on 160 and 80. I had
put up with that for almost four years.

In the end, Duke Energy completely reran his AND my buried 13kV lines, and
replaced his transformer. 35 years in the ground, 35 year old cable design
and materials, and deficient in THEIR opinion. Was really fun to watch them
use this super-neat burrowing setup that went right UNDER the woods and the
creek (whole other story). Now I can hear the lesser noises on my L from
all over Apex and Cary :>)  Need RX antenna for sure. That way I don't have
to listen to the Cary, NC noise (NE) at the same time as the generally
closer and louder Apex, NC noise (S, SE).

73, Guy K2AV

On Tue, Jul 23, 2019 at 9:37 AM Rob Atkinson  wrote:

> > Over past few months, I have picked up an S5-S7 noise signature on my TB
> inv
> > L antenna with K2AV FCP system.
>
> I would not use an inverted L for receiving.  Unusable for rx at my
> QTH but FB for transmitting.
>
> 73
> Rob
> K5UJ
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Re: Topband: Fwd: ARRL DXCC - 160 Meters OK1YQ (OK1RD) Legitimacy???!!!

[Guy Olinger K2AV]

It does seem, at the moment not being entirely wrapped up in ham
radio, that there certainly is the analogue of OK1YQ in just about
every realm of life. I can think of a few names that I personally
found intensely irritating in the particular circumstances. So I DO
understand the pique. When will the 

Re: Topband: Topband Phenomenon

[Guy Olinger K2AV]

For 160 meters don’t think of a jet as a reflecting surface. Try “thick
wire”.  Particularly one in a tight turn and wings significantly vertical.

73, Guy K2AV

On Sun, Feb 3, 2019 at 2:10 PM Paul Kiesel via Topband <
topband@contesting.com> wrote:

>  I don't have an explanation for this, but I had a similar experience
> during the contest. My receiveantenna is an unterminated BOG running
> alongside the road in front. I struggled to get F4HEC's call because he was
> so weak. He persisted and I finally got it. He was the first European that
> I heard in the contest. When we finished the QSO, EI0R dumped his call and
> he was 579. Unbelievable because I almost never hear Europe on 160 CW. I
> gave him a report and turned it back. By then he was barely copyable as his
> signal had dropped back down to the noise floor and I never heard him
> again. I managed to work several other Europeans whose calls I had to work
> at digging out. I would say conditions were generally good for me to hear
> those European stations, but the momentary signal from EI0R was very strong
> and unexpected.
> 73, Paul K7CW
>
> On Sunday, February 3, 2019, 9:38:50 AM PST, Dan Atchison via Topband <
> topband@contesting.com> wrote:
>
>  During the CQ WW 160 CW contest a week ago while operating at the N1LN
> M/S station, I happened to be in a fantastic run of EU.
>
> On one and only one QSO, I worked a "G" station whose callsign's last
> suffix letter was at least 20dB stronger than the rest of his call.  I
> mentioned this to NR4M while discussing the contest with Steve at the
> Richmond Frostfest and he said he experienced the same on one occasion;
> he thought meteor and I was thinking airplane.
>
> Anyone else experience this on topband and if so, have a "scientific"
> explanation?
>
> 73,
> Dan -- N3ND
> _
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>
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>
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Re: Topband: Updated K9YC common-mode choke PDF now available

[Guy Olinger K2AV]

I would not repeatedly bend any coax with a solid center conductor. Which
leaves RG142 for permanent routing. Jumpers to and from back of TXR and
amps etc are always RG400. Windings on cores are always RG400. RG400 shield
weave and center conductor made of very fine strands of silver coated
copper.

On K9YC’s latest cookbook he only specifies RG400. Do it right, do it once,
happily keep it.

RG400 can usually be had in useful lengths off EBay for half retail or
better.  The stuff almost never goes bad. So these are safe buys.

There are a lot of jumpers listed. I can sometimes get the stuff with a
needed connector already installed.

73, Guy K2AV

On Wed, Jan 23, 2019 at 8:07 AM MU 4CX250B <4cx2...@miamioh.edu> wrote:

> Very interesting, Jim. I wasn't familiar with RG-400, but I've used
> RG-142B for years. I compared the specs and found they're virtually
> identical, the only significant difference being that RG-400 has a
> stranded center conductor, while RG-142B has a solid steel
> (silver-plated) center conductor. They both have a 1 inch minimum
> bending radius (for repeated bending), but I imagine the RG-400 Is
> slightly more flexible and the RG142B is slightly stronger. At GHz
> frequencies, the RG142B has slightly lower loss. They both have
> excellent high temperature properties. If you buy it new from a
> distributor, either will cost about $5 a foot.
> 73,
> Jim w8zr
>
> Sent from my iPad
>
> > On Jan 22, 2019, at 6:42 PM, Mike Waters  wrote:
> >
> > -- Forwarded message -
> > From: Jim Brown 
> > Date: Mon, Jan 21, 2019, 11:36 PM
> > Subject: Re: Topband: Inverted L improvements - Part 3 (now with data)
> > To: Mike Waters 
> >
> > After nearly a year of work, I published a new "cookbook" last month.
> > For reasons that are detailed in the accompanying text, I no longer
> > recommend coax wound through multiple cores.
> >
> > The short answer for "why not?" is that it's simply not practical to wind
> > chokes that way and get anything close to the same result every time --
> > turns must go through the core in the same order, a scrambled turn
> cancels
> > a turn, turn diameter matters a lot, and so on.
> >
> > The new cookbook uses RG400, 12-2 Teflon/silver pairs, or 12/2 THHN or NM
> > pairs, all tightly wound around a single core.  There are recommendations
> > for chokes in series to increase power handling. There is also data for
> the
> > new 4-in o.d. supersized toroids, which are great for 160M.
> > k9yc.com/2018Cookbook.pdf
> >
> > 73, Jim K9YC
> > _
> > Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
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Re: Topband: FT-8

[Guy Olinger K2AV]

>
>
> -Original Message-
> From: w5zn 
> .snip
> Last weekend leading up to and during CQWW 160, all of the FT8 folks
> bitterly complained that the CW guys had taken over the entire band and
> destroyed FT8.
> .snip


In the US anyway, it was pretty clear to me that folks were steering clear
of 1840 thru and including 1843. But contesters were operating at 1839.5
and 1839.7 and 1844. The FT8 signals did not seem to be occupying close to
the edges though. Can't speak to what was going on in Europe.

There *were* some absolutely bodacious signals in the contest, a lot of
them. 20 or 30 over S9 on a calibrated K3. All the way, 1800 to 1840, 1845
to 1875. Think the SSB guys that live on 1850 and 1847 LSB were hearing a
lot of CW, and probably just turned on their autonotch.

I do think some cheap front ends, or too broad IF's may have been
absolutely CRUSHED by the sum RF signal voltage on the band. The answer
there, as always when one needs a clear 10 kHz to keep front end or IF's
from going mush, is to get a modern receiver. The K3 is into its 11th year
since release. Time enough to modernize a bit.

I thought it was rather decent of the boys to stay away from the FT8 slot.

73, Guy K2AV
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Re: Topband: Inverted L improvements - Part 3 (now with data)

[Guy Olinger K2AV]

What is missing from that discussion about a maximized use of a given
investment, is whether that investment however well maximized, is in fact
adequate for the particular ground characteristics and circumstances.

Four rotten eggs will deliver a rotten omelette no matter what you mix in
or how neatly it’s served up.

In seriously poor ground, the total copper in the radials needs to be
enough for full size, dense and uniform all around. A maximized inadequate
is still inadequate.

Sparse, undersized, or irregular ground radials do not do it for poor
ground.

His results with shorter radials suspiciously point to poor ground or
perhaps a local loss issue not yet identified.

He inserted a K9YC design choke at feedpoint and his R went up, indicating
that the earlier measurement was lowered by something shunting down the
true R of the radials.

73, Guy K2AV

On Tue, Jan 22, 2019 at 10:31 PM Chortek, Robert L. <
robert.chor...@berliner.com> wrote:

> Exactly!
>
> Sent from my iPhone
>
> > On Jan 22, 2019, at 7:25 PM, Grant Saviers  wrote:
> >
> > Al Christman K3LC thoroughly sliced and diced the tradeoffs of number vs
> length for given total wire investment is his Mar/Apr 2004 NCJ paper.
> >
> > N6LF also has a lot to say.
> >
> > Grant KZ1W
> >
> >> On 1/22/2019 16:11 PM, Chortek, Robert L. wrote:
> >> “Wes cut his radial length to match the vertical L section height (see
> N6LF
> >>> reference).  He didn't reduce the number of radials.”
> >> I didn’t think it was the “shortening” OF the length of the radials
> that would improve performance e.g. going from 10 125’ radials to 10 55’
> radials (in the case of a 55’ vertical); rather, it was the fact that 10x
> 125’ of wire could be better employed to increase the number of radials,
> albeit resulting in shorter radials, that decreases the ground loss (since
> most is nearer the base of the vertical).  If I’m correct, then shortening
> a given number of radials should decrease loss or improve performance
> >> 73,
> >> Bob AA6VB
> >> _
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Re: Topband: Inverted L improvements - Part 3 (now with data)

[Guy Olinger K2AV]

Have to pay attention to everything he is reporting. He added a feedpoint
choke per K9YC at the same time. Which may, depending on the physical
connections at his feedpoint, have removed the feedline shield as an
alternate “radial” in parallel with the increasing but still not full size
radial system.

That indicates that his ground characteristics could be well into the
“poor” end of the range where ground radial deficiencies are multiplied and
emphasized.

His SWR bandwidth narrowed slightly. Leaving a strong possibility that
there was an improvement in desired radiated pattern.

There remains the question of every conductor in a 250 foot radius,
including a tower? There remains the question of large dielectric masses
close by.

73, Guy K2AV
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Re: Topband: Inverted L improvements - Part 3 (now with data)

[Guy Olinger K2AV]

Hi, Fred. You said:

"Guy K2AV I'm guessing you don't like rg58 because of the center conductor
moving outwards??"

Nope.  :>))   RG58 is not RG400. That's why I don't like RG58.

RG400 is what should be used for winding coax on toroids. RG400 is a
currently manufactured item. It is INTENDED to handle sharp bends as found
in aircraft wiring harnesses (and therefore also handle being wound on
toroids). The center conductor is silvered stranded copper, the dielectric
is PTFE (Teflon), the shield is TWO dense woven layers of silvered copper
braid, and the jacket is PTFE.

RG400 is rated to 7 kW.

RG400 is Mil Spec. MIL-C-17 27478. Which means that if your house blows up
from a gas explosion, the RG400 will still be there working when the fire
is put out.

Essentially it never ever goes bad or weird unless catastrophically
treated, like crushed with a hammer, nailed through, ends submerged in
battery acid, or used as a tow rope for something heavy. I have one piece
of RG400 that was inappropriately used to arrest the fall of and suspend a
linear amp in mid-air. The coax still works, but it looks funny, and it
wasn't 50 ohms any more. A Chinese finger trap on the dielectric.

The silvered copper conductors in the double shields and stranded copper
center conductor will not deteriorate from occasional moist air in the coax
and convert it to many small conductors with performance changes, because
silver oxide is conductive.

The dense silvered copper shield weave, with two layers of shield weave in
RG400, makes for extremely good shielding. A lot of RG58 is cr*p shielding,
sparse enough to see through, sparse to maximize profit.

The PTFE in the jacket and dielectric is a low loss material, will not
deteriorate from ultraviolet. PTFE will not gradually shrink or crack by
leaching its chemical components.

The jacket and dielectric will not melt and ruin a connector when you
solder it, or when you forget it's there and put 1500 watts on it.

PTFE is a highly robust and predictable material. The PVC jacket
formulation on RG58 could be just about anything.

People have discovered that jumpers and leftover pieces of RG400 can be
sold on eBay. So you can pick up a ten foot piece of RG400 for less than
retail. I like the pieces with a male BNC on one end. I hate doing BNC
connectors. Brand-new coils of 100' plus can occasionally be had for as
little as 1.80 USD per foot, and regularly for 2.30 USD per foot, on eBay.

For all intents and purposes, a toroid wound with RG400 is a permanent
device, lifetime depending on the toroid instead of the coax.

You should buy enough RG400 so RG400 is the small coax that's "laying
around" and still good as new to do a project with, even if you bought it
20 years ago.

You can put your lifetime stash of RG400 in your will, and leave it to a
younger local ham, who will appreciate it.  :>))

RG400 is also K9YC's choice in his new
http://audiosystemsgroup.com/2018Cookbook.pdf. Check out the monster common
mode blocking choke wound with 23 turns of RG400 over a 4" OD, 3" ID, inch
thick #31 ferrite toroid. THAT'S a choke. 17K ohms resistive on 160.

73, Guy K2AV

On Sun, Jan 20, 2019 at 12:36 PM  wrote:

> Hello everyone.
>
> I also trying to improve things here on 160 and other bands.
> Going to make a few chokes.
> I have wound 8 turns thru 2.4 x2 31 mix but haven't seen any real
> improvement.
> Trying to get rid of some birdies.
>
> Guy K2AV I'm guessing you don't like rg58 because of the center conductor
> moving outwards??
>
> 73 Fred KB4QZH
>
>
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Re: Topband: Inverted L improvements - Part 3 (now with data)

[Guy Olinger K2AV]

Hi Todd,

Have a look at the calculator at
https://chemandy.com/calculators/return-loss-and-mismatch-calculator.htm

This calculator allows me to compute the SWR for your data points, as if
the Z zero of the meter was 32 ohms. This is important because so many
excellent antennas exhibit raw feed R between 15 and 35 ohms. This exercise
will give me SWR numbers the same as if I had put a 32 ohm to 50 ohm unun
in front of your 50 ohm SWR meter. Using the calculator gives a revised and
normalized table:

1820  1.61  29.1  -14.3
1840  1.20  31.0  -5.7
1850  1.04  32.0  -1.3
1860  1.12  33.0   3.6
1880  1.49  35.3   13.0
1900  1.95  38  22.9

This allows me to determine matched to 50 ohm line 1.5:1 SWR points at 1825
and 1880 or a 1.5:1 bandwidth of 55 kHz. A good guess would be that the 2:1
bandwidth is nearly all of 1.8 to 1.9  Both are far too broad, indicating
considerable RF loss yet to be pin-pointed and remedied.

I have a full size inverted L over an FCP, whose feed R at the shack side
of the isolation transformer is 30 to 32 ohms. This conveniently allows me
to use a Balun Designs 16132 Unun (32 ohms in, 50 ohms out) to match the
natural R of the antenna to the 50 ohm feedline to the shack.

At the Unun output, my 1.5:1 points are 1807 and 1832 for a 1.5:1 SWR
bandwidth of 25 kHz.

On the shack side of 82 feet of LDF4-50A 1/2 inch hardline, the 1.5:1
points are 1804 and 1832 for a 1.5:1 SWR bandwidth of 28 kHz at the
operating position.

Over the last two years, this antenna has been carefully designed/worked
over to eliminate loss. Removing the loss will narrow SWR bandwidth.  My
shack SWR at 1880  is 4.8:1.  Switching in secondary matching (ATR30) is
necessary to work in the high 1.8's and above 1.9.

I would be interested in the RigExpert raw feed numbers without the choke
(I have a hard-to-shake dim view of RG58, especially old RG58). It would
also be helpful to have the RigExpert model number, and measurements taken
at 10 kHz points.

Good luck on the project. You have to keep working the problem.

73, Guy K2AV


On Fri, Jan 18, 2019 at 8:23 PM Todd Goins  wrote:

> Hello,
>
> I borrowed a RigExpert analyzer and was able to take measurements that
> folks were asking for without AM station overload. I also built the K9YC
> 160m choke (18 turns of RG58 on a type 31 2.4" toroid). That choke is at
> the feed point of the vertical. The analyzer was connected directly after
> the choke.
>
> I have a collection of data and typed it into Excel but I can summarize
> here.
>
> The values are Freq, SWR, R, X, Z
>
> 1810  2.1
> 1820  1.9  29.1  -14.3  32.4
> 1840  1.8  31.0  -5.7   31.5
> 1850  1.7  32.0  -1.3   32.1
> 1860  1.5  33.0  3.6   33.2
> 1880  1.6  35.3  13.0  37.6
> 1900  1.8  38.0  22.9  44.4
> 1920  2.1
> 1940  2.5
> 1960  3.0
> 1990  3.9
>
>  I still only have the 30 x 42' radials attached but can add about 5 x 100'
> more radials (in a non uniform layout) if that might help.
>
> Fair, bad, really bad, horrible, hopeless?  Any advice is appreciated.
>
> 73,
> Todd - NR7RR
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
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Re: Topband: 160 conditions

[Guy Olinger K2AV]

They were all worn out from the NAQP, which included a mob and a lot
of good results on 160. :>))

73, Guy K2AV

On Sun, Jan 13, 2019 at 5:26 AM Tom Boucher  wrote:
>
> Outstanding sunrise conditions at 0800 today on top band. FM5BH on 1818 KHz
> S9+. ZL3IX on 1826.5 long path peaking S8/9 on my meter.
>
> RBN skimmers showing excellent path to USA but very little other activity.
> Come on guys, turn that computer off and plug the key in!
>
> 73,
> Tom G3OLB
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Re: Topband: 30 Ja's worked today on 160

[Guy Olinger K2AV]

"Nobody on CW" is probably answered better by few people listening and
most not having implemented an automated way to pick up on CW CQ's.
That's sort of built into the usual ham shack blend of FT8 and logging
programs.

In the contests, anyway, even RTTY tests and the recent RTTY roundup
with FT8 admitted to the fray, I see no diminution of participation,
the contests seem to be slowly growing.

The CWOPS weekly hour-long CW contests keep growing, with member ID
numbers well into the 2K range. It seems to have sharply caught on in
the last few years.

73, Guy K2AV

On Sat, Jan 12, 2019 at 9:32 AM  wrote:
>
> It's no wonder when I get on mornings with good conditions there are few, if
> any, JA friends to work on CW.
>
> 73. . .Dave, W0FLS
>
> -Original Message-
> From: Herbert Schoenbohm
> Sent: Saturday, January 12, 2019 6:49 AM
> To: TopBand List
> Subject: Topband: 30 Ja's worked today on 160
>
> Using FT-8 with a split 1840/1908 I was able to work over 30 JA's via a
> skewed SW path today.
>
> Amazing conditions and less polar absorption this direction.
>
> Herb, KV4FZ
> _
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Re: Topband: Inverted L improvement question

[Guy Olinger K2AV]

Given caveats stated below, the short answer is I'd bet with odds it
wouldn't make much difference.

Long answer:

One of the benefits of an end-fed half-wave L on 80 meters is the hi Z
feed, tolerating ghastly ground systems, and having all the current up high
at the bend. Arguably, this makes the 80EFHWL the best single wire 80m
antenna for a mix of DX and local (therefore also contesting) operation.
The huge drawback for most is the need for an out-in-in-the-weather tuning
device as you cannot feed it directly with a run of coax. It also is fairly
narrow band, except for CW only operators. Those who need the entire band
need to so something not-simple at the ground feed to cover a significant
range of the 75-80m band.

The half square is two of those end to end, coming together in the middle
of the 1/2 wave horizontal. On 160 that's 539 feet of wire up in the air.
If you got the space and support for that and you want that broadside
direction, that's going to be a killer antenna.

Many of the half-square illustrations show a low Z feed at one of the upper
corners. That would avoid some of the issues at ground with high Z feed.
BUT the feedline would need to be broken up at the feed and halfway going
down, and at the bottom with VERY robust common mode current blocks. See
some of K9YC's new RG400 on #31 ferrite choke designs with 15K+ ohms of
blocking for something that would actually do the job with very minimal
power loss.

The other answer, as you have implemented to to deal with the high
impedance feed at one of the ends. This requires that at the end the
antenna looks like an electrical full wave wire.

Equal coils at the corners have sometimes allowed smaller physical
dimensions. But as soon as you start modifying the antenna, then questions
emerge which need modeling to answer. So there is no certain
one-size-fits-all answer to your question without model analysis of the
not-quite-half-square you have in the air. Versions with modified
dimensions have to be carefully designed to avoid dropping back into ground
involvement and possible related losses.

Given your 2000 ohm end to ground feed Z of the "modified" version you have
up, you have PROBABLY managed to avoid issues that would kill its ground
independence.

To answer the question far more completely, model it along with any
antennas and conductors within a 500 foot radius, INCLUDING TOWERS AND
FEEDLINES.

The half square is a great idea that can be screwed up with less than full
implementation, or like many other excellent designs, can be totally
screwed to the wall by unconsidered nearby conductors.

73, Guy K2AV.

On Tue, Jan 8, 2019 at 3:45 PM Dick Bingham  wrote:

> Hello Guy (and the group)
>
> I just finished reading your reply/observations on 160-Meter verticals -
> L's, etc - and wonder what your thoughts may be for the so-called
> "Half-Square" antenna (H-S) where the high current point is at the top of
> the array and the antenna is high-voltage-fed at the bottom.
>
> I have a terrible QTH situation where ground conditions are very poor -
> basically river deposited gravel
> and sand sub-soaked by glacier and snow-melt water covered by several feet
> of organic matter. It is an electrically quiet area - S-0 or so - with
> noise basically all propagated non-man made noise.
>
> The H-S antenna I use (actually a sloping H-S with top phasing wire at
> ~90-feet) has 5ea 136-foot radials and performs very well in contests using
> 100-watts or less.
>
> My question is, given the low current at-ground feed point with Zo ~
> 2000-ohms or so, what sort of improvement might one expect if the radial
> field was significantly improved?
>
> 73 to all -  Dick/w7wkr at CN98pi
> =========
> Message: 1
> Date: Mon, 7 Jan 2019 12:07:16 -0500
> From: Guy Olinger K2AV 
> To: Todd Goins 
> Cc: TopBand List 
> Subject: Re: Topband: Inverted L improvement question
> Message-ID:
>
> Content-Type: text/plain; charset="UTF-8"
>
> Apologies to all for delay in response.
>
> Losses related to ground and close dielectric materials remain the
> single monster gorilla in the room for improving TX performance of
> vertical antennas
> BIG SNIP
>
>
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Re: Topband: Inverted L improvement question

[Guy Olinger K2AV]

 those results. (I'm including
rudimentary EZNEC instructions in case others want to do this. I doubt
you need them.)

1) In your model, open the "Loads" window. Add a load to each radial
in the second segment out from the center point. If the upper left
corner of the "Loads" window does not show "Loads (RLC)", then in the
"Other" drop down menu click "Change Load Type" and then click "RLC"
and then "OK".

2) Start with "Short" in all the RLC boxes. If they are anything else,
enter 0 as a value and hit return. Set all the "Config" and "Ext Conn"
to "Ser"

3) Do an "FF Plot" with a 3D "Plot Type" to get the 3D "Average Gain",
displayed beneath the selection grid on the main control window. Mark
that value down as the theoretical minimal loss.

4) On the main window, "Options" menu > "Power Level", adjust the
power level so that in "Load Dat" the "Current =" value is the same as
the largest of your actual measured currents.

5) Using the "Load Dat" button to pump the calculation engine, adjust
each load's R value up in resistance just enough to get the current
values you are measuring on the actual radials. This may cause the
current value of max value radial load to vary. Readjust the "Power
Level" setting to return the max radial current value to measured.

6) When you get the "Load Dat" currents to match measured values all
around, then rerun 3) and mark down "Average Gain" as theoretical
problem average gain.

7) Subtract the value from 3) from the value from 6) and mark it down
as theoretical additional loss in dB from the unbalanced radials.

8) Change "Power Level" to 1500 watts. Click "Load Data" and then add
up the eight "Power =" values. That value would be the theoretical QRO
operating losses in watts implied by the scalar current ratio's you
were getting. I suspect that is a large loss. But do the exercise.

Please pass along the results. Also if you create a whole property
model, please send the dot EZ or dot NEC to me as an attachment.

73, Guy K2AV.




On Mon, Jan 7, 2019 at 3:28 PM Grant Saviers  wrote:
>
> Guy,
>
> I need some more db's on Tx.  For Rx I hear much better than heard into
> EU from Seattle area. It's a hard path and easy to believe EU QRN/QRM is
> the main culprit.  Your "loss list" is a great list, but I am thinking
> about a different potential problem with my T with eight 125' long
> elevated 10' radials, pretty much even in directions around the compass.
>   It has a good choke and buried feedline.
>
> I have 3:1 measured current unbalance with an MFJ RF current meter I
> calibrated.  Perhaps unavoidable given the forest, lawn, towers, and
> buildings near where the radials run.  Plugging those values into Eznec
> 4.2 as a source for each radial yields insignificant pattern distortion.
>   Kirchoff's law is ok on the actual values, sum of measured radial
> currents = vertical (85' to top of T, 33' each side top loading).
>
> N6LF with his modeling shows that radials longer than 1/4wl can cause
> significant losses.  Now it occurs to me that the MFJ gave me scalar
> current values and those are not necessarily the actual i+jx radial
> currents.  I think Kirchoff is happy as long as the eight radial plus
> vertical i+jx radial values all add to j0 which was true at resonant
> frequency where I was measuring the currents.  So perhaps some of my
> radials are longer than 1/4wl RF and increasing the losses.
>
> So my questions for the wizards of top band verticals are:
>
> 1. Am I correct with my non scalar interpretation of Kirchoff's law for
> radials?
> 2. What are easy ways to measure current phase for each radial? (I have
> a dual channel scope and was thinking of making current probes of some
> sort).
> 3. Was my 4.2 pattern/gain analysis correct for the modeling of the
> unbalanced scalar currents?
> 4. Since the summed measured RF currents were correct, am I overthinking
> this about potential losses?
> 5. Do other Topbanders have experience with measuring radial current phase?
> 6. Most of the literature gives strong admonitions to "equalize" radial
> current "within a few percent" (ON4UN and others).  Yet no analysis is
> given for why or how to do that.  My modeling seems to disagree.  My
> calculation of extra skin depth loss due to higher vs equal currents is
> only a few watts.
>
> W8JI advises to think about antennas as systems that include everything,
> and the more I learn the more the complexity of the system unfolds.
>
> Grant KZ1W
> A db here and a db there and pretty soon its 3db or more.
>
>
> On 1/7/2019 9:07 AM, Guy Olinger K2AV w

Re: Topband: Inverted L improvement question

[Guy Olinger K2AV]

Apologies to all for delay in response.

Losses related to ground and close dielectric materials remain the
single monster gorilla in the room for improving TX performance of
vertical antennas.

Setting aside content on k2av.com relating to the FCP, the other
issues in that web page’s "Loss List" section apply to any inverted L,
e.g. not having a tree inside the bend, avoiding proximity to
dielectric materials, quality of whatever counterpoise, etc

Simply having the RF current maximum on a vertical wire at the ground,
largely diminished at the top, is a loss issue, unless the in/on
ground radial system is EXCELLENT.

If you are considering beefing up your radial system in stages, then
by definition your radial system is NOT EXCELLENT. You already know
the deficiencies, those are what you haven't done yet and plan to do,
sometime.

The net effect of a collection of radial system deficiencies
separating you from EXCELLENT will be at minimum over Midwest USA
magic super dirt. Ground losses move in the direction of catastrophic
as ground quality deteriorates from super to average, to poor, very
poor, junk, awful, to unbelievably bad. The vast majority of the
country has ground quality that will make you pay if your radial
system is NOT EXCELLENT.

If you have that magic, super 30 millisiemens dirt, you can do
anything and get away with it. Please do not tell us, just keep it to
yourself. We already have enough things to make us jealous or feel
bad. Enjoy all your good results with schemes that blow up in ordinary
places. I have no problem with your good fortune, I just don't want to
be reminded over and over how poor NC dirt is for RF.

But please do not offer shortcut low-band advice, because you have no
idea what awful results your scheme might get in 2 millisiemens North
Carolina dirt, or even worse in the barely covered-over rubble that
sometimes passes for dirt in urban and some suburban building lots, or
in historic areas that have been built over previous ruins for
thirteen centuries, places where the skeletons of ancient kings have
been discovered buried in medieval church ruins found under
current-day parking lots.

The enemy of a vertical radiator is loss. Specifically, 1) dielectric
loss, RF exciting increased electron energy levels without electron
movement between atoms  and 2) resistive loss, RF inducing current in
conductive but resistive materials. Dirt usually has both. Further and
worse, UNLESS there is net field cancellation at the radial wire or
below (outcome of an EXCELLENT radial system), dielectric material
within a few millimeters of radial field conductors INCREASES
dielectric loss.

RF fields at the feedpoint are huge, especially where a self-resonant
vertical radiator meets in/on ground radials. Radial deficiencies will
be costly close to vertical wire meeting counterpoise, further
multiplied by the "poorness factor" of the dirt underneath. That is
one of the gains of an elevated counterpoise, getting high fields away
from the damnable dirt where an EXCELLENT on/in ground counterpoise
just ain't possible.

Another way to reduce the fields at the ground is to quit using the
length of the vertical aerial wire as a cheap way to provide tuning
for matching to coax. If (on 160) you use an 88' foot wire as a start
for the L's horizontal, you will move the current max to 1/16 wave
down from the bend in the L. You will have done two good things, 1)
reduced the feedpoint current, hence also the RF field at the base,
reducing the power loss by the square of the field reduction, 2) put a
fairly uniform current on the *entire* vertical wire, further reducing
takeoff losses in trees, buildings, etc, by having a much larger
percentage of the total takeoff energy high enough get to sky without
encountering ANY dielectric losses.

How long to make the vertical wire? As long as you can while still
sufficiently avoiding dielectric and conductive materials. Losses from
higher current on a shorter vertical wire are outweighed significantly
by gains moving the feedpoint up in the air away from dreadful ground
losses only otherwise mitigated by EXCELLENT ground radial systems.

There are also questions about the efficiency of ground radials on top
of typical root content of "woodsy" locations. Roots are high loss
dielectric materials. Controversial, but an EXCELLENT *elevated*
radial system in the woods is going to outperform radials on ground.
Buried radials in the woods outright dismissed by many as impractical
at best.

The usual killer reason for abandoning or not adopting non-resonant
improvements to move current maximum well up on the vertical wire?
Desiring low SWR without tuning apparatus at the base of the vertical
wire. From the "Taming the exasperating Inverted L" section on
k2av.com:

**An Efficient Self-resonant Inverted L
is NOT a natural 50 ohm antenna**

Not even close. Think 20 to 35 ohms.
Varies with dimensions and environment.

**Lower SWR does NOT
predict improved performance**

A 

Re: Topband: Inverted L improvement question - Part 2

[Guy Olinger K2AV]

Hi Chet,

Before we start, a disclaimer: I still have my MP, maybe I'm a radio
hoarder. I do have a 75A3 and a Johnson Ranger and Courier and an FT 101ZD.
The only long used radios I don't still have are my SB300 and SB400, and I
wish I hadn't sold those. So my MP bashing is technical and proven, and I
still love my MP enough to keep it. I hope its feelings aren't hurt by lack
of use since the K3.

Back in the heyday of FT1000MP, when that was one of the best contest
radios available (IF you fixed the clicks), I used to take mine out to N4AF
for the multi-op DX wars as NY4A. I used my MP on 40 meters out there,
which at that time was listening to a 5 element quad stretched out on 190
feet of catenary between towers, end-on to 45 degrees. Loads of incoming RF
off the big quad.

With the MP, the bottom layer of signals was usually all the DL/OK basement
noodle antenna QRP signals. When the K3 showed up, the DL/OK basement
noodle QRP crowd became essentially workable and the new bottom layer of
signals was all the European Russians running 100 watts to a dipole up 20
feet on the southeast side of a big hill.  Goaded by the astonishing
improvement, some K3 to MP comparisons showed very convincingly that what
we always thought was the bottom atmospheric level in the MP was actually
being generated IN the MP, because it was absent in the K3. A/B there, not
there, couldn't possibly be that much. Repeat test 50 times at least,
there, not there. After a half hour of doing the same test over and over,
with exact same result over and over, "Gee, guess the K3 has improved a
lot."

N4AF switched to K3's, and very quickly all the "drug-in-with" radios were
K3's, except for one Orion I. Within a couple years, 11 FT1000MP's in the
NY4A crowd morphed into 14 K3's.

There definitely WERE some separate sensitivity issues in the MP, a bunch
caused by too much RF coming in the line in RX mode. Your deaf as a
door-nail kind of spot reports screams as a repeat of one of those MP
insensitivities.

There is a little itty-bitty choke in the RX on TX antenna circuit, which
can burn but NOT GO OPEN. It goes resistive because what's left over after
the wire burn is still conductive. The DEGREE of resistive is unpredictable
and can change. I know because over the years I've replaced a half dozen of
them. You can find them in the schematic. The quick no-solder,
no-disassembly fix to get around the problem and listen on the TX antenna
with full sensitivity is 1) on the back panel patch the RX OUT RCA jack
(connected to TX ant when not transmitting) to RX IN RCA jack right next to
it, and 2) on the front panel use ANT RX. The coil is not in the RX ANT
circuit. If you suddenly hear better, you know what to do. If you never do
SO2R or operate the MP at a multi transmitter site, you maybe don't need
the choke. The K3 has a COR relay for this.

We always replaced the @%#@^&!! chokes because we were afraid to run the
MPs at the multi site without those as protection for some cross-antenna
backfeed we had unknowingly reintroduced.

I can't explain the MP engineering there. That's just how it is.

If you bought the MP second-hand and in its other life it was operated at
high power multi sites, it could have been that way since you had it,
therefore no suddenly worse performance as a clue to check things out.

Anyway, I would check that out before you go tearing up all your antennas.

73 & HNY all,

Guy K2AV

On Sun, Dec 30, 2018 at 8:35 PM chet moore  wrote:

> Todd,
>
> Thanks for sharing. I've been following your post.  I too wondered about
> sharing the radial field like you did.  My situation is somewhat similar in
> that I feed a 90 foot tower which has a c31 at 95  feet and a two el xm 240
> 40m beam  at 75 feet beneath it on a gatethe antennas should give me
> some top loading but it has never been modeled.  Shunt wire presently comes
> down from 70 feet about 3 feet out from the tower to the base of my tower.
> The Tower(AB-105) Is guyed at 40 and 70 feet, guys are broken up with
> insulators. I have tried to find the resonant  freq of the tower  and at
> one
> time or another I have moved that tap from 40 feet to up 50  60 70 feet in
> 2
> foot increments. (that's a lot of climbing)and  never found the sweet spot
> if there is one. I saw your post and  Like you I  wondered what  would
> Happen if I  ran an inverted L up to 90 feet. (I already had a pulley and
> rope up there) and run the tail out to the west since I seem to be "deaf"
> to
> the west and north west (and really everywhere) and would share The same
> radial field which  has 2 radials that I was able to stretch out to 100
> feet
> (in a very crooked line)  and a couple of others  that are 60 feet  and 56
> others  of various lengths from 20 to 50 feet. The correct word is probably
> not "share" as only one of the antennas would be hooked to the xmtr at a
> time.  My salt water swimming pool Is about 8 feet from the base of the
> tower. Not sure if the pool helps or 

Re: Topband: Rather use N-type (was Re: The answer to PL-259 soldering/reliability problems)

[Guy Olinger K2AV]

I agree with Rick,

If an N connector is not designed to fix the relationship of the center pin
(soldered to the center conductor) to the body it should not be used
outdoors or on long runs of unburied coax exposed to full seasonal
temperatures.

I learned that the hard way on unfixed pin N connectors terminating 230
foot runs of LDF4-50A at my tower. Of course it happened on the 40 meter
line on a particularly cold Saturday night in the CW SS . Had to
repair/resolder on the tower by flashlight in 25 degree weather. The next
summer after removing the up-tower flexible coax it wouldn’t reconnect
completely. The pin was now out too far.

These days I am terminating my LDF4-50A with Andrew L44P UHF male
connectors, or dressing the cable and soldering it directly into the
terminating circuit.

The male pin in a UHF connector has enough overlap with the female receptor
that a certain amount of temperature induced movement will no longer break
the connection.

73, Guy K2AV

On Thu, Dec 6, 2018 at 10:48 PM Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> I used to have many coax cables with factory installed type N
> connectors.  Virtually all of them have sooner or later
> suffered from the center conductor pins either retracting or
> extending outward over time.  Once the pin moves far enough
> either in or out, the connector will no longer mate.  I have
> been able to temporarily rehabilitate some cables with the
> retraction failure by pulling on the center pin with vise
> grips.  If they overextend, there is no way AFAIK to fix
> them besides replacing the connectors. Evidentally,
> none of these cables used connectors with a captivated
> center conductor.  I have seen this in coiled up coax,
> coax hanging from a tower, and coax just laying on
> the ground.  Coax used/stored only indoors seems to be
> immune from this problem.
>
> I would be interested in hearing from other people who have
> observed this problem.  Am I somehow doing something wrong
> to cause this?
>
> Rick N6RK
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Re: Topband: new style PL-259's with screw on back INSTRUCTIONS

[Guy Olinger K2AV]

Hi Terry.

Whatever you are referring to didn’t make it through the reflector. Can you
provide us with a URL link to the connectors?

Thanks and 73, Guy K2AV

On Tue, Dec 4, 2018 at 9:46 PM terry burge  wrote:

> Hello guys and gals,
>
>
> I just bought 10 of these from China. Free shipping if you don't mind
> waiting a couple of weeks. Anyway I'm not exactly the best soldering guy on
> the block and would like to know if there is some webpage that shows how to
> install these new style coax connectors. They sort of look like RG-6 style
> with the strange tube for separating he center lead from the coax. The ones
> I did not use vs. the screw down ones (old style I think). But of course
> these are larger for RG-8, LMR-400, RG-213, etc. I'm thinking they will
> probably be more reliable. Hoping anyway. So can anyone help with this?
>
>
> Don't even know if they have a 'different' designation that PL-259's.
>
>
> Terry
>
> KI7M
>
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Re: Topband: N4KG reverse-fed vs. Gamma/omega

[Guy Olinger K2AV]

Hi Kenny,

You set your curiosity on a real toughie. Tread where angels fear to go,
and all that.

The N4KG feed is extremely situational in its efficiency, or some
efficiency, or no efficiency.

It can be modeled in NEC 4, the version of NEC which allows you to have
conductors both above and in the ground. You need to explicitly model the
base of the tower down into the ground to see all that is going on,
including driving RF power into resistive ground, which is why you need to
model it. The model must also contain explicit description of the tower and
all the aluminum up the tower.

Then it becomes easy to see what is going on. And why it works over here,
and can be a dreadful failure over there.

At the point where the coax shield is attached to the tower, the current
will attempt to go both ways. The current off the braid will be divided
between going up the tower and going down the tower by Ohms law for
impedances at the operating frequency. The up and the down paths are not in
series, they are in parallel. And  The down current will be driven into the
ground which appears as this big ugly lossy resistor.

If the path up the tower, a combination of wires on the tower, yagis yada
yada looks like a 150 ohm part R part X very miscellaneous impedance, AND
the path down the tower into the ground looks like thirty-something ohms
resistive, most of the RF current goes into the ground, wasted. Noting that
the division of power between the two is proportional to the square of the
division of current, in that case less than 10 percent of the power goes up
the tower and the thing performs like a dummy load. Even if you do some
stuff to compensate, every time something is done on the tower, you risk
undoing the compensation.

You might try to fix that nasty tower-base-to-dirt resistor by putting down
a good radial field, to reduce the resistance of the down path to 1 or 2
ohms.  But then you've just done the hard part of setting up a stoutly
performing loaded tower, and the gamma/omega match actually can be adjusted
to present a 50 ohm load to the coax. The whole idea of the N4KG scheme was
after all, not to have to do ground radials.

All in all, this is why you see and hear of many gamma and omega-matched
towers that perform well, AND 24 years after the N4KG article you have to
ask around, and discover only scattered instances of one working well,

There is a way to accomplish what was intended by the N4KG method, if you
can't actually produce the tower plus antennas above the feed that actually
IS an electrical quarter wave:

1) use an inverted L with the bend supported by the tower as the directly
powered radiator. This takes the natural wide variation and uncertain
behavior of tower top stuff out of play.

2) use an FCP for your counterpoise. Plus and minus 33 feet on 160. This
gets you out of the need to find a 125 foot radius for (in the KG case) for
four resonant 1/4 wave elevated radials.

3) have an isolation transformer to a) insure that the initial direct
driving power only goes to the L/FCP and nothing else, b) the L/FCP is
completely isolated from any conductors except the supported tower [see 4)].

4) now, since the L will induce the fool out of the tower which is just a
few feet away and parallel to the L's vertical wire, counter the induced
voltage in the tower with an intentionally placed horizontal shorting wire
from the vertical wire to the tower.

5) even if you can only reduce the current in the tower to 1/3 of that in
the L/FCP, by the square law, that means more than 90 percent of the
radiation is from the L  and less than 10 percent of the power is subject
to reduction by being driven into the ground at the tower base.

This scheme is explained on k2av.com, in the section "65+ Tower L Bend",
and illustrates what goes on with the RF current down at the base of the
tower, which is the same issue with the N4KG feed. Even if you could care
less about an L/FCP, the issue at the bottom of the tower is the same for
both, and the documentation for a floating L/FCP supported by a tower will
explain the issue and why you can't ignore it. .

Doncha love this stuff?

73, Guy K2AV

On Mon, Dec 3, 2018 at 1:02 PM Kenny Silverman  wrote:

> I meant to ask if the antenna efficiency (dB) was better with either feed
> method.
>
> Regards , Kenny K2KW
>
> > On Dec 3, 2018, at 10:15 AM, Kenny Silverman 
> wrote:
> >
> > Has any analysis even done comparing the N4KG reverse-fed tower feed
> method with elevated radials vs a shunt or omega feed with ground radials?
> >
> > This is a tall tower and I think it will be close to self resonance  or
> longer.
> >
> > Regards , Kenny K2KW
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Vertical antennas aren't always best for DX everywhere - the facts

[Guy Olinger K2AV]

Have to remember that W8JI, ON4UN and many others were not lying or
deceived. What we are finding out is that a major rule has some exceptions.
If you're talking to a club member in the US, you better point them to
verticals, T's or inverted L's.

One of the missing aspects of dipole vs. vertical comparisons is the major
risk of a poor lossy counterpoise for the vertical. People have lost quite
a bit more than 1/2 their power in bad radial implementations, or in
various loss issues not affecting a dipole.

One of the contributions of an inverted L is filling out the high "hole" in
a vertical ot "T" radiation pattern. That could account for a lot of
differences. Knowing absolutely the incoming angle on DX is still something
without a lot of measured documentation around.

Never can have enough antennas.

73, and may you work whatever you hear,

Guy K2AV



On Mon, Nov 26, 2018 at 4:20 PM Mike Waters  wrote:

> This has been an eye-opening discussion for me! I have always preached the
> 'gospel' of vertical-is-usually-best based on W8JI, ON4UN, and *many* other
> long-time Topbanders. Someday I'll have to revise
> www.w0btu.com/160_meters.html and include a link to this thread.
>
> I stand corrected. Thank you, gentlemen! :-)
>
> 73, Mike
> www.w0btu.com
>
> On Mon, Nov 26, 2018, 12:56 AM Steve Ireland  wrote:
>
> > Hi Frank (and Rick)
> >
> > Somewhere I have a map of the lines of geomagnetic latitude superimposed
> > on a Mercator projection of the world, but I can’t find it right now.
> > Unlike the ruler-straight lines of conventional latitude, geomagnetic
> > latitude lines wander across the world like a collection of snake tracks.
> >
> > As a result of how geomagnetic latitude snakes across the globe, a
> > comparison can’t be directly made between similar geomagnetic latitudes
> in
> > the northern and southern hemispheres – where Tom W8JI lives is probably
> > very different to me in terms of the closeness of his geomagnetic
> latitude
> > to the electron gyro-frequency.  As Carl K9LA points out, the geomagnetic
> > latitude relates to polarization and involves the ordinary and
> > extraordinary waves that propagate through the ionosphere, and how 160m
> is
> > affected by being close to the electron gyro-frequency.
> >
> > About 10 to 15 years ago, Carl, Nick Hall-Patch VE7DXR and Bob NM7M (SK)
> > (also a physicist like Carl, as I’m sure you recall) helped Mike VK6HD
> (SK)
> > and I to understand why our horizontal cloud-warmers outperformed
> efficient
> > vertical antenna systems in SW WA.
> >
> > You are quite correct, the Fresnel zone where I live (the mostly far
> field
> > region where ground gain is developed) has very poor conductivity. And,
> to
> > repeat your point as this is not as widely known as it should be, poor
> > Fresnel Zone conductivity has very little impact on the performance of
> > horizontally polarized antennas, while having a major impact on
> vertically
> > polarised ones.
> >
> > While the Fresnel (far field) zone of my location, is basically rock
> > (granite and ‘coffee rock’), Mike’s final location beside the Kalgan
> > estuary appeared to have much better Fresnel zone conductivity, with less
> > rock than me and, in around half the compass directions, salt water.
> > However, his inverted-L with an 80’ vertical section over 120 buried
> > quarter-wave radials at Kalgan performed only marginally better than our
> > previous attempts at vertical antenna systems did.
> >
> > On this basis, I came to the conclusion that the dominant problem was
> > likely to be the geomagnetic latitude issue, rather than poor
> conductivity
> > in the Fresnel zone – which it certainly is also an issue here.
> >
> > To investigate this further, I sought out the opportunity to operate
> > directly by the sea here with a good vertical antenna. After much
> > paperwork, I managed to get permission to operation from the Cape Leeuwin
> > lighthouse, which is 40m-plus high and on a narrow finger of land
> > surrounded by sea for over 300 degrees.
> >
> > In a Stew Perry TBDC in the early 2000s, with the assistance of my friend
> > Phil VK6PH, we put up a full-sized quarter-wave wire vertical on the most
> > seaward side of the lighthouse, less than 60 metres from the sea. This
> was
> > fed against a quarter wave counterpoise and the feeder decoupled with a
> > large ferrite choke to stop common mode effects.  On the other side of
> the
> > lighthouse was an inverted vee half-wave dipole. Both antennas were
> > supported from the lighthouse balcony (at about 40m!) and detuned when
> not
> > in use. An Yaesu FT-1000MP was used, running less than 100W
> >
> > Unfortunately conditions were poor during our evening time into North
> > America, but at about three hours before sunrise the 160m band opened
> into
> > Europe.  Right from this point, the vertical was slightly down on the
> > inverted vee by a few dB, but I would always call on the vertical first
> and
> > then switch onto the 

Re: Topband: 160m Antenna, worse than I thought !

[Guy Olinger K2AV]

Hi Mike,

You certainly are not the first to experience an antenna "grounding" that
makes unbelievable the contacts actually made with it. BTDT for sure

Another thing is our common predilection for thinking that SWR means
anything other than when it has a large change, something has happened. But
surely SWR does not show every large change in antenna condition nor does
SWR predict performance. We should really get over that procedural urban
myth.

Just remember that a dummy load has a perfect SWR and, at 99.9% power loss
to heat, is a worse antenna than a light bulb.

73, and may we all somehow remember all our hard-earned lessons,

73, Guy K2AV

On Mon, Nov 26, 2018 at 3:27 PM Mike Smith VE9AA  wrote:

> de Mike VE9AA
>
>
>
> O-M-G -,If you read my 3830 report from CQWW CW.. I thought my 160m antenna
> had just 'fallen down' and was still 130' or whatever feet of wire at
> ~12'AGL, but when I was out in the woods just now, nice bright sunny day
> that it is (0*C/32*F), I *REALLY* saw what was going on.  I couldn't
> believe
> my eyes.
>
>
>
> After my 24hrs (Classic) was up post-test I went outside y'day in the late
> afternoon and instead of hiking through the snow, I used binoculars and
> looked across the field and down into the woods and 'thought' I knew what
> was up.
>
>
>
> It was only in the light of the noonday sun today, after I had hiked
> through
> the snow that I saw it..OMG, I laughed so loud.   I am not sure how I made
> *ANY* QSO's at all. (even one DX QSO into the Carib!)
>
>
>
> My inverted L antenna had broken about halfway or more.  It went up from
> about the 6' level, (where the base of the inverted L is) to about the 12'
> level, then.wait for it...it came directly down to the ground and was
> all bunched up in a heap mostly covered in about a foot of snow!  What I
> saw
> yesterday, was apparently a raised radial from one of the 80m 4-square
> verticals .  Essentially, I was transmitting on an inverted-U antenna 6'
> up,
> then 12' back down, with a big blob of 70-80' of wire at the far end,
> laying
> on the ground in a heap, mostly buried in snow. a huge rats nest.  I see
> another bit of antenna way up in the trees over yonder which I think is the
> end of this one.
>
>
>
> So, the moral of the story is check your antennas WELL, (in person, before
> the contest) and don't assume, and don't be so lazy as to use binoculars
> when you have lots of wires zig-zagging this way and that.  With all the
> snow on top of it, I bet it's been this way for well over a week, maybe two
> and I could've probably fixed it before the contest.  I hear 160m condx
> were
> stunning and I really missed out, especially with no 10m prop and 2 broken
> antennas for 15m.  SIGH.
>
>
>
> Strange thing is, the SWR wasn't that bad.  About 2.1:1 with a nice dip @
> 1830kHz...bizarre...when VY2ZM was only 559 here, that should've been my
> clue that something was seriously wrong.
>
>
>
> What a goof I am.
>
>
>
> Learn from my mistake.  Don't assume SWR means everything is all OK.
>
>
>
> LOL! / HI HI
>
>
>
> OK, back into my igloo I go.
>
>
>
> MikeAA
>
>
>
> Mike, Coreen & Corey
>
> Keswick Ridge, NB
>
>
>
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: FCP for lower power

[Guy Olinger K2AV]

Hi, David,

Regarding the FCP 160-80 meter dual banding project and circuit component
sizing particulars ... I completely understand the urge to downsize.
However, the devil is in the blasted details.

This question faithfully recurs from time to time: Can we use smaller wire,
use a smaller core, smaller relays, etc? That is why I have replied to the
list instead of off-list. You have some company in your inquiry, and likely
will have more. I'll also likely turn this into an FAQ entry.

The question originates in the understandable but incorrect idea that the
only or essential reason for our using larger components is to prevent
burning them up while running QRO.

Back in pre-publish days Jack and I were locally famous for burning stuff
up and setting utility buildings on fire. And we DID work to have our
creations not catch on fire. But ultimately we realized that sneaky
accumulated miscellaneous losses were more sinister than fire risks. With a
main and ultimate goal of helping people to get out and make QSO's, we had
to refocus our thinking on eliminating loss to continue with new discovery
and progress.

In the FCP, and related projects in the loss list, the central design aim
is to REDUCE LOSSES.  Avoiding burning up at QRO power levels IS one, but
ONLY ONE benefit from using larger components. And it is NOT the essential
or controlling issue. Nearly all of the sizing decisions on k2av.com have
to do with reducing dB loss, considerably more critical to results at QRP
than it is at QRO.

Loss reduces performance, and loss will affect QSO's far more often at QRP
power levels. QRP operators are most likely to be in the noise at the
distant end, even when QRO's extra 25 dB puts that QRO signal well out in
the clear and armchair copy. When one's TX signal is in the noise at the
far end on difficult propagation paths, all those recovered tenths of dB's
and possibly a few entire dB's added together can enable copy and QSO at
the far end.

The subject of toroid core sizing can be difficult to understand and
explain, but downsizing DOES have costs. In toroids with high coverage
windings, all else held equal, eddy current loss in watts increases with
the square of the inverse of the toroid volume, thus putting smaller
toroids at a disadvantage. The smaller inside circumference of smaller
toroids may force the use of smaller wire, with less insulation and more
copper loss in the winding, to keep the same number of turns in the
winding. These are the two main problems with using the T200 powdered iron
cores for FCP isolation transformers. Again, this hurts results at QRP more
than at QRO.

Separately there are the issues of breakdown voltages and capacitor RF
current handling. We can be tricked if we don't pay attention to some
sneaky square law subtleties.

Sizing of relays in this project involves breakdown voltage, not power
dissipation. Unfortunately for expense scrimpers (count me in that group),
voltages reduce only with the SQUARE ROOT of the reduction in power.

At 1500 watts NEC4 shows the RF voltage at the FCP shorting relay to be 8
kV peak-to-peak. Adding a 50% safety margin for situations not in the model
sets the required voltage rating at 12 kV. Dropping power from 1500 to 100
watts lowers voltage approximately by a factor of 4, to 3 kV which includes
the safety margin. Dropping from USA 1500 to British 400 watts only cuts
voltage numbers in half.

On the bright side, I have seen Jennings RD5B vacuum relays, well-suited
for the FCP shorting application, go for as little as 35 USD on eBay. I
paid a surplus house 90 USD for the one I am using.

Choice of a non-vacuum capacitor for the circuit does involve breakdown
voltage. BUT far more importantly for solid capacitors, the choice requires
knowing their internal resistance and/or their current carrying capacity.
Here, as with voltage, the current reduces only with the square root of
power reduction.

Regarding vacuum vs. solid capacitors, there is a large gap between the
current handling capacity of various film type capacitors and those using
special material such as HEC-50 series transmitting capacitors. Three HEC
170 pF in parallel for a fixed 510 pF for the 80m network cap can
reasonably handle 12 amps RF circulating current in the circuit.

Other types of caps seemed physically large enough, but had no published
manufacturer's ratings for RF current. They began overheating in only three
minutes at QRO, easily seen in quickly increasing SWR following the
heat-driven change in capacitance. In minutes, the caps were too hot to
touch.  At my location at 1500 watts, only the HEC's and vacuum caps have
survived. More important, caps with runaway heat at QRO would have the same
dB LOSS at QRP, but offering no loss warning from smoke and wild SWR's when
TX.

Alas, there seems no cheap or junkbox way to construct without breakdown or
loss.

Using the Deltrol relays with increased contact spacing seems to clearly
cover voltage from only 100 or 200 watts, 

Topband: VP6D

[Guy Olinger K2AV]

Went looking for them after finishing the 0300Z CWT on 160m. He was
down the band some from where the CWT mob had been. I had seen
somewhere that they were working up 2. Called him once up about 2 and
worked him about 0410Z. Listened for a while. He was working a mix of
EU and USA.

Clearly a fine operator and seemed to be hearing very well on 160.

You can work this guy. Go get him.

By the way, during the last 15 minutes of the CWT, on 160, found
myself being QRM'd by a UW6, who wasn't hearing or calling me, who was
louder than some of the midwest USA stations, who at the time were
bedeviled by long deep QSB. I had to QSY to get away from him so I
could hear weak stations calling me.

This is going to be a very interesting 160m season.

73, Guy.
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Adding chicken wire or mesh on top of radial field

[Guy Olinger K2AV]

Quite late in response, partly done much earlier. Sometimes I have time,
and sometimes I have a house and a spouse.

Peter's original question in this thread was why a radial and mesh mix in a
counterpoise should have the radials and mesh bonded together. That is
quite a different question than why mesh at all, or how good is mesh by
itself, or mesh versus radials, or just how does "ground" behave at the
seashore.

In the 1937 Brown, Lewis and Epstein (BL) study, field strength was **
MEASURED ** at one mile at the frequency of 3.0 MHz over 15 times 0.4
wavelength radials, as well as over 113 times 0.4 wavelength radials, with
and without a 9 foot square mesh ground screen *over the radials*.  {BL:
Ground Systems, Proceedings of the IEEE, June, 1937, p. 782}

Over the 113 radials ZERO change, "with" vs. "without" ground screen,
relative field strength 1.0 (0 dB)

Over the 15 radials,

  "With" the screen:  relative field strength 0.785 (-2.1 dB)
  "Without" the screen:  relative field strength 0.555 (-5.1 dB)

   "With" was a *measured* improvement of 3.0 dB over "without", but still
significantly less than the dense 113 radial field.

Assuming that the mechanism is the mesh covering loss that would otherwise
be beneath it...isn't it interesting that over 15 ground radials 3 dB was
lost in the first 9 feet away from the center of the vertical at the
ground.

We should understand the why's of losing 2.1 dB from the dense radials and
then 3.0 dB more without the screen. Blowing an S-unit would certainly seem
significant. AND that was 15 times 0.4 wavelength evenly spaced radials,
not 15 miscellaneous length, shape and position radials.

In 1937 the only calculation device available for calculation from formulas
was the slide rule. Computers, running at GHz frequencies solving antenna
problems with quadrillions of intermediate steps in intricate and advanced
algorithmic methods, were six decades in the future. As such BL must be
given credence, as a number of very interesting graphs of RF fields and
current could not possibly have been anticipated, or "modeled" by any
process or means available. They HAD to MEASURE to have anything.

BL were being paid to go through this exercise and had a paid staff for
assistance, and funds to purchase the best test equipment of the time. They
could expend the resources to actually measure everything. They overcame
the obstacles so often defeating our modern personally-funded attempts with
the deep dollar pockets of the RCA corporation. RCA in turn had a huge
vested interest in completion of the research, building up commercial AM
broadcasting.

BL were explorers in a field mostly still unknown. They have
extraordinary graphs that put the lie to some corners of today’s thinking
where models’ approximations have been accepted as fact. We *should* have a
science of the limits of modeling and issues with “boundary situations”,
but seemingly do not.

BL DID have VERY sensitive thermocouple field strength and power
measuring devices with exceptional accuracy. When I was employed by AT
Long Lines in 1963, way back when I still had hair, variants of these were
still employed for standard maintenance practices. They were significantly
better than anything I myself have owned since. Just BULKY :>))

Sherwood describes a comparison where *only* mesh screens are used as an
*alternative* to radials. His study does *not* measure the *interaction* of
a mesh over radials in any configuration, as queried by the originator of
this thread.

Good luck, all and may your 160m wire "smoke 'em" in tomorrow's Pre Stew.

73, Guy K2AV

On Mon, Jun 4, 2018 at 3:24 PM, Grant Saviers  wrote:

> For simulating a solid conducting plate in NEC with wires, Roy Lewallen
> (EZNEC author) advises 0.1 wavelength on a side squares of wires.  That
> would be 16m for topband.  Since adding the mesh is a search for tenths
> more db's, be conservative and use half his recommendation, 8m or 25'.
>
> If a reasonable radial field of 36 wires x 125' were installed, then
> pi*D/36 = 21' tip separation (or do the trig for 10 deg angles).  However,
> buried radials don't need to be 125' long due to the effects of ground,
> thus the tips will be closer together.
>
> So IMO, based on that guidance, matting at topband wavelengths is not
> worth it, especially considering how close together wires are near the base
> of a vertical.
>
> If a research answer is required, with NEC4.2 (EZNEC Pro/4) you can bury a
> mesh in the ground, connect it to the radials, and analyze it.  NEC2 will
> give close answers with radials and the mesh an fraction of an inch above
> ground at a fraction of NEC4 cost.  It would be a real PITA to build the
> wire model for radials and a square mesh since wires have to connect at
> segment junctions.
>
> Grant KZ1W
>
>
> On 6/4/2018 0:04 AM, Raymond Benny wrote:
>
>> Peter:
>>
>> Is this a question or what you are saying is a know fact?
>>
>> I am very interested in this outcome since I will a 

Re: Topband: Inv L with FCP Tuning

[Guy Olinger K2AV]

Hi, Julio,

Sorry for delay. I didn't see this post when it hit the reflector.

Around 2009 before publishing the FCP design, the change to polyimide
coated wire and Teflon sleeve brought a string of toroid device failures to
a sudden and permanent halt and turned previously "fragile" devices into
build-it-once-keep-it-for-life items.

At root this specific choice (sleeving and coating) relates to:

1) Availability: The polyimide wire (used in automotive products) and
Teflon tubing are fairly common.

2) Hardiness: Teflon sleeving protects polyimide from nicks and abrasion in
construction and installation

3) Lightning: Since these transformers are used outdoors and near or on
lightning fodder like trees and towers, enough insulation is needed to
withstand surges from nearby lightning strikes. 55 kVDC combined insulation
between primary and secondary in isolation transformer appears to be more
than enough except in direct strikes. Nothing you can do will **guarantee**
protection from damage in a direct strike. May improve odds, but no
guarantee.

4) Static voltage: 55 kVDC is enough insulation to withstand wind static in
winter.

While not being destroyed running 1500 watts certainly is a helpful
outcome, 1) 2) 3) 4) above have a larger insulation requirement with their
higher voltages, and **apply equally to QRP, LP and QRO.**

Not breaking down at QRO gets a free ride if you have solved 1) 2) 3) 4).
Historically our principal problem with QRO power per se had to with
attempting to use ferrite and its high mu in highly reactive situations,
and in generally unsuitable antenna/feed designs with very high common mode
voltages.

If the polyimide wire is not sleeved, then easily made nicks can and
probably will break down and start carbon tracks at 100 watts. The
polyimide withstands heat and voltage well, but is fragile and easy to nick
if mishandled.

Double polyimide #14 and teflon tubing is the specific choice used by
W2FMI(SK) for cause as explained in his balun book for items with this kind
of stress. {"Understanding, Building, and Using Baluns and Ununs -- Theory
and Practical Designs for the Experimenter."  Jerry Sevick W2FMI (SK),
Copyright 2003 CQ Communications, Hicksville, NY}

You can't lay coated wire directly on cores. Cores can have tiny little
sharp places which will penetrate/nick the coating as it is being wound. Or
a drop will bang the wound wire hard on the core. Been there, done that.
This is NOT speculation. It has to be protected with something. Polyimide
coated wire, if it is never ever nicked, before or after winding, will
function until an arc to the core.

Teflon sleeving, immediately pulled over the polyimide wire before winding
and exposure to environment, is protection against nicks and ordinary
handling. This creates an isolation transformer that withstands induced
voltages from nearby lightning and so will not send those surge voltages
down the center conductor to the shack.

In the beginning W0UCE and I tried all the cheepy short cuts (which turned
out to be long-cuts), but thankfully eventually learned from our dumb
mistakes.

Verbal out-takes from the FCP development saga, we were really bad...

"Wow, I didn't know we could destroy anything that fast."
"Why is the SWR curve so flat?"
"He's asking if we are running low power (we weren't)."
"That really blew up into a lot of pieces. Make a good rattle."
"When did you buy this coax?"
"This isn't soldered and it's full of water."
"Jack, your utility building is smoking. Really, it's smoking."
"Wasn't this core supposed to be painted red? Maybe the fire changed it's
color? Uh, I think that's ferrite and the wrong size core. When did we make
this? Is this one of ours? (It was)."
"We're going to have to order it and wait. In the meantime let's try this
stuff."
"Didn't we do this same thing last year?"

73 All,
Guy K2AV

On Tue, Sep 4, 2018 at 2:59 PM VE3FH via Topband 
wrote:

> Jim,
> Did you build the isolation transformer exactly as described in K2AV's
> article?? By exactly I mean using "teflon sleeved double polyimide
> insulated" wire. I'm not planning on using it with more than 100W...
> 73,Julio VE3FH
>
> Sent from Yahoo Mail on Android over Bell Mobility Network.
>
>   On Tue, 4 Sep 2018 at 12:44, James Denneny<57jndenn...@comcast.net>
> wrote:
> Gary, I use an inv L with K2AV FCP and matching balun.  I purchased a
> RigExpert AA-30 to tune out the reactance.  It worked great.  No tuning cap
> or inductor were needed.  It took just a couple cuts to dial it in.  My L
> is now 126 ft long with a 65 ft vertical leg standing a few feet off a tree
> trunk. The SWR is now much sharper as it should be.
>
> We live on a small lakefront lot and there was not sufficient room for a
> decent TB ground radial system.  Our location is semi-rural.  So, man-made
> noise is not a frequent issue. The FCP and trimming of the antenna has
> produced a major improvement in the L’s performance.  It enabled me to
> reach TB DXCC  this past 

Re: Topband: In L in Tree

[Guy Olinger K2AV]

I sometimes get around to posting on these things only when I'm not buried
by something else. So late as this may be...

I'm sure that the writer truly meant "worked very well", but that is not a
scalar description. "Worked very well" is a degree of satisfaction, however
else someone may measure that and render it in objective scalar fashion. I
do not doubt Mike in the least that his L was quite satisfactory to him.
Whether that should be tendered as advice is another issue.

There decidedly ARE loss issues with trees, even if not adequately
described, explained and quantified to hamdom in general (they really are
not). Take as example my own day of reckoning with the issue.

A few years back, I unwisely allowed three fast-growing sweet gum trees to
grow up underneath my 160m inverted L, "inside the bend" of the L. As they
grew, the sweet gums started tangling the inverted L in storms, and I began
plotting their demise.  When a massive unhealthy loblolly pine began
drifting off vertical toward my neighbor's swimming pool, I called my tree
pro to remove it. While they were here I had them take down the three sweet
gum trees.

Being curious what difference it might make to TX signal strength, when the
tree guys were ready to take down the sweet gums, I took a 1.825 MHz RBN
reading from W4KAZ, 7 miles away. I had tree guys wait until I got the RBN
reading and *ran* out and told them to start. It took them 11 or 12 minutes
to get all three on the ground. When the last one was down, I *ran* back to
the house and redid the RBN. Running to minimize the time between
readings.

The RBN reading immediately increased 2 or 3 dB, and remained increased on
following days. The elapsed time between readings was 14 minutes, at
roughly solar noon.

The weather on the day the trees were cut down was cloudless, summery hot
and dry and we had been without rain for more than a week. During "summery
months", readings from W4KAZ in continuing summer dry weather will remain
constant (ground wave) a few hours before solar noon through 2 to 4 hours
after solar noon. From summery day to summery day, eg Monday noon and then
Tuesday noon, the before-cutting-down-trees solar noon RBN reading would
vary on average less than a dB from the previous day.  This entire improved
pattern continued after the tree felling, elevated 2 or 3 dB over
with-sweet-gum readings. The difference persisted until the next time the
inevitable branch fell across KAZ's 9AY used for his RBN SDR antenna, and
the 9AY was rebuilt from scratch.

This rather violent change after cutting down the trees (~ half my
transmitted power restored) was a considerable surprise to me and sent me
off on a quest to find out why. The answer is on k2av.com in more detail in
the section "Place an Inverted L", look for "no trees inside the bend."

This is a factor particular to an L, a much lesser extent to a T, where the
field intensity (NEC4 near field tables) is FAR higher inside the bend of
the L than on the outside, 6 to 8 times more. The loss in watts from a
given dielectric mass inside the bend will increase as the SQUARE of the
increase in the field, making those sweet gums I just cut down 36 to 64
times more loss-causing than had they been in front of the bend, more lossy
only because they were inside the bend.

So we'd best not advise someone, "just don't worry about the trees." In
different degrees of urgency, particularly if added up, the total
miscellaneous dielectric material issues at a given QTH can approach the
losses of a very poor counterpoise or radial field. See the "loss list" on
k2av.com.

The scalar objective answer is complex and situational. In certain building
lot physical circumstances, an L could be inadvisable, e.g. lots of trees
inside the bend, which cannot be removed for any one of a pile of reasons.
An L in the woods, run up next to the trunk of a tree and then thrown over
the support tree and adjacent tree canopy, depending on the insulation of
stranded antenna wire to prevent arcs to the tree, is the absolute worst of
all worlds. I know of one such case where the RBN was at least 10 dB below
what should reasonably be expected.

We have figured out a procedure for measuring loss data through the woods,
but mass data gathering has not begun. The experiment is sitting there
waiting to get done. A lot of work.

It is a good thing to avoid/clear out dielectric mass outside and
especially inside the bend of an L, retain the 88' foot top load that forms
the bend of the L. The top load increases the current up high on the
vertical wire, where radiation has to go through a lot fewer trees in the
woods getting to the sky than radiation from down low.

73 and hope to see folks on the Pre-Stew tomorrow,

Guy K2AV






On Tue, Oct 2, 2018 at 8:58 PM Mike Waters  wrote:

> Jose (et al), I respectfully and strongly disagree that this QST article
> applies to 160m to the degree described in that PDF (which does not even
> mention 160 meters!). I DO agree with 

Re: Topband: Mixed RF grounds

[Guy Olinger K2AV]

Hi Mike,

For elevated 1/4 wave radials to work well, they need to be carrying the
same RF current away from the common center point. This is to produce near
net zero RF fields at the ground. 1/8 wave elevated radials with an
isolation transformer per k2av.com will do better than the same number and
orientation of elevated 1/4 wave radials. All that the 1/4 wave radials
provide is resonance, but at a cost of increased ground loss vs. 1/8 wave.

The way to model these kinds of things in EZNEC is to do a near field table
100 meters by 100 meters square centered below the vertical wire. Set the
interval to 1 meter for 10,000 readings. Save the table to file and import
it to Excel. In Excel, square the field readings and add them up. Watt loss
in the ground will be proportional to the sum of the field value squares.
On k2av.com click the index button "The FCP Story". This is a PDF of the
original NCJ article on the FCP. At the top of page 22, there is a graphic
showing this arithmetic already done for the sum of field strength squared.
Study that before reading on here.

The additional loss for the 1/4 wave radials is simply the length, **in
feet or meters, not wavelength**. If you had to make your radials out of
nichrome wire, that extra loss would proportional to the length of the
radials in feet/meters, not wavelength. Because of the great length of a
1/4 wavelength on 160, top band is the most sensitive to these issues.

The break even point FCP vs. 1/4 length radials is *four* straight at 90
degree angles without any close local materials to make current unequal in
the radials. **IF** the radials' orientation, shape, length, etc are
"miscellaneous", the FCP will beat it. The literal difference in watts will
depend on the TX power, and particularly on the type and quality of ground
underneath. You can do ridiculously poor top band engineering over certain
highly conductive Midwest USA soils, but here in poor soil NC, or in
urban/suburban extremely poor "soils", that poor engineering will cost you
dearly in ground losses.

To compare these solutions, know what stations on the air in the same metro
area have what for antennas and run what power. In a contest, listen to
them yourself or put them up on an RBN spot analysis to various parts of
the country.

73 and hope to see all of you in the Pre-Stew tomorrow night.
Guy K2AV

On Fri, Oct 19, 2018 at 6:46 PM Mike Waters  wrote:

> Iain,
>
> The FCP is a *great* design by Guy, K2AV. It's for Topbanders on a small
> lot, but it sounds like yours is not as small as some. From what I've read
> here, whether an FCP will improve your signal over two λ/4 elevated radials
> at least 10' high is kind of doubtful.
>
> One of my 10' high λ/4 elevated radials was almost straight N, and the
> other one was bent at crazy angles to the S because the neighbor's fence
> was too close.
>
> 73, Mike
> www.w0btu.com
>
> On Fri, Oct 19, 2018 at 5:01 PM  wrote:
>
> > Hi Mike,
> >
> > Yes that seems to agree with most writings.
> >
> > I hope soon to swap the two radials for an FCP to see what all the fuss
> is
> > about. See if its so much better as been told.
> >
> > I fell in love with TB after a recent trip to V31 when I worked some very
> > marginal QSO’s with JA, VK and Russia. Quite a sense of achievement as I
> > watched the greyline sweep across Europe.
> >
> > CW only I’m afraid.
> >
> > I did have an inverted-L over seawater so my TX was good, my Rx antenna
> > wasn’t usable. (Local aircon/floodlights)
> >
> > 73 Iain
> >
> >
> >
> >
> >
> >
> >
> > *From:* Mike Waters 
> > *Sent:* 19 October 2018 22:21
> > *To:* g4...@justfans.co.uk
> > *Cc:* topband 
> > *Subject:* Re: Topband: Mixed RF grounds
> >
> >
> >
> > Hello Iain,
> >
> >
> >
> > You heard correctly! My inverted-L with 2 elevated radial had no ground
> > rods except on one terminal of a spark-gap lightning arrester.
> Description
> > and photos at
> >
> > www.w0btu.com/160_meters.html (scroll down). You *must* also have an
> > effective common-mode feedline choke near the feedpoint.
> >
> >
> >
> > 73, Mike
> >
> > www.w0btu.com
> >
> >
> >
> > On Fri, Oct 19, 2018, 4:02 PM  wrote:
> >
> > Hi,
> >
> > In my limited garden I can get away with an 17 high inverted-L with 2
> very
> > bent elevated radials and very odd angles. One of them in the farmers
> > field.
> >
> > It has certainly got me out but I have been told if I sick some copper
> rods
> > down at the base and connect to the radials (coax shield and radials)
> this
> > is not going to be beneficial.
> >
> > This seems counter-intuitive.
> >
> > Before I get digging (cos I got to try it anyway and take some analyser
> > readings) can anyone comment on this?
> >
> > Iain G4SGX
> >
> >
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: trying to tune up 80 meter 4-Square

[Guy Olinger K2AV]

Essential point that might be missed: each one of the elements, one at a
time, must be tuned independently with the other three elements down. This
is the initial tuning. If when everything hooked up characteristics are OK
then you’re done.

Finish initial tuning and it's *not* OK? To slide the ARRAY center freq up
or down, there are several methods:

1) Redo the initial one at a time tuning with an opposite-to-the-error
adjustment to the one at a time tuning target frequency.

2) make *small*  identical wire length changes to all four elements at the
same time.

3) If you're an engineer and have the equipment and design software,
redesign the box to work with what you have. ☺

Just remember that the elements of a four square are very heavily coupled
to each other, regardless that all are driven from the control box. The
final result is a complex function of the driven current AND the effects of
the heavy mutual coupling between elements.

73, and good luck,

Guy K2AV




On Thu, Oct 11, 2018 at 8:15 PM  wrote:

> Yes, install ONE sloper. . .measure and cut to resonance.  Duplicate that
> measurement for the other three. 73. . .Dave, W0FLS
>
> -Original Message-
> From: Wayne Kline
> Sent: Thursday, October 11, 2018 6:03 PM
> To: terry burge ; topband@contesting.com
> Subject: Re: Topband: trying to tune up 80 meter 4-Square
>
> Terry,
>
>
>
> I assume  you only  installed ONE sloper and made your measurements ?
>
>
>
> With all 4 installed  there is  way to much mutual  coupling to get a
> meaningful reading.
>
>
>
> If your  readings were from only ONE antenna tuned with a length of 50 OHM
> cable at it’s feed point and trimmed to your desired  freq. and that FREQ
> will rise about 80 to 120 KC when the 4 are installed .
>
>
>
> Wayne W3EA
>
>
>
> Sent from Mail for
> Windows
> 10
>
>
>
> 
> From: Topband  on behalf of terry burge
> 
> Sent: Thursday, October 11, 2018 6:11:37 PM
> To: topband@contesting.com; terry burge
> Subject: Topband: trying to tune up 80 meter 4-Square
>
> Hello Guys and Gals,
>
>
> Recently Tree did some work for me and one of the things was to put up the
> Comtek 80 meter 4-Square switching unit and a couple of pulley setups for
> my
> raising of the 80 meter slopers. Lately I've been chasing my tail around
> to
> get them dipped in around 3700-3750 Khz. Been adding or subtracting length
> of the slopers to bring them into resonance but it seems the more I work
> at
> it the worse things get. Today I dropped back to punt by rechecking my Rig
> Experts AA-170 with a 50 ohm load just to make sure it read right...it did.
>
>
> The sloper dipoles are MFJ 1779B's 'trim to length' except one I had to
> rebuild with a hy-que center SO-239. RG-213 from the switching unit to the
> Rig Expert and when put together using a long run of LMR-400 about
> 175-200'
> back to the shack. 75 ohm DXE foam RG-11/u coax quarter wavelength stubs
> from switching unit to each dipole center. Each 75 ohm stub has multiple
> ferrite snap on's 5 or 6 to form current baluns.
>
>
> Here is an example. SE sloper, read SWR of 3875-3850 Khz of 1.0:1 in the
> shack on Elecraft W2 wattmeter. 3799 Khz SWR 1.3,  3775 Khz 1.4, 3750 1.5,
> 3725 1.5, 3700-3650 1.7...Added 19" each end and it seemed to read close
> to
> the same resonance!  Added 24" more each end and this time used the Rig
> Experts to check it out. Got two dips but not even where I was expecting
> them
>
>
> Resonacne 4680 KhzSWR 1.16
>
> RL 23.3 dB  |Z|   57.4 ohm
>
> R:  57.5 ohms  X: 10.7 ohm
>
>  C:  52000 nF up and down
>
>
> R::  57.9 ohm XLL  -4878 ohm
>
>
> second dip at 2169 Khz  SWR  1.07
>
> RL 28.0 dB   |Z|  46.5 ohms
>
> R:  46.5 ohms   x:  0.2/0.4 ohms
>
> L:  2.2 nH
>
> R::   46.4 ohmX||  (infinity or very high)
>
> L:||  same infinity
>
>
> And the frequency where I was trying to drop down from when I begain this
> morning
>
>
> 3860 Khz
>
> resonance now 3984 Khz   SWR  1.8:1
>
> R:  10.9 dB |Z|  27.9 ohms
>
> R:  27.9 ohmsx: -0.1
>
>c: infinity
>
> R||  27.8 ohmsX||  -48000 up and down
>
> C||  8pF
>
>
> How can I add almost 4' of wire on each end and not drop the resonance
> down
> a couple hundred Khz? What is with the two dips way above and below where
> the 128' sloper should be resonating? That is an approximate length since
> by
> this time and several days of adjusting I'm not sure what each dipoles
> length are. Since I have a 40 meter dipole near the slopers I tried
> raising
> and lowering about 10-15' up and down but it did not seem to change much.
> I'm beginning to instinctively cringe each time I have to tune up an
> antenna
> because this is what I know I'm in for. Especially with dipoles!
>
>
> After all this I just made another run of the SWR across the band with the
> SE sloper.
>

Re: Topband: Inv L in Tree

[Guy Olinger K2AV]

Hi, Ed,

Taking the vertical wire up next to the tree trunk will be fairly lossy.
That usually also means that some part of the horizontal wire is going
through the tree canopy, which will be further lossy. See k2av.com . Click
on the green index button "Place an Inverted L". Also read "Design an
Inverted L", "Place an FCP" and "The Loss List". Note the issue with not
having trees (or parts of them) "inside the bend" of the L. Read them all
with an eye to understanding the loss issues.

There certainly are situations where a variety of local constraints will
make the most efficient method otherwise inadvisable, e.g. wire in
neighbor's tree not being seen. :>))  Oh, what an enormous advantage are
great relations with the neighbors!

But, while you are the only one who really knows what you can and can't get
away with, if you know what causes RF loss in an antenna, then you are also
the only one who can muse on the problem for a while and invent a variation
in the arrangement that stays within your local restraints **and** avoids
most or all of the loss.

Let me know off-reflector if you want to discuss this over the phone. That
is sometimes a lot more direct and far less time consuming than email.

In any event, good luck with it & 73,

Guy K2AV

On Sun, Sep 23, 2018 at 1:39 AM Edward via Topband 
wrote:

> Has anybody snaked a wire up a tall tree trunk to make an Inv L?
>
> Any interaction?  Success??  Has to be stealthy because the tree os my
> neighbor's :-)
>
> Thanks,
> Ed NI6S
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Air Wound Coil

[Guy Olinger K2AV]

Hi Rick, Wes,

I said it was a "killer piece of copper". I did not compare it to anything.

Mostly I like the way that edge-wound coil looks (what was on my mind when
I said "killer") The same way I like a lit up and glowing red 3-1000Z
putting out 1500 watts, or the spooky glow of 866A's and 872A's back in the
day. That's three "killer" tubes :>))

I have some vague recollection of the current on thick, flat conductors
having non-uniform tendencies giving it some non-intuitive aspects. If I
was going to have to do something careful, I'd have to so some digging to
see what that was all about. What both of you proffer seems familiar,
though from subsequent posts is in varying dispute when you get down to the
nits in the issue.

Since you bring it up, the edge-wound coil certainly does dissipate more
heat, and it's sometimes needed. Not all antenna problems can be handled
well by a given tuner configuration. And for the unfortunate antenna/tuner
combination where physics reduces the possible tuner efficiency by putting
heavy current through the coil, it's nice to know the silly coil won't burn
or melt it's supports.

I've certainly done the latter with the coil stock back in the early days
when I still had hair and didn't understand the high RF currents sometimes
involved in TX tuning circuits. The circular shape of the wire in coil
stock wasn't enough counter-influence to keep it from heating the
polystyrene support rods past melting.

The one that is still funny in my recollection (though not at the time),
was done running only 750 watts out (old rules 1000 watts input on CW) on
80m. The droop on that, before it started shorting and got my attention,
was spectacular, and I also made the mistake of touching the melted
polystyrene.

It was an open vertical breadboard matching network connected to 40 feet of
RG-17 that was connected at the other end directly to two ground radials
and an end-fed 133 foot wire. The coil stock was mounted horizontally and
only at the ends. I don't remember what the circuit was at this point, but
in the end it was clear the happenstance 1/4 wave transformation from the
RG-17 set up some considerable RF current in the coil stock. Thereafter the
coil had a "smile" in it.

Thus far I have not managed to melt or burn up my ATR-30 which uses the
aforementioned "killer coil".  :>))

73 folks,
Guy K2AV

On Thu, Aug 30, 2018 at 10:34 PM Wes Stewart  wrote:

> I agree with Rick.  The advantage to the edge-wound inductor is the better
> heat
> dissipation; needed because the Q is lower :-)
>
> Wes  N7WS
>
> On 8/30/2018 5:44 PM, Richard (Rick) Karlquist wrote:
> >
> >
> > On 8/30/2018 3:44 PM, Guy Olinger K2AV wrote:
> >
> >> You can also get the edge-wound (flat) 1/4 inch by 1/16 inch coil that
> they
> >> use in the ATR-30 rotary coil tuner. That's a killer piece of copper.
> >>
> >
> > Actually no.  Edge wound is inferior in terms of Q to round wire.
> > It only makes sense for a rotary coil, where it needs to be edge
> > wound for mechanical reasons.  On a flat strip, the current
> > crowds to the two edges for the same reasons that cause skin
> > effect, thereby wasting most of the copper.  Round wires are
> > immune from this because they have no edges.
> >
> > 73
> > Rick N6RK
> > _
> > Topband Reflector Archives - http://www.contesting.com/_topband
> >
>
> _
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>
_
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Re: Topband: Air Wound Coil

[Guy Olinger K2AV]

The referenced Ameritron/MFJ part number is an 11 inch coil (aka BMW coil
stock of old), coil wound into 4 polystyrene rods. This one is 3 inches
diameter, four turns per inch, 10 AWG tinned bare solid copper.

This stuff is used in various Ameritron amps as part of the output Pi-L
networks. I have found that it's very touchy to cut sections for specific
lengths. The trick is before cutting anywhere on the 11 inches, across the
whole coil use a tiny drop of Krazy glue, or its equivalent, on both sides
of the wire at the points the wire is melted into the polystyrene rods.
This really stiffens up the "feel" of the coil. Then cut the wire first and
then the rods with a Dremel tool for specific needed lengths. I bought two
of the 11" lengths the last time, which should last me for a while.

Seems to me it was back-ordered for a couple months. They have to
manufacture a batch. And they are not going to undercut the coil on site
needed to manufacture their amps.

You can also get the edge-wound (flat) 1/4 inch by 1/16 inch coil that they
use in the ATR-30 rotary coil tuner. That's a killer piece of copper.

Good luck all.
73, Guy K2AV

Dunno what you guys do from across the pond to speed it up.

On Thu, Aug 30, 2018 at 5:55 PM Jim Thomson  wrote:

> Date: Thu, 30 Aug 2018 07:44:04 +0100 (IST)
> From: MR TREVOR DUNNE 
> To: ''topband List' 
> Subject: Topband: Air Wound Coil
>
> 
> I'm looking for an Air wondering coil like in this link,
>
> http://www.mfjenterprises.com/Product.php?productid=404-0669
>
> I've had one on order from MFJ via a UK company for 4 months now and no
> sign of it, I want to build a at matching network for my 160m inverted T
> using it or something similar,
>
> Can anyone tell me where I can get one of these or similar that is in
> stock today,
>
> I don't have access to the tools/parts to wind one my self,
>
> Thanks
> Trevor
> EI2GLB
>
>
> ###  That mfj coil is listed as a whopping  79 uh  !I cant  see having
> to use anywhere near that  value  for a simple   160m  T  ant.
> I calculated the  value for a buddy a few yrs back, for his  160m  T
> vertical, and it was no where near  79 uh...just a few uh.It was easy
> to wind by hand.
> The ant was resonated a bit on the high side, so the  Xc  of the ant + the
> coil  formed a step up  L network.  No different than using a
> beta match or hairpin on any mono band yagi.   Think we used 8 gauge
> wire..  which is  .128  copper.   It was freestanding, after being removed
> from the
> form used to initially wind it on.   Coil was oriented  vertically..and
> placed  right across the feed point.  Then the vert is also DC grounded.
>
> Jim  VE7RF
> _
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>
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Re: Topband: 160 sloper readings

[Guy Olinger K2AV]

Hi, Gary.

It is not clear from your description exactly how the "sloper" is fed,
where the radials are in relation to the tower, etc.

Quite a few things could be responsible for a change like that.

Not clearing the leaves off the ground over the radials will gradually bury
them and result in a slowly increasing feed R and loss.  Clearing the
ground through each leaf fall period with a leaf blower usually clears that
up. You will note that in areas subject to seasonal falling leaves, AM
broadcast antennas have huge nicely mowed lawns over their radials, and
trees have been removed from the radial field. That is not without cause or
entirely for appearances. Buried bare radials will behave differently over
time than insulated radials laid on top of the ground.

The tower and all the wires running up it are HARD-coupled to the sloper.
It is possible to have more RF current in the tower and its cabling than in
the sloper wire. It is possible for the tower and its cabling to be the
major radiator/dissipator of the tower/sloper *system*.

Adding or removing cables on the tower, or changing the terminations of
conductors, if they are not all bonded (or capacitor-RF-bypassed) to tower
at top and bottom, will change the feed measurements. Exactly how the
measurement changes, and how much it changes, depends on environment and
grounding/blocking on those conductors.

Adding/changing/removing yagi's, etc near the top of the tower will change
the "parasitic element" behavior of the tower as seen by the sloper.

Particularly if the ground is poor, simply having a rainy summer can change
the feed Z of the sloper.

Deterioration of the radial conductors can raise the feed Z of the sloper.

Installing a new antenna/feedline or tower within a half-wavelength radius
or so can alter the feed Z of the sloper.

Folks often throw up a wire from a brief description of an antenna, and are
happy if they can work QSO's. Considering how often time and funds for ham
projects are simply not available, I can hardly argue with this, and I
won't, having done the same myself, quite for cause. I will note that
getting on the air on 160 is one thing, and worrying about the
characteristics of a thinly engineered antenna, and that over most of a
decade, is quite another.

The "time-lapse engineering" of the antenna may not have been considered at
erection time, and deterioration may have started the day after the
antenna's erection. It is unusual for a ham to have an academic grade
recording of frequency sweeps and various measurements taken at routine
intervals, along with dated notation of changes made to the antenna farm.
It's not like a pilot's log or aircraft maintenance log which is required
by law, and punishable if omitted. Almost *nobody* has this data, making
explaining over-the-years-changes really difficult.

Allowing leaves to accumulate may be highly preferable from an appearance
or maintenance effort standpoint, but will gradually deteriorate TX antenna
performance. This is an annual problem for those with BOGs in the woods.
After two years, the bottom layer of leaves will have completely decomposed
into soil or proto-soil, effectively burying the radial wires deeper. Six
or seven years is worth half the years in inches further buried. This
softer more permeable, sponge-like new layer will get criss-crossed with
the grateful roots of anything growing in the woods. At the same time this
adds more dielectric material inside the ad-hoc capacitor that is the
sloper wire vs radials. If not increasing loss, the additional dielectric
material has at minimum increased the feedline shunting capacitance of this
ad-hoc capacitor, dropping the resonant frequency.

Given everything above, it's not at all unusual that you would have
experienced changes. Rather more it was guaranteed that you would
experience changes. One of the blessings of elevated radials or an FCP is
the 8 foot separation between constantly changing lossy ground and the
system consisting of bottom of the vertical wire plus counterpoise.

You may want to revisit the choice of 160 antenna.

73 and good luck,
Guy K2AV



On Sat, Aug 18, 2018 at 7:17 PM Gary Smith  wrote:

> Folks,
>
> I'm starting to get ready for the upcoming
> winter frolics on 160. The 160 antenna is
> a sloper and I have somewhere around 50 or
> so 130' radials pretty much buried under
> 6-7 years of leaves. When I went to the
> remote coax switch & checked the readings
> on the sloper with 10' of coax, I found
> some readings with the old MFJ-259B that
> concerns me.
>
> I thought I'd cut the Sloper at 129' long
> for best SWR at 1.825 but I'm now reading
> the lowest SWR at 1.737 MHz and the
> impedance read 85. Going back to the shack
> I read the antenna (with 360' of 7/8 50
> ohm commscope now in-between), and the
> resistance drops to 55 but the SWR still
> reads lowest around 1.737
>
> It appears I need to shorten my antenna,
> I'll have to work out the proper length
> again but my concern is 

Topband: 160 is coming back

[Guy Olinger K2AV]

160 is coming back from 2, maybe 3 weeks of doldrums and not making it over
the Sierras, or tickling Europe.

RBN's tickled from CWT on 160 2345 to  Wednesday night local

Hits to the east: OL7M
Hits to the west: N7TR(2) VE6WZ(3) N6TV VE7CC AC0C

Also hearing buoy signals on 1828. AU8 was S8.

Didn't sound like a dead band to me, just noisy.

73, Guy K2AV
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Several BOG questions

[Guy Olinger K2AV]

Hi Mike et al,

BOGs have a well deserved reputation for being cantankerous, with great
results for K4ABCD over here and awful results for K3WXYZ over there. There
is a part of the explanation for that variation that really isn't fixable.
But better outcomes are possible with a more detailed explanation of how a
BOG works, and understanding its significant differences with a standard
beverage RX antenna.

First off, a normal beverage will have a velocity factor (VF) of ~ 95%,
maybe a little more if it is high. That means that the VF can be ignored,
and all the well-documented regular beverage understandings and procedures
apply. However...

When you put the wire on/in the ground, notched below the grass, etc,
**measured** VFs in my area have ranged anywhere between 45% and 85%. This
means a lot we understand about a beverage antenna does not apply. We
measured VF by finding the resonance of a 151 foot (46 meter) dipole on
ground (DOG), laid in the same place and manner as an intended BOG.

The most common VF's were in the high 50% range. The values did not seem
related to any local factor easily exposed. There were times when rotating
the DOG around the center 90 degrees made a large change in VF, even though
the owner of the property insisted there was no piping, cable or drainage
fields beneath and nothing overhead. Presumably exact composition of dirt,
rocks, and varying water table or water presence, were responsible. This in
turn varies the response to the specifics from site to site.

Modeling a BOG in NEC4 exposes the issue: the incident incoming RF is
traveling at almost speed of light, and the RF already collected at a given
point has traveled on the wire at only half that. A physical quarter wave
of wire on ground appears roughly like a slowed down half wave. This causes
RF energy on the wire from the far end to be nearly out of phase with
incident RF near the feedpoint. BOG lengths beyond 250 feet can actually
start to reverse their pattern at higher frequencies. This makes a BOG a
one band antenna for front-to-back.

220 feet terminated by a pair of those 450 ohm beverage termination
resistors in parallel usually seems to do "passable" for a quick
slam-it-down-and-go-operate-in-a-contest five minutes later. But neither
length or termination is predictable to anything like the same degree as a
normal beverage.

A BOG is lossy. Frequently a BOG will work better with a
properly-feedline-isolated remote preamp.

A decently-centered BOG with a modicum of F/B can be had by first
installing it as a DOG. If you live in a primarily arid area then do this
exercise when it is dry. If wet or damp is common in the 160 "season", do
it in a wet time, so the ground is NOT dry.

Operating later, if things have gone dry, if you installed it in the wet
you can always go "water the BOG" before an important operating event.
W0UCE referred to this ritual as "water the boggies".

To create a location specific BOG, using 1.825 MHz as center:

Starting with a 250 feet length of PE or teflon insulated wire, lay the
wire out in the exact line and manner as you intend for the BOG. Bend the
end tips of the wire up an inch in the air so they don't short to the
ground. Break the center of the wire and temporarily attach an SO239. You
have created a DOG which you will now prune to vagaries specific to your
location and placement.

Use your RF analyzer at the center to find the lowest frequency resonance,
which will be well down in the AM broadcast band somewhere. The R where X=0
will usually be anything from 100 to 250 ohms. This is not critical.

***Trim equal lengths from the ends*** to move the resonance (X = 0) up to
1140 kHz (one point one four zero MHz). R is immaterial. Don't get in a
hurry, the effect of cutting off a foot (6 inches both ends) is often not
linear because the instant VF at a point on the wire most often is NOT
uniform across the wire. Only when you have trimmed the DOG to 1140 kHz in
this manner, reconnect and re-insulate the center, and only then place feed
transformer, termination and run feedline. A BOG done in this fashion will
have a predictable pattern (for a BOG) which makes best use of the fast vs.
slow RF velocities involved.

A ground of two equal length 40, 50 foot bare wires notched 2, 3, 4 inches
into the ground at right angles to the main wire will do as well as needed.
50 feet either way seems to be enough, though this is a very fuzzy length,
and will never be precise. Terminate the far end with 225 ohms (two 450's
in parallel) to ground. Less than 40 feet may start to lose signal transfer
to the feed transformer increasing an R in series with the primary winding.
But do what you can

In poor ground, a short ground rod by itself might be an adequate
termination. This provides a termination by providing a very resistive
ground, quite unsatisfactory for other applications. You need SOME
termination R, but the value is not critical. Any precise F/B with variable
R listening to a back side 

Topband: Summer, but 160 ain't dead

[Guy Olinger K2AV]

During the last 15 mins or so of CWT, stations worked on 160 included:

on the east G4UFK, not in test.
on the west N6RO

Western RBN's VE7CC, VE6WZ, NC7J, east spot (not RBN) ON7PQ.

Don't sound like a dead band to me. Some number of signals were better than
20 over.

If you're starved for 160 time, get a CWOPS number and show up on 160 the
last 15 minutes of the 0300-0400Z segment (Wednesday nights US local time,
Thursday AM Zulu.) Exchange is name and CWOPS number or name and state
without one.

Activity is generally 1827.5 and up

Get to play around a little bit. Work on stuff and test it out, etc.

73, Guy

K2AV
CWOPS 1671
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Fwd: Re: Baker Island DXpedition on 160

[Guy Olinger K2AV]

Methinks hamdom underestimates 160 propagation in the summertime.

Working DX through QRN and having reduced opening time during summer, these
make working the DX irritating to the ears and inconvenient, but not
impossible. Even with no more than an inverted L, I still hit European RBN
later in the evening, and routinely hit west coast RBN that are not covered
with lightning strikes on Blitzortung. That's not so much my antenna, as
the fact that 160 is a lot more open in the summer than people think. If
there's no good reason to listen to all that QRN, or set an alarm to be on
the band in the narrow darkness hours, they won't be listening.

Was on in the CWOPS last night (June 14, Z) on 160m, between 03 and 04Z,
RBN spots included:

N7TR *
G3WW *
WA7LNW
WB6BEE *
VE6WZ *
GW8IZR *
VE7CC
3V/KF5EYY *
AC0C *

*multiple spots

That's coverage Vancouver to Reno in the west and the UK to Tunisia in the
east.  Not exactly my definition of a dead band. Sparse 160 population in
the summer is a habit ham radio has gotten into. Maybe we should put that
aside for the rest of the solar minimum.

We'll be watching for KH1...

Summer Stew Perry Saturday night.

73, Guy


On Wed, Jun 13, 2018 at 1:33 PM, F Z_Bruce  wrote:

>
>
>
>
> 
>
> As in ARRL literature, even as short antenna in  a great ground plane  can
> be very effective.  The Baker Island  group has  indicated that  they were
> going to use the salt water..
>
> 73
> Bruce-k1fz
>
>
>
>
>
>
> On Wed, 13 Jun 2018 16:14:01 +, jon jones  wrote:
>
> Back in the 90's -  KH6ND was active from Kure Is on 160M during July. He
> was very workable in North America in the early morning hours before NA
> sunrise. I logged Mike with 100 w and my balloon supported vertical. QRN
> from thunderstorms may be lower at that time.
>
>
> Europe may well have some short windows of opportunity as well.
>
>
> A safe trip to the KH1/KH7ZZ team.  - Jon N0JK
>
>
> 
>
>
> Hello TopBanders,
> KH1/KH7Z will be active on 160 from Baker Island from June 27 to July 6
> (note that dates are tentative and may change -- please visit
> http://baker2018.net/ for updates).
> GL and CU,
> George,
> AA7JV
>
> PS: Donations are the life-blood of DXpeditions and this one is no
> exception.
>
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
> _
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>
_
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Re: Topband: Question for the K2AV FCP users...

[Guy Olinger K2AV]

Howdy, all.

<<>>

Peter's post here follows a direct inquiry some weeks ago that I was
unable to fully answer before now.

Wire mats connected to ground radials have been around a long time and
instances reported improving sparse on/in ground radial systems. So an
intuited extension to a mat on the ground beneath an FCP is quite
understandable. It's also a reach for many people to see the FCP as
anything but another kind of radial, just folded up to make it smaller
and get away using only one.

I get that. To be truthful, ten or twelve years ago, **I** would have
a really hard time believing the stuff on k2av.com. There was too much
deeply embedded contrary "traditional" understanding back then. W0UCE
and I had an occasional tough ride disentangling from the "wisdom of
the elders" getting to the understandings of the current day.

I still think that the FCP should have been invented some time in the
late 1950's. If my elmer had invented the FCP, I'd have had no trouble
absorbing it and weaving it into my plans, and you would have heard of
it long ago from some "revered" source. But sorry, you got me, and I
know I don't have the personal appeal of Mr. Rogers or Mr. Science to
ease a gritty informational transition with a fetching personality.

All that makes the question worth a careful, respectful answer,
however much a PITA the work to generate the associated confirming
math. The math work highlights pesky details that make a huge
difference in what a "ground screen" or "mat" does or does not do,
ground radials vs. FCP.

Digging deep into the question necessitated a pile of NEC 4.2 model
runs, some with more than 18,000 segments. Even with my 3 GHz PC,
model runs using high accuracy ground and the NEC 4 double precision
engine sometimes took 15 or 20 minutes to complete and post up
figures.

At some point, running the usual necessary sanity checks on results
exposed artifact issues with very small segments and close wire
spacing. I was starting to wonder if NEC 4.2 could actually do the
problem correctly.

Fortunately I had a flash of memory about the NEC 4.2 upgrade which
introduced "extended accuracy" ground, something about artifact fixes
in the new method. I reran in extended accuracy, and results started
clearing sanity checks.

So *everything*, hours and hours, had to be run all over again in
extended accuracy. The extended accuracy ground method can better than
double the program run time. So this has not been a simple or quick
question to analyze carefully. I've settled on 48 wires, notched 1/10
inch into the ground, 66 feet long, spaced one inch, directly
underneath the FCP. The 30 minutes plus for solution with mat is at
the limit of workable program run times in extended accuracy. I start
runs with the mat on the model and get up and go do something else.

<<>> The ground screen has no effect beneath an FCP.

I ran NEC 4.2 with and without a ground mat, over extremely poor
ground (.001,3). *With* the mat on ground the program computed average
3D gain at -6.25 dB. *Without* mat on ground returned -6.27 dB. Two
hundredths of a dB difference in the results is probably correctly
dismissed as "noise". If it was precise it would be the difference
between 355.7 and 354.1 watts left from 1500, not discernable on
analog power meters. Using "ghastly ground" (.0005,1), returned -7.63
vs -7.66 dB, or 258.9 vs. 257.1 watts.

With either set of ground constants, the NEC 4.2 "with" and "without"
plot patterns were identical. The differences in the overlaid plot
values were less than the width of a pixel. Expanding the overlaid
traces to a foot across on the monitor did not show any divergence.

Ghastly ground (.0005,1) is what I call the ground description,
deliberately chosen, that causes the most loss in NEC antenna
calculations. It is used to super-emphasize ground sensitivities, and
make sure solutions work and are optimized over the oh-so-common urban
and suburban poor, very poor and extremely poor ground. This yields
solutions that possibly somewhat uncritical with "average" ground, are
centered in the narrow optimum solution ranges often found with poor,
very poor and extremely poor ground.

K0RF (and a co-conspirator whose call I can't find in any of my email)
ran an interesting test at 160 MHz over an MFJ VHF RF analyzer. They
built two inverted L antennas from SO239 chassis connectors and #12
bare wire. One was over four quarterwave radials. The other was over
an FCP. The feedline was coax adapters from the MFJ to the SO239.

The MFJ stood upright. Each individual antenna's feed characteristics
were observed while a large copper sheet was pushed underneath the
MFJ. The meter indications on the L over 4 radials displayed a large
variation between "with" and "without" the copper sheet. On the L over
FCP, the readings did *not* change between copper and no copper. This
demonstrated the FCP's deliberate design to minimize net counterpoise
fields at ground.

<<>>

As far back as 1937, Brown, Lewis and 

Re: Topband: Wednesday 160m DX Activity Night

[Guy Olinger K2AV]

Hmm, this last week was still hitting RBN over there, and worked G3OLB
two different days a little before his sunrise. One of those was a
long lovely old time 599 QSO with Tom, like I was working someone in
Ohio on 80 meters.

It might be "season" over, but 160 sure isn't over, at least not yet.

I think a lot of people don't get on unless there is an "event". Or
unless they hear a lot of signals.

I remember when I was a kid and we had "marbles" season**. Everyone
started showing up at school with marbles in their pocket. Then one
day nobody had any and marbles season was over. We COULD have played
marbles for another month until school was out for summer, weather was
fine for such things most days. Just that nobody showed up at school
with any marbles after "marbles season" was over.

Waste of perfectly good propagation.

Hmm, CWops tonightlast ten minutes...

73, Guy.

** https://en.wikipedia.org/wiki/Marble_(toy)

On Mon, Apr 23, 2018 at 12:40 PM, Ed Sawyer  wrote:
> Roger.  My guess is that it is considered "season over" by most of the boys.
> I rarely get on 160M after early April unless there is a specific DXpedition
> on.  I don't think I am alone.
>
>
>
> In some cases, people even lose antenna options for the summer due to
> coexisting with farmers and other activities.
>
>
>
> 73
>
>
>
> Ed  N1UR
>
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
_
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Re: Topband: 80/160?

[Guy Olinger K2AV]

Hi, Jim,

The problem in your proposal is that the location of the relay must be
the highest possible voltage on 80m. You need 20 kV maybe more at QRO.
There is a better way to get 80/160 off the same wire. The trap still
leaves you with a 1/4 wave vertical that takes no advantage of the
rest of the wire.

The better deal is to do all the work at the bottom and feed an
existing 160 1/4 wave inv L as an 80m end-fed halfwave L (EFHWL). The
80 EFHWL is probably the best all around 80 m single wire antenna. An
80 EFHWL will significantly outperform an 80 1/4 wave vertical.

80 EFHWL’s are not wildly popular because you can’t feed them directly
with 50 ohm coax and no one makes a commercial box for the base.

No one makes a commercial box for the base of an 80 EFHWL because the
80 EFHWL is not wildly popular.

You can do an 80/160 which makes use of an UNMODIFIED 160 inv L over
FCP.  Relay at center of FCP changes way FCP is fed when set for 80m.
No changes to aerial wire or FCP per se. All the tuning circuit for
dual banding is near the ground and circuit can accommodate multiple
SWR ranges/center freqs on 80/75.

This is discussed on k2av.com in the 80/160 Dual Band indexed section.

Tested this design in 14 hour 2016 CQWWDX CW effort at K2AV, official
SOSB(A)/80 score: 266 Q's 18 Zones 77 Countries, good enough for #2
North America (QTH in North Carolina, not New England) and a top
scores listing in the CQ magazine article. Also, in the 2017 ARRL SS
CW, worked 403 QSO's on 80 meters alone, one of only three stations in
the contest to work more than 400 QSO's on 80 meters.

An 80 EFHWL works very well and avoids altogether several loss factors
which bedevil 80m 1/4 wave verticals.

Rather than current maxima at the ground, the EFHWL has the advantage
of current maxima up at the bend, a significant reduced loss
advantage. The half V half H wire polarization puts out a
hemispherical pattern, which has no weakness at azimuth or elevation.
There's no doughnut hole at the upper takeoff angles, and still is
never less than the 1/4 wave at the low angles. This means you do not
have skip zones on 80 unless the band has gone way out.

It 's about time that the 80 EFHWL got some deserved good press.

73, Guy K2AV


On Wed, Apr 18, 2018 at 1:34 PM Jim Miller  wrote:
>
> Rather than use a trap at the top of an 80m vertical to transition to a 160
> inverted L has anyone tried a vacuum relay or even two in series at 1500w
> to handle the highvoltage when on 80m?
>
> Tnx
>
> Jim AB3CV
> _
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