Re: Topband: TT8XX QSL Help

[Richard (Rick) Karlquist]

I read somewhere that Glorioso is a military base and all operators have 
to be French military personnel.  Possibly, the limited pool of

potential operators didn't include CW operators of DXpedition caliber.
CW, unlike digital modes, actually requires skill, and considerable
skill for DXpedition operation.

73
Rick N6RK



On 4/26/2024 4:51 PM, Don Greenbaum wrote:

digital, or even voice, but only CW?? No, of course not; that's fair 
game, to me, since my only interest is CW, and who needs those other 




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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: HEBA antenna

[Richard (Rick) Karlquist]

No one has commented on the "High Efficiency" "Broadband" claims, so I 
will.  No antenna of this size will simultaneously have both high 
efficiency and wide bandwidth, according to established limits in the

literature.  See K6OIK's Pacificon paper with the latest refinements
to these limits.  Additionally, narrow band antennas typically don't
handle a lot of power.  I doubt that this would be extensible to 50 kW.
not that it matters for ham radio.

When placed over ground, even with an elevated counterpoise, there
would still be ground losses, which would affect efficiency.

Also, although the antenna technically only occupies 1/8 acre, the
fields will be very high within 1/6 of a wavelength, about 50 meters
at 1 MHz.  This covers 2 acres.  I know my 90 foot 160m vertical,
complete with guys, ground screen and top loading wires neatly
fits within a 100 foot radius circle. about an acre.
What's not to like about this?

Rick N6RK

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Re: Topband: [TowerTalk] New N6LF Ground Probe Designs

[Richard (Rick) Karlquist]

On 3/2/2024 11:36 AM, Jim Brown wrote:

On 3/2/2024 10:43 AM, Jeff Blaine wrote:
I live in an area surrounded by farm lands and assume that the soil 
here is nice and conductive.  But I have no idea what that really means.




There is no definite correlation between land being farmed and RF 
conductivity.  My QTH is classified as "Class 4" soil for Ag.

purposes.  That's the LOWEST rating.
It is 100% clay from the surface down to 40 feet.
There is a water proof hard pan layer down a foot or so below
the surface.  Even weeds don't grow well.

Yet, it evidently has high RF conductivity.

I'm not saying you couldn't have land that is good for both farming
AND RF.  But the two don't always go together.

73
Rick N6RK

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Re: Topband: [TowerTalk] New N6LF Ground Probe Designs

[Richard (Rick) Karlquist]

On 3/1/2024 10:44 AM, Brian Beezley wrote:
Rudy Severns, N6LF, has updated his writeup on ground parameter 
measurement with several new probe designs. A ground probe and NanoVNA 


I'm not trying to take away anything from Rudy's excellent work, but he 
doesn't explain in the posted article what useful advantage we can

derive from the measurements.  It only gives a spot measurement of the
top foot of soil.  And the soil that matters is the soil at large
distances from the antenna.  It is unlikely that this probe could be
used to survey all that area of land that isn't owned by the ham with
the antenna.

Also, I would prefer Rudy's previous method using a low 1/2 wave dipole.
It covers more area and presumably would penetrate into the soil more
than a foot.

Another thing I would prefer is to simply put up a vertical and a dipole
and A/B them for signal strength on various RBN stations.

Finally, it is also possible to build a Beverage antenna and run
a current probe along it as I have done and determined how fast
it attenuates with distance.

I know very well that my QTH is over highly conductive ground without
ever using an OWL probe.

73
Rick N6RK

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Re: Topband: Lack of DX CW Activity

[Richard (Rick) Karlquist]

On 1/6/2024 6:49 AM, Mike Smith VE9AA wrote:



Bill  KU8H

  


OK, I'll be very honest and say that I don't really understand posts like
this.

For nearly 30 yrs I've run 160m mobile on again/off again (more off than on)
and have I think 67 countries on Top Band.



KH6DX/W6 famously worked 100 countries for his DXCC ... from his pickup 
truck in SoCal.  He had a big fat screwdriver antenna, and an 800 watt 
amplifier.  He was at liberty to get away from noise sources, and get up 
on hills, drive on beaches, drive on dry salt lakes, etc and not have to 
run QRP to keep the neighbors happy.  One winter he drove to the N. 
Dakota/S. Dakota border and worked the ARRL 160 and had a blast.  He was 
plenty readable on this coast from 2,000 miles away.  He even had 
special QSLs printed.


You mentioned the helically loaded PVC pipe that was published in QST.
That may have worked after a fashion, but an old fashioned loading
coil always works better than helically wound.  Your suggestion about
top loading wires is right on, though.

73
Rick N6RK

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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: NCC-2 antenna pattern?

[Richard (Rick) Karlquist]

I did exactly the same thing as what Tree describes.  It worked pretty 
well using just a Kenwood TS-570 as the 2nd receiver.  Getting a really

deep null on the loop requires attention to various details:

1.  RF leakage into the feedline
2.  Nearby metallic objects messing up the pattern of the loop
3.  The loop must be fairly small for a good null
4.  The so-called "N6RK loop" with varactor tuning cannot be used as is. 
 Instead, fixed capacitors must be used to tune it.


It was somewhat debatable as to how much the SO2R operation improved my 
contest score.


Rick N6RK

On 12/17/2023 11:12 AM, Tree wrote:



I have been successful with in-band receiving on 160 with a loop antenna
about 800 feet away from the TX vertical with the null parked on the TX
antenna.  On 20 meters, I have done it with about 500 feet separation.
It's obviously a lot easier with low power (like used in the NAQP).  The

Tree N6TR



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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Solar Cycle 25 Update - Presented by Carl Luetzelschwab, K9LA

[Richard (Rick) Karlquist]

Will this presentation be recorded?  Kind of early for us on the left 
coast who work.


73
Rick N6RK

On 11/13/2023 2:07 PM, Robert Urban wrote:

Please join us and our special guest speaker for the Madison DX Club
program on *Tuesday,  7:00pm **CST**:*



*The Madison DX Club's November 14, 2023, Meeting:*

Solar Cycle 25 Update - Presented by Carl Luetzelschwab, K9LA

Cycle 25 is producing many more sunspots than originally predicted.
Find out how this will affect the Amateur Radio bands for the next few
years.

Time: Informal chat starts at 6:00 PM CST,  Business Meeting at 6:30 PM
CST,  Program at 7:00 PM CST.
*UTC Time: Informal chat starts on **15 November** at z , Business
Meeting at 0030z , Program at 0100z **.*

*Visitors and guests are always welcome at MDXC meetings!*



Hope to see you all on Zoom, Tuesday evening.

*Kevin Shea, N9JKP*

*President, Madison DX Club*

*n9...@arrl.net *

Web site: Madison DX Club 



To Join Zoom Meeting:

https://us02web.zoom.us/j/8561554523?pwd=MFE3d1dXYWc1MGw4MDZtSEZ4bEp6Zz09=addon


Meeting ID: 856 155 4523
Passcode: 198101
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Re: Topband: Digiwave feedline

[Richard (Rick) Karlquist]

Have tested a bunch of coax from HD and Lowes, I would say it is some of 
the worst coax you will find.  It goes by various meaningless "brand" 
names.  I've never heard of "Digiwave".  I recommend you return it for

a refund and buy real branded coax from a real distributor (probably
on line since you are living on an island.)

Also, you want to get gel filled coax so critters don't chew it.
Can't get that at the big box stores.

73
Rick N6RK

On 8/10/2023 5:34 PM, Radio KH6O wrote:

Colleagues,

I purchased a 500 foot roll of Digiwave coax via Home Depot. It's
double shielded (braid and foil) and is sweep tested up to 3.5 GHz.
I'm unable to determine the country of origin.

Any comments on short runs of Digiwave feedline for HF or VHF?

73,
Jeff KH6O
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Re: Topband: Bugs

[Richard (Rick) Karlquist]

On 7/6/2023 10:38 AM, w3...@roadrunner.com wrote:

I stepped up to a keyer from my Lightning Bug in the early 90s' but
could never get the hang of both. My fist kept wanting to do the bug
W3HKK (since 1956)


First of all:  "its not your fault"

There are many different keyers available, and then there are
single and dual action paddles.  Some keyers have multiple
personalities to choose from.   This is a huge topic to
try to wrap your mind around.

The reader's digest version is that you can minimize the learning
curve by using a single action paddle.  This largely eliminates iambic
action (which you won't miss), even if the keyer supposedly supports
iambic.  Some built in keyers in rigs have an option to select
"A" or "B" iambic type.  On one rig I had, I absolutely could not
send with one of these selections, but the other one worked
fine for me.  On my current rig, A and B seem to be the same.
I only use a single action paddle (IE, "dot" and "dash" are
mutually exclusive).

Hope this helps.

73
Rick N6RK

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Re: Topband: Top Band Frequencies

[Richard (Rick) Karlquist]

On 7/4/2023 1:18 AM, Karel Matousek wrote:

I highly recommend please do not use the exact frequency of the 
transmitter to two decimal places with TWO ZEROs such as 1825.00 or 
18031.00 but rather e.g. 1825.33 or 1831.75.

Those exact frequencies are much more likely to have interference.
73, DX Karel OK1CF



Here in Region 2, the BCB stations are on 10 kHz multiples, so there
are always birdies on 1800.00, 1810.00, 1820.00, 1830.00, etc.,
so those should always be avoided.  OTOH, I have often operated on 
1825.00 and never heard a birdie there.  In the other regions, the BCB 
stations are on 9 kHz multiples, so it is likely that there are
always birdies such as 1800.00, 1809.00, 1818.00, 1827.00, so those 
should similarly be avoided.


Aside from that, on any band, any frequency that is a multiple of 5 kHz
is a risky choice for a contest run frequency, just because those
frequencies are more likely to be occupied, possibly by stations in
your skip zone.  Now, THAT is something I have experienced on 1825 in
contests.  It sounds clear, but then the band opens up and I find it
is already occupied.  It's not physics, but just human nature to pick
a nice round number for the frequency.  Resist that temptation, hi.

Rick N6RK

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Re: Topband: [PVRC] 2-element receiving arrays

[Richard (Rick) Karlquist]

On 3/30/2023 7:47 PM, Frank W3LPL wrote:

Hi Dave,

Anyone who has experimented with a high impedance antenna such
as an end fed half wave has experienced the extreme environmental
influence on the feedpoint impedance of a high impedance feed.

The required spacing to trees and buildings is very difficult to predict
with any confidence. The impedance of a high impedance element
-- and hence the amount of voltag if feeds into the preamp --
is heavily influenced by its immediate environment.

If all of the high impedance verticals in an array do not produce the
same voltages from the signals received by the array, the pattern
of the array and especially its nulls are significantly degraded.

73
Frank
W3LPL



Allow me to quibble a little with this analogy.  The 1/2 wave dipole
is a tuned circuit with a Q in the low double digits.  This leverages
any capacitance change.  The voltage probe antenna is just a plain
non-resonant capacitance.  Still sensitive to nearby conductors, but
probably not to the extent of the EFHW antenna.  I would be more
worried about circuit capacitance in the hi-Z preamp.  In general,
the capacitance of JFET's (or any FET's) is very loosely specified.
The transconductance is also very loosely specified, and can
act as a modulator of input capacitance due to the Miller effect.
As if that isn't bad enough, the DXE preamp comes with tank circuits
that you can optionally activate with jumpers.  This adds another
random variable to the input capacitance.  Ideally, there would be
a "factory select" padding capacitor to make the capacitance the
same on all copies of the preamp.  AFAIK, no preamps have this
feature. And finally, the CB whip moves around wildly in the wind.
If there are nearby objects, this adds a time variability.

73
Rick N6RK
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Re: Topband: 2-element receiving arrays

[Richard (Rick) Karlquist]

On 3/30/2023 5:54 AM, Pete Smith N4ZR wrote:
Thinking ahead to next winter on 160, I'm interested in replacing my 
K9AY Loop with a 2-vertical phased array.  I'd like to homebrew the 
antennas and just buy or build the remote control unit for the shack. 
I'm looking for sources of components (antenna-located preamps and an 
in-shack controller), and would prefer not to completely homebrew them, 
but the prices at the usual suspects are awfully high.  Any ideas?


I have pretty reasonably-priced access to 25 and 31-foot fiberglass 
poles (used for wind-socks by model airplane enthusiasts).  I'm thinking 
that one relatively low-cost approach might be to attach, say, #14 wire 
to the poles, with preamps at the base, but wonder if there is a 
downside to using such small-diameter antenna elements rather than 1 or 
1.5 inch tubing? Alternatively, are clones of the DX Engineering 8' 
short verticals with preamps a good alternative?




Answering your question about the small diameter antenna element:

I happen to use 2 inch diameter 30 foot long irrigation pipe "because I 
can" meaning I got a good deal on a bunch of it used.  The pipes have

4 way guying (much easier to tilt up than 3 way) and I have four
"umbrella wires" that are 21 feet long and are zip tied to the guy ropes
which go to ground anchors 30 feet out from the pipe.  This puts the
height of the umbrella wire tips at 15 feet.  The umbrella wires are
highly recommended to give additional gain.  But I strongly suspect
that they would also mitigate any issues with using small diameter
wire in place of 2" pipe.  If you only use the wire without the
umbrella wires, you can easily calculate the reduced capacitance
due to the small diameter using the usual formula.  Fortunately,
the function is logarithmic not proportional to diameter to length
ratio.  Voltage gain is basically proportional to antenna capacitance.

I have a 75 to 300 ohm transformer right at the feedpoint (made with
the usual binocular cores).  This gives me additional gain vs feeding
directly from 75 ohms.  It works against four 30 foot long radials on 
top of the ground.  I have found that this configuration gives

plenty of signal without any preamp besides the one built into the
radio.  I live only 6 miles from a 50 kW AM BCB station, so preamps
are a problem here.  The DX engineering preamp with the 8 foot CB
whip gets creamed by the BCB QRM, and there is no way to protect
it by inserting a BCB reject filter, AFAIK.

I put the combiner midway between the verticals and have a couple
of relays to select 0 or 180 degrees or omni.  I will strongly second
the other posters about NOT putting DC on the coax ("too clever
by half").  I happen to have a bunch of CAT5 cable on hand and use
that for the relay coil drive.  The "controller" in the shack is
just a few toggle switches.

A possible idea to explore is to use LATCHING relays at the antenna,
and then it is OK to run DC over the coax momentarily.  Amazingly,
I haven't heard of anyone trying this (including me).

For the connections from the antennas to the combiner and for the
coaxial delay line at the combiner, it is worth considering using
RG59 coax with a true copper center conductor.  Every sample
of RG6 with the copper plated center conductor varied considerably
from 75 ohms on top band and was frequency dependent.  It you
do use it for the delay line, measure its time delay at your
operating frequency.  Many delay measurement techniques rely on
measuring delay at some "convenient" frequency and assuming
it is "non-dispersive".  Wrong.

Anyway, this is what works for me; YMMV.

73
Rick N6RK
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Re: Topband: [RFI] Powerline noise question

[Richard (Rick) Karlquist]

I am going to start with the preamp kit DXE sells to go with the flag 
kit.  This particular noise source is extremely strong so I am 
optimistic that it will be sufficient.  I can add the preamp that

came with my Pixel loop if necessary.

Again, your recommendation means a lot.

73
Rick N6RK

On 12/30/2022 5:08 PM, Frank W3LPL wrote:

Rick,

You'll be very pleased with the performance of the WB8DSB RFI hunting
flag antenna.

Don't forget to need lots of preamp gain. The WB8DSB flag is about 60 dB
down from a dipole on 160 meters. 40 dB of preamp gain is needed until
you're very close to the RFI source.

73
Frank
W3LPL

- Original Message -
From: "Richard" 
To: "Frank W3LPL" , "rfi" , "PVRC" 
, "topband" 
Sent: Friday, December 30, 2022 8:25:47 PM
Subject: Re: [RFI] Powerline noise question

Thanks Frank.  You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

On 12/29/2022 7:53 PM, Frank W3LPL wrote:

Hi Rick,

I recently built a WB8DSB man portable flag antenna (March 2021 QST)
for RFI geolocation, its performance far exceeds my expectations.
Its narrow deep null quickly, easily and definitively located the
source of very troublesome 160 meter RFI to a single power pole
more than three miles from my QTH.  Prior to constructing the
flag antenna I could locate the RFI to only within a few hundred
yards of the RFI source.

I built my flag antenna entirely out of materials I had on hand
from previous projects including 3/8 inch diameter fiberglass rods,
a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
a case of eight AA batteries to provide power to the preamps,
a switchable attenuator and a Tecsun PL330 portable HF receiver.

I highly recommend this easily constructed RFI geolocation antenna
for the toolkit of any serious HF operator.

73
Frank
W3LPL





- Original Message -
From: "Richard" 
To: "rfi" 
Sent: Friday, December 30, 2022 3:15:32 AM
Subject: [RFI] Powerline noise question

I have a powerline noise coming from about 2 miles away, which is
nevertheless quite strong at my QTH.

Here are the symptoms:

1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.

2.  The noise goes away after a rain; then comes back after things dry
out.

3.  Can be heard from 500 kHz up to a few MHz.

4.  The noise is very strong along a road for a few miles.  There is a

power line that follows the road.  I haven't been able to localize it
better than

that so far.  From my QTH, though, it is definitely coming in at a
specific azimuth

which is consistent with the noisy road a few miles away.  (Using a loop
antenna

for DF'ing).

Any help appreciated.




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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: [RFI] Powerline noise question

[Richard (Rick) Karlquist]

Thanks Frank.  You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

On 12/29/2022 7:53 PM, Frank W3LPL wrote:

Hi Rick,

I recently built a WB8DSB man portable flag antenna (March 2021 QST)
for RFI geolocation, its performance far exceeds my expectations.
Its narrow deep null quickly, easily and definitively located the
source of very troublesome 160 meter RFI to a single power pole
more than three miles from my QTH.  Prior to constructing the
flag antenna I could locate the RFI to only within a few hundred
yards of the RFI source.

I built my flag antenna entirely out of materials I had on hand
from previous projects including 3/8 inch diameter fiberglass rods,
a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
a case of eight AA batteries to provide power to the preamps,
a switchable attenuator and a Tecsun PL330 portable HF receiver.

I highly recommend this easily constructed RFI geolocation antenna
for the toolkit of any serious HF operator.

73
Frank
W3LPL





- Original Message -
From: "Richard" 
To: "rfi" 
Sent: Friday, December 30, 2022 3:15:32 AM
Subject: [RFI] Powerline noise question

I have a powerline noise coming from about 2 miles away, which is
nevertheless quite strong at my QTH.

Here are the symptoms:

1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.

2.  The noise goes away after a rain; then comes back after things dry
out.

3.  Can be heard from 500 kHz up to a few MHz.

4.  The noise is very strong along a road for a few miles.  There is a

power line that follows the road.  I haven't been able to localize it
better than

that so far.  From my QTH, though, it is definitely coming in at a
specific azimuth

which is consistent with the noisy road a few miles away.  (Using a loop
antenna

for DF'ing).

Any help appreciated.


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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Topband: Noise investigation by FCC? (was: Re: ARRL 160)

[Richard (Rick) Karlquist]

On 12/7/2022 6:57 AM, Roger Kennedy wrote:


To update on my Noise problem . . . I have had OFCOM engineers here this
week trying to track it down. We came to the conclusion that I have TWO
separate noise sources, that are both about the same strength. They have



73 Roger G3YRO



Can anyone inform me at to whether there is any kind
of analogous help about noise on this side of the
pond from the FCC?  I have a severe noise source
audible for miles on my AM car radio.  It doesn't
sound like the familiar power line noise, but
rather appears to be CFE (Customer furnished equipment)
as opposed to anything related to the utility.  The
utility only furnishes the "antenna" AKA the power
lines.  (It follows a particular line for miles).
That line is few miles from me to the southwest,
as indicated by the null in the noise from my loop
antenna.

Thanks for any help.

Rick N6RK
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Re: Topband: ARRL 160 meter contest

[Richard (Rick) Karlquist]

Did I miss the part about WHERE TO SEND THE PHOTOS, etc?

Rick N6RK

On 12/2/2022 9:40 AM, TreeN6TR wrote:

This is a message from N5OT:

Greetings.  My job is to write up the 160 meter contest after the dust
settles for the ARRL.  The best writeups have lots of photos and personal
stories.  Please do what you can to remember the fun this weekend with
pictures and anecdotes.  Feel free to send me whatever you want.  Try to be
creative - one can only look at so many photos of an op sitting at their
radio.  Whatever you send, it will be much appreciated.

I'm always interested in hearing about the antennas people use to get on
160.  I keep saying I should do an article just on THAT.  Send me enough
interesting stuff on your crazy antennas and ... who knows!

Thanks in advance.  See you on the air in a bit.

73 - Mark N5OT
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Re: Topband: Top Band: Stew Perry Contest

[Richard (Rick) Karlquist]

I worked two JA's this morning near the end of the contest.
However, their signals were not very strong. One of them,
big gun JA5DQH, I had easily worked on phone last year.  But I would
say that the main problem with the fall edition of the
contest is simply limited activity.  By early in the evening,
I found that I couldn't get any response to my CQ's and
I could not find any S opportunities.

73
Rick N6RK

On 10/23/2022 10:24 AM, Roger Kennedy wrote:


Well the poor DX conditions on 160m seem to be persisting . . .

I had a listen on the band several times during last night . . . but didn't
hear a single DX station (although I did have quite a high noise level).

But I also didn't hear any of the few Europeans on the band working any DX
either.

Roger G3YRO



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Re: Topband: ARRLWWDX-SSB Contest 160m conditions

[Richard (Rick) Karlquist]

On 3/13/2022 2:33 PM, Roger Kennedy wrote:


Signals were still well down this weekend for the Spring Stew Perry, but
came on the band a couple of times during last night, and managed 28 NA


73 Roger G3YRO


In the Spring Stew, from the west coast USA, signals were excellent from 
the east coast and Asia.  I had no trouble working a number of JA's and
a VK (39 points!) running only 100 watts to a vertical.  As usual, we 
heard only thestateside end of many EU QSO's.  No openings to EU from here.


Rick N6RK
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Re: Topband: Series LC to notch AM broadcast ?

[Richard (Rick) Karlquist]

On 2/20/2022 9:41 AM, jim.thom jim.t...@telus.net wrote:

Has anybody tried using a simple series L-C to notch out ONE offending AM
broadcast station ?  I'm talking about wiring from hot side of coax...to



Jim   VE7RF
_


See:

MFJ-8504AN, AM Notch Filter

73
Rick N6RK
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Re: Topband: TV coax + F-connectors

[Richard (Rick) Karlquist]

On 2/20/2022 7:46 AM, Radio KH6O wrote:


Reading the comments about possible lack of uniform impedance and
other short-comings, I remind myself that I'm an amateur, not a
professional. A few milliwatts loss doesn't concern me.



73, Jeff KH6O
_


The issue of non-uniform impedance and VF vs frequency is not one
of "amateur vs professional", but rather simple antennas vs phased
arrays.  Junky coax can noticeably mess up the array pattern.

73
Rick N6RK


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Re: Topband: F connector how-to video

[Richard (Rick) Karlquist]

On 2/4/2022 8:58 AM, VE6WZ_Steve wrote:


When you find a cable that you like, stick with it!


Before falling in love with a cable, it is worthwhile to check its 
impedance accuracy vs frequency and its low frequency loss and the 
consistency of its velocity factor.  Once you do this, you will never 
again buy cable from the big box stores, no matter how easy it is to put 
on F connectors.


73
Rick N6RK
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Re: Topband: F connector how-to video

[Richard (Rick) Karlquist]

On 2/3/2022 7:29 PM, VE6WZ_Steve wrote:

“Why the “F” won’t it go on ?”
https://youtu.be/pE04tDpdhRA 
73, de steve ve6wz
_


YMMV, but what I do is actually use the conical spreading tool you show 
on the video (that you say doesn't work) and it works perfectly for me 
every time.  I only use Belden connectors, like the ones you show but
don't use.  I prefer the yellow Palladin stripper and the Platinum Tools 
Copper Clad Steel Coax Cutters available at Tech Tool Supply.


You are correct that heat is magic for making them go on
easily.  Same as putting hoses on hose barbs (or removing them).  For
hoses I use boiling water.

73
Rick N6RK
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Re: Topband: Square "loop" antenna for 160

[Richard (Rick) Karlquist]

On 1/31/2022 6:22 PM, Radio KH6O wrote>

I have to live with CC homeowner restrictions. I plan to erect a disguise
wire antenna around the perimeter of my roof; total length will be about
190 feet. Elevation will be about 20 feet above ground and will be fed with
150 ohm twin lead.*

My question is: Should this be a continuous loop or should the point
opposed the feedline be terminated with an insulator, thus giving two

Jeff KH6O
Naval Air Staiton Point Mugu, CA


Warning, long posting.  Sorry for the BW.

It just so happens that I have a horizontal square loop antenna made of 
#18 insulated wire, that has a perimeter (AKA length) of 200 feet, and 
an adjustable height of zero to 30 feet, and is in the clear, away from 
buildings, etc.  It has a drive impedance of about 5 ohms + j600, IOW a 
Q of about 100, and therefore a bandwidth of a dozen or two kHz.  At 30 
feet, it consistently has a gain of -30 dB vs my 90 foot top loaded 
vertical over a massive ground screen on high conductivity ground. 
Except for certain stations within a few hundred miles where the loop 
might be "only" 20 dB down from the vertical, due to NVIS or short skip, 
or something.  Reducing the height to 20 feet only affects the gain by a 
few dB.


IMPORTANT!  The size of this loop is too large for it to be "magnetic" 
with constant current.  However, I use a trick to make the current 
constant.  Without that, the loop would be even worse.


Now to your questions:

Not closing the loop creates a bent dipole.  It is approaching a half 
wave, but will still need loading coils.  I don't know how loading coils 
are going to qualify as "stealth".  I live on 20 acres so I don't think 
about stealth.  I will say that I have also erected full size 160 meter 
dipoles at a height of 30 feet.  Your bent dipole at 20 feet would be 
worse than this of course.  My dipoles had a fairly narrow bandwidth, 
maybe a few dozen kHz.  I don't remember for sure, but the gain was 
perhaps 6 dB higher than the loop, but don't quite me.  Running the 
legal limit power, you will be lucky to get a watt or two EIRP.  The 
digital modes like FT8 will be your only viable option.


If you don't have an amplifier, you need to get a cheap used tube type 
one.  They don't command much money these days.


Puh-leeze! don't feed it with twin lead.  You need a remote matching 
network at the feed point.  Hopefully with some frequency switching so 
you can cover more than a sliver of the band.  The question about 
stealth is again raised.


BTW, I only use my loop for receiving.  I worked a JA while using it for 
receive when it was lowered to 10 feet.  It generally receives as well 
as the vertical in terms of signal to noise ratio, with the loop at its 
usual 30 foot height.


73
Rick N6RK


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Re: Topband: Re CQ WW 160m Contest

[Richard (Rick) Karlquist]

On 1/31/2022 5:50 AM, Steve London wrote:

Ron,

I'm surprised you didn't have a better USA opening. From here in New
Mexico, we had an outstanding Pacific opening on Saturday from 1215Z-1415Z.
Many JA, but also:



Same here.  In a 40 minute period starting at 1240Z, I worked 40 JA's 
plus S Korea and UA0.  All of them called me, while I was running.

Even JA3YBK.   Three Chinese stations were heard but not
worked ... by anyone.  Hi.  I ultimately put 47 JA's in the log that
morning.  Oh, did I mention I was only running 100 watts?

Rick N6RK
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Re: Topband: 1:2 UNUN

[Richard (Rick) Karlquist]

Maybe this will help:

I use a 1:2.25 Unun (3 to 2 turns ratio).  It will match 22.2 ohms
to 50 ohms.  It is wound on a single 2.4 inch diameter core of 77
material.  A pair of RG-58 coax cables are wound around it in
tandem.  I put on as many turns as would fit ... about 10 turns.
The shields of the two coax cables are wired in parallel.

This results in essentially a trifilar winding (1.  The shields;
2.  One of the center conductors  3. The other center conductor)
This trifilar winding can then be connected in the usual way to
get a 3 to 2 turns ratio autotransformer).  The order of the
connections is:  center conductor #1, then the shields, then
the #2 center conductor, in series.  The radio drives
the 3 windings in series, and the antenna is tapped down to
utilize only 2 of them.  I run this at 1,500 watts in
contests with no problems at all.

The concept is extensible to a quadfilar winding constructed
from 3 coax cables in tandem (shields in parallel).  This can
be wired with a 4 to 3 turns ratio resulting in a 1:1.77 UNUN.
This matches 28.125 ohms to 50 ohms.  An alternate modality
I have used is to use two coax cables as in the 1:2.25 UNUN,
but make one of the coax cables from tri-ax.

I can highly recommend UNUN's for the convenience factor if
your drive impedance is compatible with the available ratios.
They are broadband, no tuning.

73
Rick N6RK

On 1/17/2022 6:18 AM, Kenny Silverman wrote:

Does anyone have a drawing on how to wind a 1500w 1:2 UNUN?  And what type of 
core is needed?

This is for my 160m vertical which is about 28 ohms.

Regards , Kenny K2KW
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Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/10/2022 1:13 PM, Jim Brown wrote:
As usual, I agree with Rick.  But I'd like to observe that an extensive 
study of loaded mobile whips published in two parts in QEX about ten 
years ago showed that inductive loading, especially at the base, was a 



73, Jim K9YC



I wasn't clear.  I assumed that the vertical has top loading wires, and
the base loading inductor is added to get resonance.  According to W8JI,
once you have enough top loading to get uniform current in the vertical, 
then it is OK to have a base mounted tuning inductor.  For short 
verticals, making the top wires extremely long to achieve resonance 
without a loading coil is sub optimal because it reduces the radiation 
resistance too much.  I once resonated a 60 foot vertical on 160 meters 
using two 100 foot top umbrella wires, because it was a temporary 
antenna and I didn't want to fool with a loading coil.  The drive 
impedance was very low.


73
Rick N6RK
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Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/10/2022 10:42 AM, Kenny Silverman wrote:

N6BT’s ring is pretty flexible in its dimensions. It can be 3 or 4 sides (or 
anywhere in between) and can handle some variation in symmetry.

I’ve been having issues finding a solution to the high tree attenuation on my 
property and I had an inverted L with the ring and another inverted L 340’ away 
with 60 x 100’ radials.  The model showed there was some interaction between 
the 2 antennas so exact difference was not known. But basically the ring was 
very close to the 60 radial version.

One of the key issues is making sure the inverted L section is close to 
resonance. If it’s short, more current is moved into the ring which is not 
desirable.

Regards , Kenny K2KW
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Actually, you are kidding yourself making the inverted L long enough to 
be resonant.  That has the effect of moving more current into the 
horizontal part of the inverted L, which is also not desirable.  The 
solution to this dilemma is to use a top loaded (T type) vertical, and a 
loading coil if necessary.  The resonant inverted L is "elegant" but not 
optimal.


Rick N6RK
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Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/9/2022 8:22 AM, Richard (Rick) Karlquist wrote:



electric fence wire works perfectly for elevated radials  Also consider 
N6BT's single spiral radial configuration as an alternative to FCP.


Rick N6RK
_


See:

https://nextgenerationantennas.com/presentations-1

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Radials on ground v FCP

[Richard (Rick) Karlquist]

On 1/9/2022 4:51 AM, CUTTER DAVID via Topband wrote:

Hi Rob

I see copper prices have doubled in the last year.

My intention is to compare and contrast the cost and performance of short 
verticals over a large field of ground radials v the very modest amount of wire 
required for the FCP.  In Guy's article



This is a false dichotomy between FCP and a broadcast station ground 
screen.  The best use of wire is to have a small number of elevated 
tuned radials with proper RF choking.  As shown by N6LF, you can do well 
with just 8 radials, about 100 feet long each.  On 160 meters, they 
should be 20 feet high for optimum performance.  BTW, cheap aluminum 
electric fence wire works perfectly for elevated radials  Also consider 
N6BT's single spiral radial configuration as an alternative to FCP.


Rick N6RK
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Re: Topband: Magnetic Loop Height Question

[Richard (Rick) Karlquist]

On 10/25/2021 8:32 AM, W7TMT - Patrick wrote:

I'm looking to improve my receive situation on 160. Given the numerous 
limitations to my location it appears my best chance of seeing any improvement 
might be a small loop. All of the designs specify a minimum height of above 
ground. The DXE version suggests 5 foot as a minimum and other designs are 
similar. Any thoughts on what that number would be if we are talking about 
super conductive ground below it, in this case saltwater? Any other 
considerations with a loop over seawater?

Thanks for your time.

73, Patrick, W7TMT


Hi Patrick:  You had a great signal during the recent Stew Perry;
love that salt water.

Since you asked about loops, I will plug mine:

http://n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf

All this loop (or any other one) does is allow you to null out
a single noise source.  If your noise problem is such that
you have a dominant noise source, they can be useful.

I don't know where you got that there is a minimum
height above ground.  W3LPL actually says NOT to raise
up the loop, for complicated reasons I won't go into here.
I don't even think being over salt water matters.  A loop
is basically a phased pair of verticals; verticals love
salt water.

For receiving, the trouble with salt water is similar to
the trouble with my high conductivity clay:  it propagates
all local noise VERY well.  What has worked here is to
put up a low dipole to reject some of the vertically
polarized noise.  Maybe two (choose one) of them at right angles.
They do unfortunately receive vertical noise off the
ends.

BTW, a Beverage is a non-starter over salt water, as
is well known.

Another thing that helps is having a good SDR like my
Flex 6700 with very narrow (down to 50 Hz) non ringing
CW filtering.

Hope to work you again in the big Stew!

73
Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Topband: Laser distance meters

[Richard (Rick) Karlquist]

I am considering replacing my 100 meter tape measures with
a Bosch GLM400CL laser distance meter to use for laying out
my next 160 meter circular array.  I am wondering if anyone
has any experience with this model or any other models that
work to a range of 100 meters.  (That spec eliminates the vast
majority of meters).  How important are accessories like
tripods and target cards?

73
Rick N6RK
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Re: Topband: Vertical Dipoles on 160 Meters

[Richard (Rick) Karlquist]

On 5/7/2021 10:31 AM, John Crovelli wrote:
For those who have limited space and are unable to lay out an 
effective ground system, the vertical dipole offers a very worthwhile 
alternative to an Inverted-L or low Inverted-V.


I think of this as essentially an inverted-L with one elevated
radial ... driven at the second harmonic.  It seems to me it
would work work better with 2 or 4 radials, and with 2 or 4
top loading wires.  And it can be driven with a common mode
choke at the bottom of the vertical section.

Rick N6RK
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Re: Topband: Aluminum fence wire for Beverage

[Richard (Rick) Karlquist]

On 4/13/2021 9:04 AM, Peter Krulewitch wrote:

I tried the wire with some success but sag due to stretching created a problem. 
Wonder what your experience is and also use of steel fence wire.
W2LL

Sent from my iPhone
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Did you use the tensioning springs at the ends that are
made for electric fences?  I had beverages up for years
with these springs and never had a problem with sagging,
even with supports spaced every 200 feet .

73
Rick N6RK
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Re: Topband: 43’ 80 Meter Vertical

[Richard (Rick) Karlquist]

On 4/10/2021 1:16 PM, Chortek, Robert L. wrote:

Hoping to get some guidance from the antenna gurus here.


Can someone tell me if I added two top hat wires 16 GA THHN sloping at 45 
degrees “about” how long they would need to be to resonate at 3.545 MHZ.

Bob/AA6VB
Robert L. Chortek


After SWR, the most overrated goal for ham radio antennas is
resonance.  You should use the amount of top loading that
maximizes the radiation resistance.  Then put an appropriate
reactance in series with the antenna to provide a resistive
load to the transmitter at 3545.  The reactance may be turn out
to be inductive or capacitive.  You will also want to make
the series reactance variable somehow unless you only ever want to 
operate on 3545.


You would also be advised to use 4 top loading wires instead of
just two.  There is a substantial advantage for 4 vs 2.  Beyond
4 top wires (say 8) the benefits aren't worth the trouble.
This is explained by the fact that 4 is the maximum number of
top wires that don't couple to each other.

It is also advantageous to pull out the top loading wires to
a more gentle slope if you can.

You can use bare aluminum electric fence wire to reduce weight
and wind loading on the vertical.


73
Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Adding 80 m to 160 m quarterwave vertical

[Richard (Rick) Karlquist]

On 4/5/2021 8:48 PM, Lloyd - N9LB wrote:

Why not remove the 80m wire and simply run the entire 30m tall mast (with 
additional top hat) on 80m as a half-wave vertical?
A "legal Limit" antenna tuner should handle it, or build your own 80m antenna 
matching unit.



I did exactly what you describe with my 27m (90 ft) mast.
It apparently worked fine (I didn't have another antenna
to compare it to.)  I built a homebrew tuner.
I don't know of a commercial one that could handle the
high voltages.  I later decided this was too much
trouble and installed a relay at the 60 foot level that
allowed it to run as a conventional vertical on 80 when
the relay was open.

73
Rick N6RK
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Re: Topband: 160 meter 1/8 wave

[Richard (Rick) Karlquist]

On 4/1/2021 1:48 PM, Dave Cuthbert wrote:

Hi Doug, for now I will assume you mean an inverted-L with apex at 1/8
wavelength. Let's see what EZNEC shows for a top hat vertical at the
extreme against the inverted-vee. We can refine the model with more input
from you such as take-off-angle, top hat design and ground parameters. From
that a practical loading coil is added either at the bottom or at the top.

1.8MHz
*65' vertical* with top hat sized for a nearly square current distribution
6 x 20' top hat
Loading coil not required, antenna is resonant at 1.8MHz
32 x 130' radials plus 5 ohm GND loss added to try to account for NEC-2
0.005S/13 GND, "average"
Gain at a 10 deg take-off angle =* -2.5 dBi*

1.8MHz
Inverted-V apex at 65' with ends 10' above GND
0.005s/13 GND, "average"
Broadside gain at a 10 deg take-off angle = *-10.5 dBi*

  dave KH6AQ



The original poster asked about an inverted-L and you simulated
an inverted-V.

When doing these simulations, it is extremely important to use
the "Desc Options" menu in EZNEC and select "Vert Horiz" as
opposed to the default which is "total".  Vertical is the "money"
polarization on 160, in most cases.

FWIW, I had to operate in a 160 meter contest once with a 60
foot top loaded vertical.  It had two very long top loading wires
that sloped down to the ground and I pruned them for resonance at
1830.  The bandwidth was much narrower than my usual 90 foot
vertical, which was already fairly narrow (this is actually GOOD). 
Anyway, it worked great in the contest (subjective opinion) although

I couldn't A/B it with the 90 foot vertical.

My feeling was that the 60 ft vertical probably got out nearly
as well as the 90 ft vertical, but the very narrow bandwidth would
have required a suitable antenna tuner for effective on the air
use.  Any 60 ft vertical that does NOT have very narrow BW is probably 
not very efficient at least when it comes to vertical polarization.


73
Rick N6RK
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Re: Topband: Elementary Inverted L questions

[Richard (Rick) Karlquist]

On 3/25/2021 11:39 AM, N4ZR wrote:
Thanks to everyone who has replied so far, and apologies - I did a lousy 
job of describing the antenna.  First off - I set out to make it 1/4 
wave (approximately 128 feet) long, and the starting length of wire 
(what I actually put up) was 140 feet.   Vertical portion is about 55 
feet, and the horizontal part is more or less level. The feedpoint choke 


Guess about your motives:  I am thinking you want to make the inv-L
long enough to be resonant.  Seems elegant, but actually, this is an
invalid paradigm.  You would be far better off building a top loaded
vertical, even if the top loading wires aren't completely horizontal.
Then use a grounded loading coil at the base with two adjustable taps, 
one for loading and one for tuning.  Very popular; works every time.

(W8JI commented that, with any significant top loading, the current
in the vertical portion is uniform thus bottom loading is as good as
center or top loading).

73
Rick N6RK
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Re: Topband: Antenna thoughts

[Richard (Rick) Karlquist]

On 3/2/2021 11:19 AM, 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



When doing these comparisons on 160 meters, it is crucial
to use the EZNEC "Desc Options" setting (2nd from the bottom
in the main window) to plot vertical and horizontal
radiation separately.  Then count only vertical
polarized radiation as the "money spec" (as
we used to say at Agilent :-).  If you use combined
polarizations, it is very easy to be fooled into
thinking that an inverted L with a very long top has fantastic
efficiency, vs a T vertical.  Well, I will grant you
that it is very efficient at warming the clouds.

73
Rick N6RK

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Re: Topband: Broad band antenna approach for 160 Contesting

[Richard (Rick) Karlquist]

On 2/28/2021 7:40 AM, Grant Saviers wrote:
The nice thing about switched serial caps (if same values) for tuning 
upwards from a low resonance is the voltages are all the same. Plus caps 
and appropriate relays are cheap, easy, and small.


Rick, I think you might have suggested this to me, and my implementation 
was published in QEX May/June 2019.


Grant KZ1W



Grant, Dave etc:

I hadn't seen this article: the DVD was still shrink wrapped :-)
Anyway, nice write up, it's similar to what I did, so maybe
I suggested it.  A couple of discussion points (not criticisms):

1.  I use binary weighted cap values.  In the article you say
you going to do that but a comment on this reflector changed
your mind to equal values.  You mention in your posting today
that this is nice because all the voltages are the same.  Is
there any other reason for this decision?  The advantage of
the binary weighting of course is that only two caps and only
two relays are needed for four segments (or 3 and 3 for 8 segments).

2.  Figure 7 shows 6 relays to get "all decodes"? Perhaps this
got messed up in Newington.  Can you explain it better?

3.  Figure 8 shows your 50 ohm t0 25 ohm matching transformer.
The text credits K9YC and then goes on to say it is a transformer,
a balun, and a common mode choke, all in one.  I know K9YC
very well and he correctly rails against the misapplication of the
word "balun".   Maybe more QRM from Newington?

Anyway, if you were going from 50 ohms to 12.5 ohms, this loose
talk could almost be true.  But AFAIK, going from 50 ohms to
22.2 ohms (3:2 turns ratio) is simply an unun, which is an
autotransformer.  At least that's what I'm doing.  It could
never be confused with a transformer, balun or common mode choke.

4.  I like the Schrack relays.  I see that DigiKey still has
these available, but they identify them as "TE Connectivity
Potter & Brumfield" but they also say "Series RZ, SCHRACK."
I may use those going forward in place of the ones I
used before.  You mentioned the CDE mica caps I used,
and then said you used cheap Ukrainian ones.  Do
you by any chance have a pointer to them on ebay?  I realize
that 4 years is a long time in ebay years, so maybe not.

BTW, an additional advantage of using capacitors instead of
a tapped inductor is that the inductor will lose a lot of Q
if a metal enclosure is used, unless it is huge.  A plastic
enclosure is clumsy and self destructs in sunlight.

Finally:  have you gotten a lot of response to the article,
especially in terms of people actually building it?
Maybe I need to jump on the frequency agility bandwagon,
if there is a critical mass of other stations to work
who are on board.

Keep the good ideas coming guys!

73
Rick N6RK
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Re: Topband: Broad band antenna approach for 160 Contesting

[Richard (Rick) Karlquist]

On 2/27/2021 2:23 PM, Artek Manuals wrote:

Rick et all


he feed, The taps are relay selected .  Taps selected for a dip
at 1816, 1840 , 1860, 1880, 1900 and 1920. SWR 1.3:1 from 1.8 to 19.5 
which the my KPA1500 and Alpha 9500 both love.


Dave
NR1DX
manu...@artekmanuals.com



Thanks for posting this suggestion.  Perfectly reasonable design.
I use an alternative design using switched mica capacitors.
I also use a 2.25:1 matching transformer, but the "windings"
are implemented using coax.  Not sure if Sevick does this.

73
Rick N6RK
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Re: Topband: CQ ssb contest

[Richard (Rick) Karlquist]

On 2/27/2021 11:01 AM, Tree wrote:

My general comments about the contest.

Back about 15 years ago - it seemed like there was plenty of activity above
1900.  AA1K spent most of the contest in 1999 kHz.  Maybe it was conditions
- but it seemed to be a lot less going on this year above 1.9 MHz.  I had


I thought about retuning my TX vertical somewhat higher temporarily
just for this contest, but I was thinking that many stations would not
have the capability to go above 1.9 MHz, so CQ'ing up there would have
limited success.  Without changing from my "normal" CW setting, I can
get away with going up to almost 1.9 MHz before the Alpha 9500 complains
too much.

What is really needed is a remote switched tuning network that would
divide the band into eight 25 kHz segments.  Then I could S the high
frequency stations on a demand basis.  It is on my "someday" list of
things to build.  I already have built one for 80/75 meters with 8
segments, so the design is in my head.


Rick N6RK
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Re: Topband: JA on 160m SSB

[Richard (Rick) Karlquist]

On 2/25/2021 10:14 AM, Saulius Zalnerauskas wrote:

Hi,

Just interesting how many of You worked JA's on SSB?
Me never. Best time I know, but what frequency they prefer?
Maybe it will happen this weekend during contest?
Sam LY5W
_



Just worked JA7BXS at 0906Z and JA5FDJ at 0907Z
on a frequency of 1850 kHz.  I continued to CQ
until 0930Z, but no other JA's were heard.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: FW: The WD8DSB mini-flag antenna (LONG!)

[Richard (Rick) Karlquist]

On 2/26/2021 7:31 AM, John Kaufmann via Topband wrote:

I think there may be some semantic confusion over the term "averaging" and
how averaging affects noise when making spectral measurements, so let me
clarify what I mean.  My comments are specific to the P3 but are fairly


Averaging is a nice technique that mitigates the poor sensitivity
of the mini-flag, but only for "bright lines" due to power
supplies, etc.  I would be surprised if it would do anything
to improve DF'ing power line noise, which is clearly a major
application domain.

73
Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: The WD8DSB mini-flag antenna

[Richard (Rick) Karlquist]

Correction to my previous comment.

I didn't realize that the mini-flag
impedance is close to 50 ohms resistive
at all frequencies of interest.
Therefore, the 50 NF of any amplifier
is also the NF that applies when connected
to the loop.

The 50 ohm source impedance is a due to a physical
resistor with a physical temperature of 300K, therefore
the noise temperature of the system will never be less
than 300K.  It is easy to find an amplifier that gives
a sensitivity within a few dB of a hypothetical
noiseless amplifier.

Rick N6RK

On 2/24/2021 4:53 PM, Richard (Rick) Karlquist wrote:



> 6.  NF is source impedance dependent.  Measuring the NF with
a 50 ohm source doesn't tell you anything about the effective
NF when terminated with the loop impedance (which is no where
near 50 ohms resistive.)


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Re: Topband: The WD8DSB mini-flag antenna

[Richard (Rick) Karlquist]

On 2/24/2021 12:26 PM, n...@comcast.net wrote:

Hi Rich

" The problem here is that any loop antenna inherently has a noise
temperature of 300K, because it is lossy, and because it "sees"
the earth"

Would you elaborate on that? Small loop 1/10 of wave length works very
different from a loop or large loop. I experimented with a large number of



Local noise is the most misunderstood figure. On top-band during a winter
Sunday morning the noise can be low as 70K. On topband the only source of
nom mam made  noise atmospheric noise. No atmospheric activity means no
noise. Yes it is that low.  I am using horizontal phased loops for almost 15


1.  I am specifically talking about "small" loops.

2.  In small loops, the ohmic dissipation of the conductor
vastly overwhelms the tiny radiation resistance.

3.  This is unlike a vertical antenna or a dipole, which can
be considered non-dissipative.

4.  Therefore, if the conductor is at a physical temperature
of 300K, its Johnson noise will correspond to that temperature.
(-173 dBm/Hz).  IOW, the antenna's noise temperature will never
be less than 300K.

5.  If we were to put a loop in "free space", meaning outer space,
where there is no noise besides the 3K cosmic background noise,
it would still have a noise temperature of 300K, assuming that
the physical temperature were somehow maintained at 300K.

6.  NF is source impedance dependent.  Measuring the NF with
a 50 ohm source doesn't tell you anything about the effective
NF when terminated with the loop impedance (which is no where
near 50 ohms resistive.)


still in use here, using 6 BF981 and  large Q input filter. It measured .7
db NF including the input tuning filter loss.  It does make a difference on
signals at noise level. I built one for NX4D and Doug still use it.  Making


7. It is extremely easy to get a 50 ohm NF of 0.5 dB with a BF981
at 88 MHz as specified by its data sheet.  All you have to do
is transform the 50 ohm source so that it loads the FET with
about 1,000 ohms.  I did this 40 years ago.  Unfortunately,
at 1.8 MHz, the flicker noise of the BF981 dominates, so you can't
get the low NF down there.

8. I did this same experiment with the multiple paralleled BF981's over 
15 years ago and was limited by flicker noise, which is

unspecified, YMMV.  Maybe you had better devices than I did.


pair of phase loops. A/B tests with NORTON preamps show not possible to copy
the weak signals I did copy with my 6xBF981.


Norton amps are not noted for low NF, so this is a straw man.
Maybe they are picking up BCB QRM (see below).


Implementation is a different ball game. The .7 db NF preamp needs 3 level
of shield including a magnetic shield with steel, just aluminum is not
enough, and no open shield at all, a 1 mm gap will ruin your system. You can
find information about my preamp on google or WWROF archives.


Considering that the input of the preamp is deliberately connected to 
the antenna, it is hard to imagine what signal the shield is

shielding the amplifier from.  Large BCB signals out of band
coming up the feedline?  Is the shield still needed for QTHs that have
no nearby BCB stations?



73's
N4IS
JC



73
Rick N6RK
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Re: Topband: The WD8DSB mini-flag antenna

[Richard (Rick) Karlquist]

On 2/24/2021 6:32 AM, GEORGE WALLNER wrote:

Don,
I put that note out because friends were asking if with a 
"ultra-low-noise" pre-amp they could use it for DX. Unfortunately, 
that's not the case. (I have tried.)

George,
AA7JV/C6AGU



The problem here is that any loop antenna inherently has a noise
temperature of 300K, because it is lossy, and because it "sees"
the earth.  Therefore, a 0.5 dB NF amplifier adds 0.5 dB of noise,
etc.  As opposed to the 0.5 dB NF amplifier on an EME array that
is something like 10 dB better than a 3 dB NF amplifier because
of how noise temperature works.  Also, for NF's below 3 dB or so,
the source impedance is very critical in order to actually
achieve the specified NF.  This is impossible in an untuned
wide band loop antenna.  So in practice, a NF of around 3 dB
is the best you can do, and even that may be optimistic.

BTW, the multiple turns on the loop do not increase the available
received power or SNR in any way.  They simply increase the source
impedance.  It is analogous to a folded dipole.

There are two tools that will reliably increase sensitivity:

1.  Make the loop area larger.

2.  Change to a tuned loop.

73
Rick N6RK
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Re: Topband: The WD8DSB mini-flag antenna

[Richard (Rick) Karlquist]

On 2/23/2021 6:18 PM, David Raymond wrote:
Don. . .thank you for the very nice loop  article in QST.  And, thank 


something portable to home in on it.  Do you or anyone here  any 
suggestions for a reasonably good portable receiver with an external 
antenna jack (might be hard to find?) that will cover the 160m band . . 
.and maybe up to 30 MHz?


Thanks and 73. . . Dave, W0FLS



Not hard to find:  Icom IC-R6 hand held "scanning receiver",
100 kHz to 1.3 GHz, available at HRO.  I've been using one
of these for years for doing DF,ing.  Works great with a
hand held 144/432 MHz ham satellite Yagi.

Rick N6RK
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Re: Topband: The WD8DSB mini-flag antenna

[Richard (Rick) Karlquist]

For finding 160 meter noise sources, I use a C-Crane or Sangean
pocket AM band radio tuned to 1710 kHz.  It also has a very sharp
null due to the ferrite loop stick antenna built in.  The QST
antenna does have the advantage of being unidirectional, but I
can often triangulate with the pocket radio by walking around
and getting two different null directions.

Rick N6RK

On 2/23/2021 10:25 AM, John Kaufmann via Topband wrote:

Some of you may have seen the article by WD8DSB in the latest issue of QST.
I believe WD8DSB is on this reflector.  His article describes a mini-flag
antenna that can be used for direction-finding.  The neat thing about this
antenna, besides its compact size, is that it is unidirectional and is very
broadband.  It works from the AM BCB through 10m.  It produces a sharp null
off the back which allows you to determine signal direction without the
direction ambiguity you get with a conventional unterminated loop.

  


DX Engineering is producing this antenna as a kit, along with a companion
preamp.  (Disclaimer:  I have no affiliation or commercial interest in DX
Engineering).  See:  https://www.dxengineering.com/parts/dxe-noiseloop.  I
just bought the flag kit last week and finished assembling it this past
weekend.  I see today that the kit is now back-ordered until April so it was
good that I ordered it as soon as I saw the QST article.

  


It took me about 3 hours to assemble the mini-flag even though the DXE Web
site says it can be done in 1-2 hours.  There is a bit of fussy mechanical
assembly involved in getting the symmetry and dimensions just right,
although it's not hard work.  The flag is 42 inches wide and 21 inches tall.
The DXE version of the antenna has slightly smaller dimensions than those
given in the QST article, which results in a small reduction in gain, which
doesn't really matter, but the pattern is the same.

  


I did some testing of the mini-flag in the AM BCB.  The gain is very
low--about -65 dBi on 160m--so it needs a good preamp.  I used a homebrew
preamp made up of a couple of MMIC's that produce about 35 dB of gain.  The
DXE preamp for this antenna won't be available until April.  On the higher
frequencies, less preamp gain is needed because the gain of the mini-flag
increases with frequency.

  


My initial tests indicate this antenna clearly works.  By rotating the flag
for the deepest null, I could nail the heading an AM BCB station to a few
degrees.

  


This antenna could also be used as directional receiving antenna on its own.
Although it is not hugely directive, it can be rotated easily to peak or
null signals or noise, and it is better than a conventional unterminated
loop.  It has essentially the same RDF as other larger flag or pennant
antennas but is obviously far more compact.

  


This is a nice contribution by WD8DSB.  Now I have to go off with the
mini-flag and chase some local noise sources that have been plaguing me this
winter on the low bands.

  


73, John W1FV

  


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Re: Topband: ARRL CW Contest

[Richard (Rick) Karlquist]

No EU prop to CA at all.  I saw G3YRO spotted but heard
nothing on my new 9 circle RX array.

OTOH, I worked over 30 JA's between 0900Z and 1030Z.
A fair number were reporting only 100 watts.
Also worked ZM4T.

I supposedly QSO'ed UZ3DD with the 9 circle
beaming to Asia.  I see that UZ3DD is reported
as valid by SCP, but in not shown on QRZ.  WFWL?

Rick N6RK

On 2/22/2021 8:16 AM, wa8...@wa8wzg.net wrote:
No Propagation here in AZ either night,,I could hear East Coast stations 
working EU.. BUT could NOT here anything out here..

Even JA's were VERY slim and weak both mornings..
Still FUN!!
Tom
N7GP
Ex WA8WZG




On 2021-02-22 15:58, Roger Kennedy wrote:
Yes, most contacts were on the East Coast . . . farthest West was 
Oklahoma .

. . also worked into Georgia and Florida.

But didn't even hear any of the big signals I regularly work in Texas,
Colorado, Arizona etc.

It makes me wonder how many QSOs I would have had if the band had been 
open

further west !

Roger G3YRO



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Re: Topband: The Magic-T

[Richard (Rick) Karlquist]

The 90 degree hybrid is a third type of hybrid combiner,
distinct from the 0 degree and 180 degree types.  It
is typically used for 4 square phasing.  All 3 combiners
basically have a 3 dB insertion loss for signals having
appropriate phase conditions.

What you say is true to the extent that using a 90
degree combiner for two signals that are in phase
will result in a 3 dB loss.  You would not normally
want to do that.

Rick N6RK



On 2/10/2021 2:25 PM, P H via Topband wrote:

My impression is that a hybrid combiner, which introduces 90 degree shift 
(hence two identical signals of amplitude A fed to its inputs will give in 
total a signal with the amplitude of 1.41*A) is 3dB less efficient in 
comparison to a simple combiner where A+A gives 2*A at the output.
Do you have any thoughts on this?
A loss of 3 dB may be like "to be or not to be" of a QSO on 160 meters.
Regards
Piotr, SP2BPD
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Topband: The "Magic-T" vs 0 degree and 180 degree hybrid combiner/splitters

[Richard (Rick) Karlquist]

Ham radio literature often IMHO misuses the term
"magic tee" to refer to a transformer-based
0 degree hybrid combiner/splitter.

AFAIK, a magic tee is a WAVEGUIDE device as explained here:

https://www.tutorialspoint.com/microwave_engineering/microwave_engineering_eh_plane_tee.htm

and here:

https://blog.pasternack.com/uncategorized/magic-tee-magical/?gclid=Cj0KCQiApY6BBhCsARIsAOI_GjZHPm6HGT9O06rgnjXBXyc_xUD1aezOCcrNMuSrA4yrSjWqE-r3uFcaAotvEALw_wcB

In some loose sense, what hams talk about as a magic tee
is a lumped element equivalent of the waveguide magic tee.
Outside of ham radio, it is referred to simply as a 0 degree
hybrid.

The 0 degree hybrid circuit has a dual version called a 180 degree 
hybrid combiner/splitter that seems to be less well-known in ham

circles.  It is also a sort of lumped element equivalent
of the magic tee, as explained here:

https://electronics.stackexchange.com/questions/483616/what-does-the-25-%CE%A9-termination-resistor-do-in-a-0-180-degree-hybrid-power-splitt

The 180 degree hybrid has several advantages over the 0 degree hybrid:

1.  The input vs output impedance level is a function of
the turns ratio and therefore is not confined to a value
of 1:2.

2.  It happens to provide so-called "Galvanic Isolation" which
is sometimes helpful

3.  It inherently provides a 180 degree phase shift.

I often see 8 circle phasing networks that use a 3 piece
ensemble of separate magnetic parts, consisting of:

1.  A 1:1 transformer wired for a 180 degree phase shift
2.  A 0 degree hybrid ("magic-tee"), and
3.  A 37.5 ohm to 75 ohm transformer.

A single 180 degree hybrid replaces all 3 of the above.
(There is nothing "incorrect" about the 3 piece ensemble;
it's just needlessly complicated).

My 9 circle array uses this very successfully.

73
Rick N6RK
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Re: Topband: 160 Receiving Loops source?

[Richard (Rick) Karlquist]

On 2/4/2021 11:27 AM, Eric Rosenberg wrote:
With my antenna supports gone and living on a small city lot 
(Washington, DC), I'd like to try an 80/160 loop.


I have some physical limitations that make mechanical skills mediocre at 
best for building one, and am looking for an affordable source for a 
built one.





Thanks & 73,
Eric W3DQ
_



Here is a loop design I published over 11 years ago:

http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf

This is a loop that is remotely tunable from below 160 meters
to above 75 meters, and it has a loop with a 20 foot perimeter.
This gives you plenty of signal so that no preamp (other than
the one in your radio) is necessary.  There was a group in India
building these a few years back, but I don't know the current status of
that effort. The contact person was Prasad VU2PTT (vu2...@gmail.com).

For marketing reasons, commercially available loops are:

1.  Untuned
2.  Cover 0.5 to 30 MHz
3.  Have a circumference of 10 feet
and
4.  Use a preamp

The need for the preamp drives up the cost considerably.
I purchased a Pixel loop like this to compare it to my design.
It turns out that the signal out of the 10 ft untuned loop is
so low on 160 meters that the sensitivity is limited by the
noise figure of the preamp, unlike my tuned design.

I realize I haven't given you a turnkey answer to your request,
but I at least wanted to give you the lay of the land.

At the 20 acre N6RK QTH, I have moved on from the loop and just
completed a 9 element, 290 foot diameter, circular receiving
array.

BTW, thanks for the DC mult in the recent CQWW160.  You
obviously heard well enough to go coast to coast, but
then, people tell me I have one of the louder signals from this region.

73
Rick N6RK
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Re: Topband: Looking for recommendation for cutting tool for RG-6 with CCS center conductor

[Richard (Rick) Karlquist]

On 2/4/2021 7:09 AM, Fred Moeves wrote:

I got a cheap set from Home Depot.
Ideal 33-522   Internet #300134420

Works on DXE RG-6 both kinds of cable.
Works good for me.

73

Fred KB4QZH




I think Fred is actually referring to Ideal 45-074.
A reviewer of 45-074 on Amazon ("Jeff") wrote:

"I made the mistake of attempting to cut the center core of RG-6 (cable 
tv coax) and that copper is too hard and make a nick in the cutter. I 
won't make that mistake again."


The product description says:

"Steel reinforced center conductors can be trimmed with bolt cutting holes."

Too many red flags here ...

73
Rick N6RK
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Topband: Looking for recommendation for cutting tool for RG-6 with CCS center conductor

[Richard (Rick) Karlquist]

RG-6 is a special case in that virtually all of it
uses a copper clad steel (CCS) center conductor.
Many fine wire cutting tools are designed strictly
for copper, and can get ruined if used for steel.
I also want the cutter to slice the end off of the
RG-6 cleanly, rather than crushing it and distorting
the circular shape of the coax.

Can anyone recommend a quality cutting tool for RG-6?

73
Rick N6RK
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Re: Topband: CQ 160

[Richard (Rick) Karlquist]

I worked 3 of those in the first 1/2 hour.
Only missed NE.

Rick N6RK

On 2/1/2021 12:22 PM, Wes wrote:
I noticed that too.  NE, KS, SD, ND all missing.  No one on or do we 
have a skip zone?


Wes  N7WS



On 2/1/2021 5:15 AM, Artek Manuals wrote:
Odd hole in the N. America prop� no ND, SD or VE5 all right together 
geographically...h??? 



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Re: Topband: One Way Propagation.

[Richard (Rick) Karlquist]

On 1/16/2021 3:20 PM, Roger Kennedy wrote:


If you have an efficient transmitting antenna, and an accurately calibrated
S Meter, I have found over the decades that most signal reports are pretty
Reciprocal.




73 Roger G3YRO



Even if:

1.  Propagation were always reciprocal.

and

2.  Everyone had a calibrated S meter

and

3.  Everyone used a single antenna for RX
and TX

and

4.  Everyone had the same noise level in their
environment.

There would still be no guarantee that equal S meter
readings would correspond to equal S/N ratios.
For example, you transmit and receive on a dipole, which is
generally better on RX.  If the station at the
other end is (like me) transmitting and receiving
on a vertical, that will make me seem to be an
alligator.

Of course, conditions 1 through 4 are by no means
assured in the first place.

YMMV.

73
Rick N6RK
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Re: Topband: Bev under high power transmission lines

[Richard (Rick) Karlquist]

On 1/15/2021 6:34 AM, Richard King wrote:

I would suggest not putting a beverage there.

Even if the beverage doesn't overlap the power lines, it will still be
noisy because of the alignment.

73, Richard - K5NA

On Fri, Jan 15, 2021 at 5:16 AM Michael Fischer 
wrote:



Instead of a beverage. ise a small "magnetic loop" antenna, such as the 
one I published in NCJ and orient it to null the power line noise.  You 
could also try to use a noise cancelling box with noise antenna to 
cancel the noise from the beverage.


Rick N6RK
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Re: Topband: Oscillation in Narrow band tuned antenna.

[Richard (Rick) Karlquist]

On 1/13/2021 3:13 AM, Rune Øye wrote:


I have been told that Oscillation in Narrow tuned antennas can occur and
make damage to your equipment, radio or amplifier. It is really the first
time I have heard about this potential issue.  On 160m band, I use a


Can you give us more details on this theory?  I've never heard
of it.  Maybe it is something that only applies to modern LDMOS
devices?


Reason for asking is that I have burned the final transistor in my radio
and the final FET`s in my PA is broken. It all happens “out of the blue”.


The first question I would ask is whether you have a shunt RF choke to
provide a DC ground for the antenna.  If you do, verify that the
connections to it are reliable.  I mounted a backup RF shunt in a
little metal box with RF connectors that hangs off the output of
my radio to make sure static never blows up the radio, no matter what
antenna I connect it to.  This was after I left the radio connected
to a dipole that didn't have DC short across it and blew up the first
transistor in the receiver.


73
Rune LA7THA
_


73
Rick N6RK
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Re: Topband: FCP Question

[Richard (Rick) Karlquist]

On 1/9/2021 3:22 AM, Guy Olinger K2AV wrote:

Hi Rick,

An answer to Rick and some number of others with inquiries off reflector




Those with EZNEC V5 or V6, including the demo version, can find the help
reference by starting EZNEC (it's identical in V4/5/6). Click on "Help" in
the menu bar on the main window. Click on "Contents". In the User Manual
window, click on "Search" in the Contents-Index-Search tab row. In the "to
find:" space, type in "closely spaced wires"  without the quotes. Click on
the "List Topics" button.  In the topic list, double click "Closely Spaced
Wires".


Excellent navigation!  I found it easily.  I will quote the relevant
text from it below:

-

Closely Spaced Wires

When modeling parallel or nearly parallel wires which are closely 
spaced, it can be very important to align the segment junctions. That 
is, they should be directly across from each other. This is particularly 
true if the segment length is greater than the wire spacing. As the 
segment length gets shorter compared to the wire spacing, this 
requirement becomes less important. When segment junctions are 
misaligned but need to be aligned, results can change dramatically as 
segmentation is changed.


The easiest way to assure that aligned parallel wires have aligned 
segment junctions is to give the wires identical lengths and numbers of 
segments. If the wires are staggered or different lengths, break them 
into more wires. Make the portions of the wires which are directly 
across from each other into separate wires of equal length and number of 
segments. An example of this technique is shown below, where the long 
wire of a J-pole antenna was broken into two wires. Wire 4 is made the 
same length and given the same number of segments as parallel wire 6. 
The upper wire is segmented to make its segment length approximately 
equal to the segment length on wire 4. (This is a close up view – some 
of the long wire, and its number, aren't shown.)




So I was indeed clueless, but no more.  Basically, all I need to do
is align the segments; who knew?  Certainly isn't obvious.  Now I get 
it.  Very clear writing by Roy, as usual.  The J-pole example is

perfect.

73

Rick N6RK


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Re: Topband: FCP Question

[Richard (Rick) Karlquist]

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

[Richard (Rick) Karlquist]

On 1/8/2021 8:33 AM, Salvatore ["Ted"] K2QMF wrote:

Hello Rick,
Can you point me to the info on N6BT's spiral counterpoise??
Many Thanks and 73,
Ted  K2QMF



I'm also posting this reply to the reflector in case others
are interested.

I couldn't find anything N6BT published on this topic.
I think I learned about it from him at his Visalia booth.

I was able to find this:

https://circuitsalad.com/2015/09/13/vertical-with-tuned-spiral-counterpoise-updates/

The executive summary is:

Assume the feedline terminates in a common mode
choke at the feedpoint.  One output from the
choke connects to the vertical driven element.
The other output is connected to a wire that is
say, 115 feet long.  It goes out from the antenna
17.7 feet, and then is formed into a square 25 feet
on a side.  The far end of the wire is NOT electrically
connected to anything, but is mechanically supported
with a string, etc.   The corners of the square lie on a
circle with a radius of 17.7 ft, and the vertical
is at the center.  The feedpoint, choke and spiral
radial are elevated by 5 to 20 feet above ground.
The idea is that the 115 ft wire is resonant after
taking into account the reduced VF due to ground.
You could try to adjust the wire to resonance by
measuring its impedance at the antenna end against
a ground rod using a VNA, and adjust the length.
So the whole thing fits into a 25x25 foot square.
That should work even on a postage stamp lot.
Anyway, it does look reasonable on EZNEC.

73
Rick N6RK
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Re: Topband: FCP Question

[Richard (Rick) Karlquist]

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
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Re: Topband: W6 to EU openings last night

[Richard (Rick) Karlquist]

On 1/4/2021 12:43 PM, Roger Kennedy wrote:


I didn't come on last night . . . but I've been working across to Texas,
Colorado and Arizona over the past week or so.

What sort of time were your QSOs Rick?  (will look out for you tonight)

73 Roger G3YRO



The openings were around 0400 to 0500 UTC.
(Tuesday morning UTC, Monday night in CA)
Last night I was listening a little earlier
and heard W0FLS working a DH1 station, but
nothing from the EU end was audible, not
even waterfall tracks.

73
Rick N6RK
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Re: Topband: Cage wire performance

[Richard (Rick) Karlquist]

On 1/4/2021 7:05 AM, Kenny Silverman wrote:
where the wires connect at a point on the top, but with a 4 foot spread 
of the wires near the ground. This adds about 15-20 kc to the 2:1 
bandwidth per the model.


Will a 2-wire section like this always behave as a wide/fat conductor or do I 
have to worry about voltage/current in Each wire?

Regards , Kenny K2KW


Just a guess:  I would think with 2 wires, you would be fairly
successful with getting good current sharing, as long as there
wasn't some unbalancing effect, say due to having the vertical
running along side a tower.

With 3 wires, there is some reason to think that the middle
wire wouldn't carry much current if the three wires were
in a plane.  OTOH, if they formed a triangular cross section,
then it would seem likely that current sharing would be good.
In general, you want to emulate a round conductor, as opposed
to a strap.  When straps are used to make inductors, the
current crowds to the edges.  Round conductors don't have
such edges, hence they have good current sharing.

I don't believe NEC is good for modeling this.  You have
to use a tool called "HOBBIES" if you want to do this.
K6OIK has written some articles about this tool.

73
Rick N6RK
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Topband: W6 to EU openings last night

[Richard (Rick) Karlquist]

Last night I was surprised to be able to work
SM0GNU, UR0MC, HA8JI, and almost worked IZ4ZZB
from my central CA QTH.  Especially UR0MC in
zone 16 who gave me a 599 report.  I don't
think I have worked that zone since the ARRL
160 contest during the last SS minimum.
All signals had slow deep QSB.  I had to
listen on the TX vertical as I don't presently
have anything beaming EU, although I'm working
on it.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: This report generated on Sunday, 27-Dec-20 at 20:29.

[Richard (Rick) Karlquist]

On 12/28/2020 8:11 AM, Tree wrote:

Okay - let's end this discussion now.

US1Q has entered the Stew as a check log - he is not eligible for awards.

It is unsportsmanlike to use a remove receiver to help stations get more
points.

Also - please note US1Q was disqualified in the 2020 CQ 160 CW contest.

73 Tree N6TR



In this case, do QSO's with US1Q count for the stations on the other
end of the contact?  Just curious.

73
Rick N6RK
_
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Re: Topband: Stew Perry Contest

[Richard (Rick) Karlquist]

On 12/28/2020 6:49 AM, Stan Stockton wrote:


I can see myself with my thumb over the end of a water hose before the CQ
160 Contest trying to spray water on power line insulators!


73...Stan, ZF9CW
_


This is extremely dangerous!  Don't do it.  The power company
has special equipment for safely washing insulators.

73
Rick N6RK
_
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Re: Topband: 160 L and radials

[Richard (Rick) Karlquist]

On 12/11/2020 6:49 AM, w3...@roadrunner.com wrote:


Bought three acres in the country here in central Ohio, where the
general ground conductivity articles feel we have good midwestern loam
soil. Well, MY soil is more like semi clay but it is agricultural
land. Corn and soy farming in particular.


I frequently see descriptions like the above that seem to
be saying that the suitability of soil for agricultural use
is somehow an indicator of its RF conductivity.  This is not
reliable.  For example, Yolo county California shows a
conductivity of 30 on the FCC map.  The soil is pure clay that
goes down 40 feet.  Except for growing rice, this soil is
fairly useless agriculturally, rated class 4 (the lowest possible
rating for farming).  Even weeds don't grow well.  Of course, YMMV.

73
Rick N6RK
_
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Re: Topband: Suggested Frequency

[Richard (Rick) Karlquist]

On 12/2/2020 12:02 PM, Joe wrote:
Our club is working on a project where we will be able to use a AM 
Broadcast antenna on 160 meters.





Joe WB9SBD
   Th


I wouldn't get too excited about this project.
The big groundplane is nice, but doesn't replace
the "vertical on the beach" at all.  The 5/8
wavelength height is good for a few dB at the
most, and even that isn't guaranteed.   Then
as K9YC found out, there is the matter of receiving.W
Especially receiving while the station is broadcasting.
Before even beginning this project, I would advise
installing a temporary receiving loop at the site
and nulling the AM station as best you can.  Needless
to say, you can't use varactors to tune the loop.
See if you can hear W1AW as a start.  That should
be duck soup from 9-land.  Good luck.

YMMV.

73
Rick N6RK
_
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Re: Topband: Stainless Steel for coil taps.

[Richard (Rick) Karlquist]

On 11/16/2020 7:58 AM, Wes wrote:

Nickel is not OK.

I could tell a war story about gold plating over a nickel barrier where 
the plating shop skimped on the gold.


Wes  N7WS

On 11/16/2020 4:05 AM, Rob Atkinson wrote:

  EF Johnson and perhaps others used steel nuts and
bolts that were plated with nickel.  


I have a war story to tell:

HP used to have pretty gold plated PC boards, which of
course had the obligatory nickel barrier.  I was the
project manager for the HP5334B frequency counter,
which was a cost lowered version of the 5334A model
that used gold plated boards.  By the time of the
B model, HP was doing all new products in "Solder Mask
Over Bare Copper" (aka SMOBC).  No gold or nickel.
I had the front end section of the 5334A PC board
leveraged to use in the 5334B.  Exact same schematic
and layout.  Only difference was the SMOBC process.
Upon turn on of the first SMOBC board, I was not
especially surprised to find out that the front
end circuits now oscillated because the lossy PC
board containing nickel was replaced with just copper.
I had to add back in some loss with damping resistors
to make it stable.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Stainless Steel for coil taps.

[Richard (Rick) Karlquist]

I need to correct some misconceptions:

On 11/16/2020 6:24 AM, Tim Shoppa wrote:

Conductivity of Copper: 5.85 x 10^7 mho/m

Conductivity of 301 Stainless: 0.14 x 10^ mho/m

Stainless is 42 times worse conductor than copper.



1.  Because of skin effect, the surface resistance is
inversely proportional to the SQUARE ROOT of the conductance
at RF.  There, in the calculation above, the square root
of 42 should have been used.

2.  But that would still be incorrect because any magnetic
material will have additional loss at RF above and beyond
mere RF skin effect.  This loss is difficult to quantify
but should be assumed to be substantial.

[BTW, does anyone know if so-called "non magnetic" stainless
steel is free of this effect at RF by virtue of not being
attracted to a magnet?]

There was also some mention to the effect that nickel was
a "non-ferrous" metal and therefore would be good at RF.
Nothing could be further from the truth.  Although technically
"non-ferrous", nickel is nevertheless "ferromagnetic".
I once measured some nickel strap material for RF loss
and it was horrific.  Much worse than even what its DC
resistivity would suggest.

An additional factor with various stainless steels is that
some alloys naturally form an oxide layer, along the lines
of aluminum.  I can easily imagine wrapping a stainless
clamp around copper tubing and have high contact resistance
on account  of this.  This is no mechanism for puncturing
the oxide and forming a gas tight seal like you would have
in a crimped connection.  IMHO, this is the more likely
reason for the pyrotechnics.  My conclusion is that the
technique is in the "too clever by half" category.

73

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: OT - Bonding Radials at Intersections

[Richard (Rick) Karlquist]

On 11/6/2020 1:10 PM, Carl Clawson wrote:

Frank,

“Must” is a strong word. What goes wrong if you cross them?

73, Carl WS7L



Also, if insulated wires are used for radials that cross
over each other, is that to be treated differently than bare
metal wires that cross over each other and touch
so as to have electrical connectivity?

Does it matter if cross over radials are soldered at the
crossovers, so as to prevent parasitic "diodes".

For whatever weird reason, the price of insulated wire is
nearly always lower than the equivalent bare wire.  And
Romex sells for less than the equivalent individual wires.

Rick N6RK
_
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Re: Topband: Looking for a 2n5109

[Richard (Rick) Karlquist]

On 10/22/2020 9:22 AM, Edward stallman wrote:
I remember about a year ago a discussion not to buy the 2n5109 
transistors from E-Bay sellers . Some searching shows the 2n5109 has 
been discontinued for many years . So is anyone that's been saving one 
for many years willing to part with it ? I'm using it in a W7IUV pre-amp .


Thanks Ed N5DG




Mouser has them in and out of stock.  I ordered some
6 months ago, and they came in about a month later.

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: 160m activity

[Richard (Rick) Karlquist]

On 10/9/2020 8:26 AM, VE6WZ_Steve wrote:

There is still a great deal of CW activity on 160m !

What we need is more guys calling CQ and less just listening and saying that no 
one is active!


In the Summer Stew, I enjoyed a good rate for an hour or two after west
coast sunset, then my rate dropped to single digits after
almost everyone went QRT.  Let's see if we can get more
activity next week.  At the least, propagation will
begin at an earlier time.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: RX Power over Coax

[Richard (Rick) Karlquist]

On 10/7/2020 7:45 AM, Grant Saviers wrote:

Rick,

Did you CM choke the power and signal leads?  or the whole cable?

Grant KZ1W



I should clarify that the CAT-5 was only used
to drive relay coils.  It did not power up a preamp, because
I did not need a preamp.  In place of a CM choke on
the RF coax, I used a flux coupled transformer,
either a Mini-Circuits T9-1 or a homebrew one
using a binocular core.  (The transformers were
used with Beverages).  The substantial drop
in signal level when the relay was de-energized
indicating that the transformer was providing
sufficient de-coupling.

Using a separate DC feed allows the option of using
a flux coupled transformer instead of a CM choke.
There seems to be a knee jerk reaction in favor of
using CM chokes vs flux coupled transformers.
A small transformer has very little interwinding
capacitance and could provide more isolation than
a CM choke.  And with Beverages, it is needed anyway.

73
Rick N6RK

_
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Re: Topband: RX Power over Coax

[Richard (Rick) Karlquist]

Exactly right.  I had trouble with "critters"
chewing my coax.  Nothing bad happened until
it rained.  Then the rain got into the coax
and the water interacted with the
DC voltage on the coax; terrible noise.
With the DC off, there was no noise even
when soaked.

I converted the DC feed to CAT-5 cable and the
problem disappeared.  Another advantage of
CAT-5 is that you get 8 conductors, all
independent of the RF coax and the earth
ground.  Also, for whatever reason, critters
don't like it :-)  The RF coax was eventually
stuffed thru 1,000 feet of cheap sprinkler
pipe repurposed as "conduit".  Good enough
to keep the critters out and rain out.  But
I elected to keep the CAT-5 for DC.

73
Rick
N6RK

On 10/6/2020 3:09 PM, donov...@erols.com wrote:

Hi Lee,


Your testing will be inconclusive unless you inject water into your
connectors, or you could just move to Maryland where we get at least
45 inches of annual rainfall and it gets into everything thats not well
waterproofed


73
Frank
W3LPL



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

Re: Topband: [bevantennas] Ground screen under beverage....

[Richard (Rick) Karlquist]

On 10/1/2020 10:53 PM, donov...@erols.com wrote:


The engineer who lead development, testing and evaluation of the array
explained that the ground mats served two purposes:

- almost completely suppressed signals received by the sloping ends of the
Beverages by making them into efficient transmission lines with very low
spurious signal leakage compared to a sloping wires over poorly conducting
soil or vertical wires at each end of a Beverage.
W3LPL




I don't buy the engineer's reasoning here.  If we use superposition
into vertical and horizontal electric fields, it seems to be apparent
that the ground mat would do nothing to prevent the last 50 feet from
acting like a sloping vertical with respect to vertically polarized
waves.  If anything, it would make the vertical work better, as
verticals always do when radials are added.

I could believe that the mat would prevent the last 50 feet from
acting like a Beverage, but that "solves" what is a non-problem.

I think everyone including the engineer agrees that 4 vertical
feet is 4 vertical feet no matter how many horizontal feet
are added.  Because of superposition.

I am thinking that a very simple test of this would be to
do an A/B test of the pattern with only the last sloping 50 feet
connected, comparing with and without the mat.  I'm surprised
that the engineer didn't do this as confirmation.

Is there any article that establishes that the 4 foot vertical
drop at the end of the Beverage is actually significant to
the overall performance of the Beverage?  I've never seen such
an article myself.  It is hard to imagine that only 4 feet of
conductor would pick up much signal.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Beverages and VK

[Richard (Rick) Karlquist]

On 9/16/2020 8:46 AM, Tree wrote:


antenna.  At a previous QTH - I would sometimes find a low dipole buried in
a small ravine was my best RX antenna.  Another indicator that a high angle
was a play.

Tree N6TR



Observed same thing here with 1/2 wave dipole at 30 feet high.
A similar dipole at 60 feet didn't receive any better.
The beverages rarely beat the dipoles in quality of copy.

Rick N6RK
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Re: Topband: Horizontal Waller Flag

[Richard (Rick) Karlquist]

On 9/12/2020 5:26 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.




You didn't mention what kind of coax you used, but unless you
proactively seeked out double shielded, it WILL leak.  I used
to work for Hewlett-Packard/Agilent/Keysight.  At one time, HP
has it's own captive wire manufacturing factory.  One item of
interest for this discussion is that they made their own
TRIPLE shielded miniature coax to be used in instruments.
They had some connector vendor make special connectors to fit
this HP only coax.  In the old HP measurement accessories
catalog, there were "RG-58" class test cables with BNC connectors
colored in HP "mint gray".  These were not ordinary RG-58, but
were double shielded.  Compared to the black Pomona test cables you
can buy from distributors, the leakage was drastically less.

It is also not surprising that CAT-5 cable has less leakage.
I have used it myself as feedline.

At BCB frequencies, you also have to contend with the skin depth
problem.

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Horizontal Waller Flag

[Richard (Rick) Karlquist]

On 9/11/2020 8:06 AM, David Cole via Topband wrote:


My next and final problem - when I have the tower retracted approx 25ft and the 
fiberglass stub mast I have good acceptable directivity - If I then raise the 
tower by 20 feet then the polar plot is and directivity disappears - lower the 
tower back down and the polar plot returns to normal.
I did have a masthead preamp installed I removed this - no difference - I then 
put ferrites around the rotator cable and a common mode choke at the bottom of 
the tower thinking that the coax lead which was originally coiled on the floor 
with the mast down was now acting as a vertical antenna - none of these made 
any difference. my direct email is d...@g3rcq.com

Thanks from Dave g3rcq



I ran into a problem like yours with tower raising.  It turned
out that the feedline was acting as a vertical antenna and
the actual RX antenna did not have adequate feedline isolation.
When the tower is lowered, the unintentional vertical antenna
goes away.

As far as ferrites around the cables, etc not working:
you didn't say what you used, but it was clearly inadequate.
Common mode choking in the BCB is quite difficult to pull off.
Sliding beads onto the rotator cable definitely won't work.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Rohn 25 Vertical questions.

[Richard (Rick) Karlquist]

On 8/19/2020 10:28 PM, donov...@erols.com wrote:

Hi Ron,


700-1200 foot spacing should provide good in-band receiving capability.
SDR receivers won't work for in-band receive, you must use a traditional
transceiver such as the K3, K4HD, FTdx5000, IC-7800 etc.


Micro-arcing is caused by transmitted RF jumping a spark gap.
Any metal-to-metal joint that isn't securely bonded is a candidate
for micro-arcing.


73
Frank
W3LPL




Three questions:

1.  Does "in-band receiving" mean the same thing as SO2R in a single
band contest?  I operated a few 160 meter contests in that mode around
10 years ago.  I used a carefully nulled receiving loop 1000 ft from the
TX vertical.

2.  Please explain the comment about SDR receivers not working.  I
now have a Flex 6700 that claims to be able to do full duplex.  And
that radio would not work?

3.  If connections between R25 sections cannot be trusted, then
how would any crank up tower possibly work as a vertical?  I have
always wondered about this.

BTW, cellular sites have significant problems with what they
call "passive IMD", of which micro-arcing is a subset.

73
Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Windows 10 Update heads up

[Richard (Rick) Karlquist]

I still prefer Windows 7 too...

73, Luke VK3HJ



Windows 7 wasn't a safe harbor in the
first place.

Last October, I was running Win 7 for my PC with
Flex installed.  An update blew out the CAT driver.
As a result, I missed the Stew Perry.

To make a long story short:  Flex and their 3rd
party driver supplier told me they no longer
support windows 7.  I ended up using an out of
date win 7 machine for the rest of the year,
then in January I updated all machines to Win10.
That luckily went amazingly smoothly.

Now that Win 7 no longer gets auto updates, I
guess it is Flex proof.  Of course it is vulnerable
to every other attack.

I don't use my shack computer with auto updates turned
off to do anything but ham radio.  So I am less concerned
about having the updates off.  MS makes it difficult to
easily turn updates on and off.  You have to go about 10
levels deep in the menus and the choices are not obvious.
I had to save a cheat sheet I found on line to remember
the menu picks.  I'm glad I paid for Pro Windows.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Windows 10 Update heads up

[Richard (Rick) Karlquist]

On 8/16/2020 8:21 AM, Anthony Scandurra via Topband wrote:

There is no monthly, yearly, or ANY fee for running a Flex radio.  There is an 
UPGRADE charge when going from one major revision to the next (for instance, 
from version 2.x to 3.x) which is OPTIONAL.  You don’t need to perform the 
upgrade unless the added features appeal to you.

73, Tony Scandurra
ARS K4QE - FM05fv




In fairness to Flex, they continue to issue bug fixes
to version 2.  You only have to switch to version 3
if you want the new features.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Windows 10 Update heads up

[Richard (Rick) Karlquist]

On 8/14/2020 1:26 PM, Brad Rehm wrote:

Phil,

I've turned off updates for the maximum allowed 35 days on Pat's and my
computers but not on my new laptop.  I use it occasionally to access my
Flex, so it will be my "canary in the coal mine" for future updates.  For
now, if it survives the next couple weeks, I'll allow the other updates to


Regarding Flex:  that is a special case.  I have numerous W10 computers
on auto update.  The updates have never broken the OS or any ordinary
applications.  They have only ever broken Flex, who admits they don't
know how to completely fix the audio and CAT drivers, and they say that
have gotten no help from MS or the 3rd party that supplies the drivers.
The Flex is not a good canary because it can be knocked out by updates
that do nothing to other computers that are not running Flex.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Windows 10 Update heads up

[Richard (Rick) Karlquist]

For Flex users:

For the second time in less than a year, a Windows 10
update disabled my Flex CAT and DAX drivers.  After hours
of time spent with Flex, I learned I am supposed to
disable auto updates.  Also, before doing
an update manually, I was supposed to uninstall the
Flex software.  Now I am told that the drivers have been
"improved" for now, but are still vulnerable depending
on Microsoft, but it "probably safe" to update without
uninstalling, as long as the Flex software is not running
at the time.  I was also told that only 2.4.10 and 2.6.2
and version 3 something are "fixed".  I was running 2.6.1.
Who knew?  Nothing up on their web site.

My new procedure will be to check for windows updates on
Monday after the contest is over and log submitted.

Last year I missed the Oct. Stew Perry on account of this.

Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: 1610 KHz AM Channel in USA

[Richard (Rick) Karlquist]

Any BCB radio with a ferrite bar antenna can
usually null out power line "noise", etc.
Of course, that noise/QRN is not the proverbial
Additive White Gaussian Noise (AWGN).  Maybe
you meant to say "noise isn't always AWGN".

73
Rick N6RK

On 7/5/2020 3:34 AM, Rob Atkinson wrote:

Tnx for clarification.


I don't know what "noise is usually AM" means.


Hi, I guess I was thinking of RFI from appliances and arcing contacts
on power lines.

73
Rob
K5UJ
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Re: Topband: 1610 KHz AM Channel in USA

[Richard (Rick) Karlquist]

On 7/4/2020 4:35 PM, Rob Atkinson wrote:


I'm not following the reasoning here.  How are listeners never
fighting noise below 1710 kc?   In some cases noise (or by noise are
we thinking of QRM?) is worse on medium wave broadcast channels
because noise is usually AM and so are the desired signals.  Also the
receiver passband is wide.   Those TIS stations usually run only 30 to
50 watts and use physically small antennas.

73

Rob
K5UJ



If I listen on my 90 foot vertical, and get a noise level check
at, say, 1750 kHz and then start tuning from 1710 kHz down, there
will be no channel where the S-meter gets down to the
reference noise level at 1750 kHz.  This isn't because there is
more noise below 1710 kHz; rather every channel has one or
more stations that are well out of the noise.  This will be true no
matter what receiver bandwidth is used.  Especially at night.
There may be signals buried in the noise, but they will
always be covered up by stronger signals.  When I had my
beverages up, I remember hearing TIS stations up to 100 miles
away, FWIW.

I don't know what "noise is usually AM" means.

73
Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Adding 80m to 160m receive array

[Richard (Rick) Karlquist]

On 7/4/2020 9:21 AM, gjpur...@gmail.com wrote:

For those using uses short, umbrella wire loaded verticals, I've posted an
article on adding 80m to a 160m array. It can be viewed or downloaded at:
https://w6ayc.com/w6ayc-adding-80m-to-a-160m-receive-vertical/.



73   Joe W6AYC



At the top of page 2, 2:1 VSWR is given as the bandwidth criterion.
That is somewhat irrelevant for phased arrays.  In that case, the 
critical issue is to have phase (especially) and amplitude tracking 
between elements in the array. It would be a lot easier to do that on 2 
bands by simply using relays to select individual networks for each 
band, that could be optimized for each band, without interaction between 
the tuning adjustments. This would also allow having a different
series resistor for each band. The control voltage could run down the 
center conductor of the feedline.


73
Rick N6RK
_
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Re: Topband: 1610 KHz AM Channel in USA

[Richard (Rick) Karlquist]

On 7/4/2020 8:55 AM, Tree wrote:

Been testing my new SW Beverage using the 1610 kHz channel.  This channel
is mostly (if not entirely) low power stations - including the TIS



Tree N6TR
_


I used to have three 400ft bidirectional beverages that aimed at
30, 90, 150, 210, 270, and 330 degrees azimuth.  I always
used BCB stations as "sanity check" beacons to verify that they were 
working OK.  On many channels, I could hear 3, 4 or even 5 different

stations independently on as many beverages.

The length was limited to 400 feet because of my high conductivity
ground (not because I didn't have enough space).  They worked
fabulously down to the bottom end of the BCB, even though they
were way too short for those frequencies.

All of this success for BCB listening doesn't mean jack on 160 meters.
On the BCB, you are never fighting noise, rather just separating 
different stations.  They did also do that on 160 meters, for example, 
letting me work JA's even when stateside stations were also calling me.

What they never did well was to bring the DX out of the noise, I
guess because they were less than a wavelength long, and effectively
even less than that because my high ground conductivity attenuation
rolled off the current.  (I measured it with a current probe).
On 80 meters they started to work, and on 40 meters they were
amazing, for example, long path to EU in the morning.

As always:  YMMV!

73
Rick N6RK
_
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Re: Topband: Summer Stew Perry

[Richard (Rick) Karlquist]

On 6/21/2020 3:41 PM, List Mail wrote:

I worked K7RAT (with some difficulty) and that was all.




Luke VK3HJ



From California, the band was basically only active
from sunset until about 0500Z, at which point K7RAT
was the last man standing, and it didn't seem like
he had much rate.  He was something like 40 dB over
S9 here!   After CQing for 10 minutes without
any calls, I went QRT.  Only ZL was in the dark by
then.  I was too tired to stay up until VK was in
darkness.

For the brief time when there was some activity, the
propagation to the east coast was great.  A dozen or
two stations in the FM grid field were easily worked.  After
the contest, I got an email from an Ohio station
saying I was the only station he heard west of the
Mississippi.  So maybe I was in the spotlight.
Come to think of it, I didn't heard any east
coast stations CQ'ing.  They were all responding
to my CQ.

K7RAT to some extent made up for KV4FZ not being
there :-(  He was often the last man standing in this
contest.

Anyway, I think we have established that the band
works just fine at our Summer Solstice and we just
need more activity for this contest.  Before this
contest was started a few years ago, I had the
mistaken impression that the band was dead in the summer.

Rick N6RK
_
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Re: Topband: Tuning a 2el parasitic array

[Richard (Rick) Karlquist]

On 6/21/2020 7:06 AM, VE6WZ_Steve wrote:

This morning I uploaded a YouTube video explaining the method for tuning any 
2el parasitic array.

I do some experiments in my workshop using the Nano-VNA on a small 2 el Yagi to 
explain mutual coupling. Then using 4NEC2 I show the relationship between the 
dip in real R (point of maximum coupling) and the F/B and gain of the array.

Using this understanding any 2 el parasitic array can be tuned with confidence 
on the tower by only sweeping the driver with the antenna analyzer.  There is 
no need to isolated the driven element and do analyzer sweeps on the parasitic 
element. This method is especially useful for tuning arrays with non-split or 
grounded parasitic or driven elements.

This is the method I used for tuning my 2 el 160m parasitic array that uses the 
shunt-fed (grounded) tower as a driver.

https://youtu.be/2DcvmGPLdT0 

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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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Soldering aluminum coax shield to copper wire

[Richard (Rick) Karlquist]

On 6/1/2020 8:11 PM, Jim Brown wrote:

On 6/1/2020 7:42 PM, Chuck Hutton wrote:

I wish to solder copper wire to the shield.


I understand the question, but since you've so far received no 
responses, I wanted to point out what "the industry" and other hams have 
done.


73, Jim K9YC



OK, I'll give a response:

At the 2014 Dayton Hamvention, there was a guy
selling what was marked:

"Low Temperature Aluminum Repair Rod."

I purchased a few dozen rods, but never used them.

They came with a very detailed instruction sheet
that said they could be mail ordered from the
guy at this address:

Robert Dunbar
453679 Creek Avenue
Afton, OK 74331

I checked QRZ, and he doesn't appear to
be any of the 7 "Robert Dunbar" hams
on QRZ.  You could invest 55 cents and mail
to the address I showed.

BTW, the instructions specifically recommended
against your motor oil method.  Instead, the
work piece must be degreased.

I also googled "Low Temperature Aluminum Repair Rod"
and the first hit produced:

aluminumrepair.com

This site seems to be the motherlode for this stuff.
They certainly talk a good game, just like the guy at Dayton did.
The site owner is "New Technology Products" in Houston, FWIW.

If you try these out, post your results, good or bad, on this
reflector.

Good luck!

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: 160m Vertical

[Richard (Rick) Karlquist]

On 5/16/2020 4:31 AM, Rob Atkinson wrote:

On 5/15/2020 8:27 AM, donov...@starpower.net wrote:

""A more reliable approach is a tuner in your shack. The extra coax
cable loss from elevated VSWR is insignificant on topband.""




Another disadvantage of a tuner at the shack end is that the match
bandwidth for any given setting of the tuner becomes narrower.
I have over a full wavelength of open wire line to my 160m
vertical.  No problem with power handling, VSWR handling or loss,
but the match bandwidth is very narrow if the OWL is badly
mismatched.  There is a 450 ohm to 50 ohm balun/transformer at
the tower, so I only have to match the antenna to unbalanced
50 ohms.  There is another transformer at the shack end.

I should also point out that the charts showing "Additional loss
due to SWR" were incorrect for decades in various ham publications
and were only recently corrected, in case you hadn't heard.

See:

https://ac6la.com/swrloss.html

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: INV L matching

[Richard (Rick) Karlquist]

On 5/14/2020 9:26 AM, Tom | SP5XO wrote:

d,
wideband match. Since short vertical inv L over reasonable ground should
have roughly 20 OHm impedance that could work here as well.


The matching network that will maximize bandwidth
is an autotransformer wound on a 2.4 inch diameter
ferrite core.  For example, a transformer with a
3:2 turns ratio will transform 50 ohms to 22.2 ohms.
I use a homebrew autotransformer on my 90 foot
vertical which has around 25 ohms drive impedance.
See Jerry Sevick's book on RF transformers for
info on "un-uns".

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Herbert Schoenbohm, KV4FZ: Silent Key

[Richard (Rick) Karlquist]

I am happy for him that he lived long enough to get his
license restored.

Rick N6RK

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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: [TowerTalk] Measuring resonance of a yagi element

[Richard (Rick) Karlquist]

On 4/23/2020 7:40 PM, VE6WZ_Steve wrote:

Tom,

Yes.
Just sweeping from the end of the coax in the shack should show the same dip of 
R at the correct frequency.
(The absolute R value (in Ohms), and X value will not be correct because of the 
feedline transformation, but the frequency of the R dip is ONLY a function of 
the reflector tuning.)  Try it and see.



I don't see how this would be true for an arbitrary length
of coax, especially if it is an odd multiple of a quarter
wave.  For example, if the load on the far end changes
from 50 ohms to 25 ohms, the analyzer in the shack will
see resistance INCREASE from 50 to 100 ohms.  A line with
electrical length of 55 degrees will have a resistance
at the shack of 50 ohms whether terminated in 50 ohms
or 25 ohms.

73
Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: BCB Filter Recommendation?

[Richard (Rick) Karlquist]

On 4/17/2020 6:22 AM, Joe wrote:

Is radio manufacturers that include steep filters and even attenuators 
in their radios to block AM Broadcast band signals. Then advertise that 
their radio covers from 50 KC to 60 Mhz!

Sorry NO IT DOES NOT!!!

It is extremely sad when a ten buck radio with it's internal ferrite bar 
antenna performs better than my $4000.00 dollar radio using a 600 foot 
loop up 60 feet antenna!


Joe WB9SBD
Sig


The AM BCB is unique, compared to 160/630/2200 meters, in that every
channel is occupied by multiple strong signals 24/7 that are strong
enough to overcome receiver noise with a tuned ferrite bar antenna.
A 600 foot loop is omni directional and horizontally polarized and
thus IMHO is a non-starter for BCB DX.  If you want to go beyond the
ferrite bar antenna, you could put up short beverages.  I used to
have six beverages spaced at 60 degrees azimuth that were only 400
feet long.  Although "too short" for BCB, in fact they were VERY
directional.  On a typical channel, at least 3 different stations
could be received, each on its own beverage.  In some cases 4 or
5 different stations could be heard.  My pocket size Sangean radio
($60 not $10) has amazing nulling capability for power line noise
due to its small antenna (better nulling than a big loop).  I
remember an amazing incident with this radio when I was listening
to a station in San Diego on 770 kHz IIRC and I accidentally turned
the radio so as to null out this station.  Up popped WJR in Detroit.
Not bad AM DX for a pocket radio on the left coast.

And now back to HAM radio.

73
Rick N6RK
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: BCB Filter Recommendation?

[Richard (Rick) Karlquist]

On 4/16/2020 2:45 PM, Jeremy Maris wrote:

Make your own!

Use this site to design your filter.

http://www.iowahills.com/9RFFiltersPage.html

Attached are the values I used back in 2016 when the G4AQG FT-1000MP had 
intermod problems with a new Beverage.

I built a 9 pole Chebyshev high pass filter, designed with the excellent RF 
filter design package from Iowa Software, and used an LC meter to get the 
capacitor and inductor values correct. Caps were made from polystyrene and 
inductors wound on small ferrite torroids..

Difficult to see from the (ancient!) spectrum analyzer picture but the filter 
response was almost exactly as the design showed.
No labels for stop-band but it was 10dB down at 1579kHz, 50dB down at 1000kHz 
and at 693kHz was in the noise, at least 70dB down, almost undetectable 
compared to 60dB over S9 or more without the filter, and the  intermod was gone.



The good filters use INVERSE Chebyshev designs,
made with mica or C0G capacitors, and powdered iron cores.
10 dB down at 1579 kHz is not good enough for many QTH's.
I have a very strong local station at 1700 kHz,
for example, and another at 1530 kHz.

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: RG-6 Delay cables

[Richard (Rick) Karlquist]

On 4/8/2020 1:28 PM, Lee STRAHAN wrote:


Even if the copper center conductor expands, the way the cable connectors 
are made allows the copper to simply push in the connector  past the connection 
point maintaining its physical length.


Very astute.  You may have explained this paradox.
I didn't think of this type F effect.  Some type N
connectors also work this way.

73
Rick N6RK

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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: RG-6 Delay cables

[Richard (Rick) Karlquist]

On 4/8/2020 10:37 AM, Lee STRAHAN wrote:

Good morning from Oregon Top-Band people,

Cable loss was -.61 dB at 59 Deg. F,  And -.58 dB at an averaged cable 
temperature of 23 Deg. F.
59 Deg. F  23 Deg. F
1 - 74.59 DEG  -74.60  DEG.
2 - 74.59 DEG -74.60  DEG.
3 - 74.59 DEG -74.60  DEG.
4 - 74.59 DEG -74.60  DEG.
5  -74.60  DEG -74.60  DEG.
6 -74.60  DEG  -74.60  DEG.
7 -74.60  DEG  -74.60  DEG.
8 -74.60  DEG  -74.60  DEG.
9 -74.60  DEG  -74.60  DEG.
10 -74.60  DEG-74.60  DEG.

My bottom line conclusion is that for our purposes on the top-bands I no longer 
wonder if the cable delay and attenuation remained constant with winter 
deployed arrays.
Incidentally, T Snap and Seal have been the best connectors here for 
repeatability.

Lee Strahan
K7TJR



These numbers seem too good to be true.
The tempco works out to less than 7 PPM/°C.
Consider that the coefficient of thermal
expansion of copper is +17PPM/°C.

Refer to Figure 7 of this:

https://www.timesmicrowave.com/DataSheets/Literature/Current%20innovations%20in%20phase%20stable%20coaxial%20cable.pdf

The graph on the right shows non-linear tempco curves.
When you have non linearity like this,
it is possible to pick two points on the curve
such that a line drawn through them has a slope of zero.
Maybe you ran into that.

The numbers you reported for the loss seem roughly
consistent with what the thermal coefficient of
resistance of copper predicts.

Rick N6RK
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector