Re: Topband: question about matching network for short vertical RX antenna

[Matt Murphy]

I realized the attached Smith chart image did not come through on the
reflector so I posted it on the web, here is the chart:

https://www.dropbox.com/s/nwfqr6xhsfdgjjb/Screenshot%202017-03-09%2013.03.33.png?dl=0

73, Matt NQ6N

On Thu, Mar 9, 2017 at 12:46 PM, Matt Murphy <m...@nq6n.com> wrote:

> In preparation for the Stew I'm thinking of setting up a two element
> end-fire array aimed at Europe, and possibly another one aimed south.
>
> I've done some reading about these types of arrays and I think I understand
> the approach taken by W8JI in his design of the short verticals he uses, as
> well as the design of the YCCC short vertical.
>
> Just for kicks I decided to model a short vertical that used matching stubs
> made with RG-59.
>
> I'd like to ask for advice on this approach.  I would use the array on 160m
> only, and the objective is for it to have better RDF than my inverted L, so
> even a few dB would be helpful.
>
> I modeled a 6' vertical element in CocoaNEC and designed a matching network
> using SimSmith.I have attached the Smith chart of the matching stubs.
>
> In my CocoaNEC model, the feed point impedance does not change much if I
> increase the length of the element to 30', and the matching network is not
> sensitive to changes in the feed point impedance.  I wonder if this
> matching network might just be equivalent to matching the coax with no
> antenna connected (and if so what that means for the antenna's performance)
>
> Any advice on the antenna, matching network, etc., would be much
> appreciated.  My next step is to build one and verify that my real world
> results for a single element match the model's prediction, and if so, to
> subsequently build a second one and connect them with a phasing line to
> achieve end-fire directivity over the bottom end of 160m.
>
> Advice much appreciated.
>
> 73, Matt NQ6N
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Topband: question about matching network for short vertical RX antenna

[Matt Murphy]

In preparation for the Stew I'm thinking of setting up a two element
end-fire array aimed at Europe, and possibly another one aimed south.

I've done some reading about these types of arrays and I think I understand
the approach taken by W8JI in his design of the short verticals he uses, as
well as the design of the YCCC short vertical.

Just for kicks I decided to model a short vertical that used matching stubs
made with RG-59.

I'd like to ask for advice on this approach.  I would use the array on 160m
only, and the objective is for it to have better RDF than my inverted L, so
even a few dB would be helpful.

I modeled a 6' vertical element in CocoaNEC and designed a matching network
using SimSmith.I have attached the Smith chart of the matching stubs.

In my CocoaNEC model, the feed point impedance does not change much if I
increase the length of the element to 30', and the matching network is not
sensitive to changes in the feed point impedance.  I wonder if this
matching network might just be equivalent to matching the coax with no
antenna connected (and if so what that means for the antenna's performance)

Any advice on the antenna, matching network, etc., would be much
appreciated.  My next step is to build one and verify that my real world
results for a single element match the model's prediction, and if so, to
subsequently build a second one and connect them with a phasing line to
achieve end-fire directivity over the bottom end of 160m.

Advice much appreciated.

73, Matt NQ6N
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Re: Topband: "Thinking out loud"

[Matt Murphy]

This appears to be the 4O3A unit.  I hadn't realized these existed, so I'm
glad you posted the question:

http://www.4o3a.com/index.php/products/ham-radio-gear/crystal-front-end-unit/

On Thu, Dec 22, 2016 at 3:47 PM, K1FZ-Bruce  wrote:

>
> Thanks Mirko,
>
>
> Very Good information.   What is needed is to reduce noise more (lower)
> than signals.
> 73
> Bruce-k1fz
>
>
> On Thu, 22 Dec 2016 22:36:30 +0100, S57AD  wrote:
>
>   As far as I recall, Inrad sells front-end xtal filters. Some 25
> years ago
> when I lived in Belgrade, at YU1EXY we had two six-pole filters for SSB
> part of 40M band but I can't recall and difference with or without those
> filters. Beside those two xtal filters we used 8 pole Cohn LC filter with
> 4-gang variable capacitor and with very step curve (I think it was 600 or
> 800 Hz at -6 dB), which drastically reduced noise and QRM. We could hear
> 3rd or even 4th layer of callers in 40m pile-ups.
>
> As for xtal front end filters, I think 4O3A produces such a filters to be
> used at in-band stations, but didn't have chance to try & use them...
>
> 73, Mirko, S57AD
>
> 2016-12-22 21:57 GMT+01:00 K1FZ-Bruce :
>
> > Tim,
> >
> > My single crystal was in the 1950's.
> > A crystal lattice could take in much of the 160 meter band and be
> > pratical.
> > Thanks for your input.
> > 73
> > Bruce
> >
> > On Thu, 22 Dec 2016 15:49:12 -0500, Tim Shoppa wrote:
> >
> > Bruce - It has long been rumored that the big EU multi-multis have
> > a crystal filter at their run frequency receivers. e.g. if they are
> running
> > on 7003.4, they have a crystal filter in front of their receiver for
> > 7003.4. have never observed that in my visits but maybe in decades past,
> > when receivers had less damage range, it would've made sense. Also a good
> > reason to put up a fight for ownership of YOUR run frequency HI HI
> >
> > I believe EMRFD has a schematic for a single-frequency receiver, maybe
> > not exactly like you described but similar in principle. Let me see if I
> > can dig it up.
> > Tim N3QE
> >
> >
> > On Thu, Dec 22, 2016 at 3:41 PM, K1FZ-Bruce wrote:
> >
> >
> > We know that limiting the noise pick up from more directions of an
> antenna
> > we can usually hear better. We also know if we limit the noise from a
> > receiver IF we can hear less noise, and better yet, if we
> > have a roofing filter earlier in the receiver we can eliminate even more
> > noise in relationship to the wanted signals.
> > What if we take it a step further, could we limit the band-with of the
> > antenna signal with a crystal lattice for 160 meters before the receiver.
> > Years ago I played around with a single crystal at the input of an old
> > tube type receiver. It was remarkable what I could hear on 40 meters,
> > on what seemed to be one frequency.
> > 73
> > Bruce-k1fz
> > http://www.qsl.net/k1fz/beverage_antenna.html
> _
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>
>
> - End forwarded message -
>
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Re: Topband: Improving condx?

[Matt Murphy]

Superb conditions to EU from IL last night as well.  Definitely the best
top band conditions I've experienced.

Matt NQ6N


On Wed, Dec 7, 2016 at 1:56 PM Art Snapper  wrote:

> Conditions to EU were better than I have seen so far this season I was only
>
> on from 0430-0500z, but even that was impressive.
>
> Tom 4O/KC0W was very loud. In fact, he was louder than he is at our sunset
>
> peak.
>
>
>
> 73
>
> Art NK8X
>
>
>
>
>
>
>
> On Wed, Dec 7, 2016 at 2:46 PM,  wrote:
>
>
>
> > Greetings Topbanders. . .
>
> >
>
> > I got on the air on TB late last evening about 11:00 p.m. Central
> Standard
>
> > Time and had a pleasant surprise.   I had been QRV 160 earlier in the
>
> > evening and found conditions to EU to be poor (when I have trouble
> copying
>
> > SV3RF, F5IN, HA8RM, etc., things are bad).  However, I got back on later
>
> > having suspicions that maybe conditions were beginning to improve so I
>
> > started calling CQ.  I was pleasantly surprised and ended up working 32
> EU
>
> > stations (not a bad run from here in the Midwest).  It wasn’t a
> continuous
>
> > run as I stopped to tune around from time to time to see what else might
> be
>
> > going on.  I could have worked more stations but was tired and went to
> bed.
>
> > The real surprise was well over half the EU stations worked were either
> new
>
> > call signs for 160m or all time new call signs.  I was careful to make
> sure
>
> > I was getting call signs accurately so I’m confident the “unique” call
>
> > signs were indeed valid.  As we get further into the season I’ve noticed
>
> > the past week or so this pattern of improving conditions as EU SR
>
> > approaches.  It most definitely has not always been that way this season
>
> > here in Iowa.   In any case, it might pay for you stateside guys to stay
> up
>
> > a little late as EU seems to waiting.
>
> >
>
> > 73 and compliments of the Season. . .Dave, W0FLS
>
> > _
>
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Re: Topband: advice on simple end fire array

[Matt Murphy]

Tim, that sounds like good advice.  I had been thinking that the end-fire
array would offer a chance for me to dig into some of the math and low-end
test equipment creating the transformers, but I think your broader point
that being able to improve SNR at a range of azimuths is likely far more
beneficial in the Stew than simply focusing on EU.

Could you describe how you had your two arrays phased and what improvement
you initially noticed (when you had the array in place) over a single
array?

73,
Matt NQ6N

On Mon, Dec 5, 2016 at 11:45 AM, Tim Shoppa <tsho...@gmail.com> wrote:

> From where I am in W3, the EU numbers in a Stew (including prestew and
> summer stew) seems highly variable. Many "good non contest nights" I work
> more EU than in a stew.
>
> I would put reversibility high on your list because you could potentially
> pick up more points from LP or QRP stations to the west, than from EU.
>
> I myself hope to get my array of Two phased K9AYs back together.
>
> Tim N3QE
>
> Sent from my iPhone
>
> > On Dec 5, 2016, at 12:26 PM, Matt Murphy <m...@nq6n.com> wrote:
> >
> > In preparation for the Stew I'm going to attempt to put up a small end
> fire
> > array aimed at EU on my small suburban lot.  There are a large number of
> > books and articles about this topic, but my short-term goal is to build
> > something simple that I can improve upon over the winter as time allows.
> >
> > I do not need the array to be switchable, since most of the points I'm
> > likely to get would come from EU.
> >
> > I was thinking about creating three short verticals along the lines of
> the
> > YCCC receive array (with active coupling) or using the W8JI recommended
> > method with passive components.
> >
> > What approach to phasing makes the most sense given my simple
> requirements?
> >  Advice on spacing?  What's the recommended approach to modeling a system
> > like this to test subtle variations in phasing and spacing?
> >
> > 73,
> > Matt NQ6N
> > _
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Topband: advice on simple end fire array

[Matt Murphy]

In preparation for the Stew I'm going to attempt to put up a small end fire
array aimed at EU on my small suburban lot.  There are a large number of
books and articles about this topic, but my short-term goal is to build
something simple that I can improve upon over the winter as time allows.

I do not need the array to be switchable, since most of the points I'm
likely to get would come from EU.

I was thinking about creating three short verticals along the lines of the
YCCC receive array (with active coupling) or using the W8JI recommended
method with passive components.

What approach to phasing makes the most sense given my simple requirements?
  Advice on spacing?  What's the recommended approach to modeling a system
like this to test subtle variations in phasing and spacing?

73,
Matt NQ6N
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Re: Topband: Soldering radials?

[Matt Murphy]

Is there any danger of damaging stranded copper wire by overheating it with
a torch when soldering or brazing?

73,
Matt NQ6N

On Wed, Oct 12, 2016 at 2:41 PM, Drew Vonada-Smith  wrote:

> Radials are a lot of work to put in, and the expense of wire is
> significant.  I can't see any justification for not joining them the best
> way available.  IMHO, silver brazing.
>
>
> I use and recommend Sta-Silv 15 (15% Ag, 80%Cu, 5% P brazing stick) and a
> simple MAPP gas torch.  Propane is not quite hot enough to work well.
> Liquidus is 1475F.  Flux didn't seem necessary, but you could use white
> brazing flux.  Sure, I spent $25 in solder over about 5 verticals, but of
> what significance is that compared to the rest of the effort, to insure a
> lasting joint?
>
>
> Sta-Silv 5 is probably fine also, with a 1500F liquidus,  But I prefer the
> characteristics of the 15%.  Very easy to work with.
>
>
> 73,
> Drew K3PA
>
>
>
> --
>
> Message: 5
> Date: Wed, 12 Oct 2016 08:52:40 -0700
> From: "Richard (Rick) Karlquist" 
> To: "Topband@contesting.com" 
> Subject: Topband: Soldering radials?
> Message-ID: 
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> I'd like to get the latest thinking from the group
> on soldering radials.  What I currently thinking
> is as follows:
>
> SOLDER SELECTION:
>
> 1.  Tin lead doesn't hold up in the weather.
>
> 2.  "Stay Brite" 3% silver solder (97% tin,
> no lead) is known to work well, but is expensive,
> and has a considerably higher melting point
> than 63/37.
>
> 3.  Lead free plumber's solder obviously works
> in water pipes, but does it hold up outdoors
> in the rain?  What is the melting point?
>
> FLUX SELECTION:
>
> 1.  Pure rosin.  Hardest to work with, but minimum
> corrosion issues.
>
> 2.  Activated rosin.  Easier to work with.  What
> corrosion issues are there?
>
> 3.  Acid core plumber's flux.  Very easy to work
> with, very corrosive.  Does this hold up in the
> rain, etc?
>
> (I remember the dire warnings that Heathkit manuals
> had about not using acid core solder, but I
> guess that doesn't apply to radials.)
>
> CRIMPING?
>
> Has anyone tried crimping as an alternative to solder?
>
> Rick
> N6RK
>
>
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Re: Topband: Handheld Impedance Analyzer

[Matt Murphy]

I recently purchased an MFJ 225 two port handheld mini VNA for $269.

http://www.mfjenterprises.com/Product.php?productid=MFJ-225

I do not own more expensive gear to test its calibration against, but so
far it appears accurate both for measuring Xl and Xc, SWR and also doing
frequency sweeps for testing filters.

I'd vowed not to buy another MFJ product after my 259B turned out to have a
faulty tuning capacitor, but this one seems to have improved build quality
and uses encoders behind the knobs.

The unit is compatible with the IG-miniVNA software which runs under
Windows.  At some point once I have a chance to verify the unit's
calibration I will post a review. My needs at this time are mostly to learn
how to use a two-port VNA and potentially justify the purchase of a higher
quality unit.

73,
Matt NQ6N


On Mon, Mar 28, 2016 at 11:14 AM, Jim Brown 
wrote:

> On Mon,3/28/2016 4:37 AM, KE1F Lou wrote:
>
>> Is the lowest SWR is the resonant frequency?
>>  Resonant frequency is when Xl=Xc.
>> When Xl=Xc is not necessarily the lowest SWR.
>>
>
> Exactly right. If, for example, the antenna's feedpoint impedance at
> resonance is different from the feedline impedance, or if the analyzer
> impedance does not match the feedline impedance, the lowest MEASURED SWR
> will be different from the resonant frequency. This happens with lots of
> antennas, including most dipoles, and with most ground-mounted verticals.
> For example, this causes the minimum SWRof my 80 dipole,as measured in the
> shack by a 50 ohm analyzer, to be about 100 kHz below its actual resonant
> frequency.
>
> This is why swept impedance measurements made by an instrument that can
> produce a file that can be transformed by "subtracting out the feedline" is
> so important.
>
> The feedpoint Z of my high dipoles for 80 and 40 is in the range of 85
> ohms, so I feed them with RG11. This minimizes the ACTUAL SWR in the
> feedline (because SWR is determined by the LOAD, NOT the match to the
> transmitter), so it minimizes feedline loss. It does, of course, require
> matching to the rig or power amp in the shack so that the output stage is
> happy, and to minimize distortion in the output stage.
>
> 73, Jim K9YC
>
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Re: Topband: Spring Stew Perry

[Matt Murphy]

Eric, you were 20 over S9 in Illinois.

On Sun, Mar 13, 2016 at 5:16 PM,  wrote:

> You had a pretty strong signal here for only 11 watts.  Thanks
> for the QSO Eric!
>
> Charlie, N0TT
> OP:  W0CW   EM29
>
> On Sat, 12 Mar 2016 18:58:40 -0500 Eric NO3M  writes:
> > Hand keying with an old bug oscillator HV supply also rectified
> > with
> > a Slop Jar bank (ie. electrolytic rectifiers).
> >
> > Will get a late start; couple hour drive from home yet.
> >
> > 73 Eric NO3M
> >
> > On 2016.03.12 15:59, Art Snapper wrote:
> > > So is that MOPA interfaced to N1MM+ for keying?
> >
> > _
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> >
>
>
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Re: Topband: RFI - and lots of it

[Matt Murphy]

I'm in the process of setting up my station in a new QTH and plan to
install a station ground at the cable entrance.

Tom, is there a best practice for bonding to the mains ground? Any
approaches to avoid?

73,
Matt NQ6N

On Thu, Oct 29, 2015 at 7:07 AM, Tom W8JI  wrote:

> I have and electrician coming next week who says he will check things out
>> and first of all ground the breaker panel to two ground rods 7 feet apart.
>> I thought the grounding was put at the meter but he says they don't do that
>> anymore. I think the old meter, before we had the new one put in had a
>> ground rod beneath it but nothing now. The only ground I could find to the
>> panel is a skimpy wire going to a water line. All of which looks corroded
>> etc.. I know many dollars were spent on renovation and restoration of this
>> place but I'm afraid to much emphasis was placed on cosmetic and not enough
>> on electrical as I look more closely, pretty depressing. >
>>
>
> Jim,
>
> Just keep in mind when  you do the work, the quality of the house ground
> to earth is far less important than having everything entering the house
> being bonded to act like one common point.
>
> One of the biggest mistakes in amateur radio grounding over the decades
> has been having the shack antenna and control cable entrance ground
> non-existent, and the common shack desk equipment ground to an independent
> ground.
>
> The shack ground must be bonded to the mains ground so everything entering
> the house is as close to one potential as you can get it.
>
> Correcting things may not cure your RFI, but it always makes things much
> safer and more reliable.
>
> 73 Tom
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Re: Topband: Use of Remote Receivers During 160 Meter Contests

[Matt Murphy]

In my opinion the stew perry rule is in the spirit of contesting.
Technically advanced stations might all be able to squeeze out a few more
db of SNR yet there are limits and importantly the rule doesn't create an
arms race for a single prime location.

I don't think we necessarily understand the propagation well enough to know
what QSOs might be possible if RX grids could be set up close to but not
necessarily on station property.

W6 big guns are heard all over Europe but Qs can be challenging. There is
definitely room in the sport for RX rules that encourage creativity and
engineering.

73
Matt NQ6N



On Sunday, March 15, 2015, Wayne Kline w...@hotmail.com wrote:

  W2GD's so eloquently  expressed his feelings and I am 100% in
 agreement with him on this issue.

 Ever since John AA1K gave a program at an FRC meeting in the early 80's  I
 have been  tweeking my

 battle with SN/ratio's   and man made nose. hours and hours, beverages,
 bogs K9AY and 4 sq receiving

 array  and  every  wire  every ground rod , was located @  MY QTH 
  no my mountain HOME

  This remote receiving is akin to the days we had a 2mter spotting
 NET. both simples and full duplex.

  some one would call out a station  i.e.  BY9QH  3539and for the un
 believer's  after a  few I can't hear him 

 The call out station would  open hi FM mic to his R4C receiver  and  most
 of use  would be more determined  to

 RE Read ON4UN's low band DX'ing  to see what  we might be able to do.

 I was there when W2GD worked a VU on the top band ... with this CRAZY
 notion promoting remote receive sites.

 I should have keep calling and listing to  keep his  2mtr mic open and
 pray


 My  .02

 Wayne   W3EA



 
 
 
 
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Re: Topband: Brave New World

[Matt Murphy]

I just ordered a remoterig control box to allow my K3 to control remote
stations.  I'm not currently able to set up much of a station and so
looking forward to being able to operate in more contests using remote
stations.  With two young kids my wife is less than thrilled at the idea of
me being gone for a 48 hour multi so this is a great enhancement to the
hobby.

What I like best is that it keeps the spirit of building a competitive
station but lets people share in it who would normally just not operate.
Since I'm not a DXer I don't have an opinion on whether it should count for
DXCC credit.

73,
Matt NQ6N/9

On Wed, Feb 25, 2015 at 3:13 PM, Dave Blaschke, w5un w...@wt.net wrote:

 This is just the beginning!

 Dave, W5UN


 On 2/25/2015 9:05 PM, Eddy Swynar wrote:

 Hi Guys,

 I am really  truly surprised that nobody here has raised so much as even
 an eyebrow at this story:

 http://www.arrl.org/news/no-one-in-the-shack-as-station-
 logs-4200-contacts-in-arrl-dx-cw-contest

 The whole notion---to me, at any rate---compromises the very essence 
 the ...joie de vivre! of operating on 160-meters, don't you think...? And
 to imagine that one of the perpetrators in all this is actually exuberant
 about his accomplishment...

 “...'No one was in the K4VV shack for the entire contest!' said Mike L*,
 W0**, who took part in the contest via K4** from his own shack in
 Virginia...

 This too is progress...? Oh well, I guess maybe it is. Time marches on,
 things evolve, things de-evolve,  nothing stays quite the same.

 ~73~ de Eddy VE3CUI - VE3XZ
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Re: Topband: REVERSE BEACON

[Matt Murphy]

Yes, there is a section on the reversebeacon.net website where you can
download data files with all the historical spots.

http://www.reversebeacon.net/raw_data/

Matt NQ6N


On Wed, Nov 28, 2012 at 8:16 PM, wa3...@comcast.net wrote:



 I am planning a new 160m transmit antenna to be erected in the next few
 weeks.  Before I install it however I want to get a good history (over a
 few weeks) of spots from the reverse beacon network.  My problem is that
 instead of going to WWW.DXMAPS.COM   I would like to get the spots from
 the source.  Is this possible?  Is there a utility/program out there that
 will allow me to plug my call into it and collect all of my spots for me...
 displaying them on my computer ready to be archived/plotted.. whatever?



 My new antenna will be a 75 ft Vertical elevated about 8 ft above
 the ground to include 20 1/4 wave radials.  This should be superior to my
 current Inverted L with 4 radials 6 ft above the ground that the deer keep
 getting into.



 WA3MEJ


 Long Live Seal Team VI

 http://www.qsl.net/wa3mej/index.htm
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