That's the key - non-resonant dipoles.
There's a lot of advantages to "physically small" antennas in receive
applications - especially since the atmospheric and other noise tends to
dominate, so the loss in sensitivity from a shorter antenna doesn't affect you.
Reduction in mutual coupling is but one.
On Fri, 10 Apr 2026 10:46:55 -0700, David Gilbert via TowerTalk
<towertalk@contesting.com> wrote:
Thanks, Stan.
Well, the dipoles are purposely short ... only 10 feet long ... and
since they aren't even close to being resonant at 15 MHz the idea was
that any coupling would be minimal. I modeled broadside dipoles using
EZNEC and the results for phase difference versus elevation tracked the
separately calculated values literally to a couple of tenths of a
degree, so that showed no coupling effects.
Besides, the test run I did with the drone didn't show any obvious
coupling effects that I could discern. The ground effects seemed far
greater.
And while end-to-end dipoles would probably work OK (although I think
verticals would be better) for azimuth, I don't think they would work as
well for elevation. In any case, I don't have the structures available
to point a rope at WWV.
73,
Dave AB7E
On 4/10/2026 3:51 AM, Stan Stockton wrote:
> Very impressive work, Dave! Doesn’t matter if AI wrote the code. You were the
> brains behind it.
>
> When I first read your post I thought perhaps you were going to use a couple
> of dipoles end to end with rope between them for the antenna and was
> surprised to see the dipoles on a boom. Would that not present some problem
> with the coupling between those dipoles in the same plane with one behind the
> other?
>
> 73…Stan, K5GO
>
>> On Apr 10, 2026, at 2:11 AM, David Gilbert via TowerTalk wrote:
>>
>>
>> Not too long ago I mentioned that I was working on a application that would
>> hopefully measure and display the arrival angle of an RF signal by feeding
>> the audio from two phase locked receivers into the sound card of a computer
>> and doing the processing on a browser web page. The application is now
>> functional and I have created a YouTube video describing what I tried to do,
>> how the application works, and to what degree I was successful. At 50
>> minutes it's pretty long so if you decide to watch it you might want to
>> click on the YouTube settings icon at the lower right to speed it up. My
>> production skills are limited so please take that into account.
>>
>> The YouTube video is here:
>>
>> https://youtu.be/MxRaYSRMPE4
>>
>> The actual application is here:
>>
>> http://www.ab7e.com/ArrivalAngle.html
>>
>> You can run the app directly from my web page but you can also just download
>> it (right-click, save page as .html) and run it locally on your own
>> computer. It's totally free and comes with no guarantees of literally
>> anything.
>>
>> I'd appreciate any comments or suggestions, and I'll try to answer questions.
>>
>> 73,
>> Dave AB7E
>>
>> p.s. The application was written by OpenAI's Codex coding agent. I created
>> the layout and the prompts that specified how it should work, and I did a
>> lot of refining, but I didn't write a single byte of the actual code. We're
>> in a new era of custom software for almost any use no matter how limited the
>> audience may be for it.
>>
>> _______________________________________________
>>
>>
>>
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