http://elecraft.85.s1.nabble.com/K3-Diversity-Reception-and-Antenna-Directivity-tp5537531p5539032.html
Yes, I think that would work fine. There are two issues that I can
difference between them is random. I believe that if you change
same. So every time you change frequency you may have to re-adjust the
> Several weeks ago, I believe that Wayne posted a message asking what
> kind of different uses people were coming up with for their K3. One
> thing I've been playing with lately is feeding the signals from two
> horizontally polarized antennas at different heights on my tower into
> the Main and Sub receivers of my K3 in diversity mode. Since the
> relative phase between the two signals is preserved in the translation
> to audio, I can feed the audio from the two receivers into the A and B
> channels of my computer sound card and compare the relative phase using
> a dual-trace sound card oscilloscope program like Zelscope. By knowing
> the vertical distance between the two antennas I'm hoping to be able to
> calculate the arrival angle of the signal in real time. I say "hoping
> to" because so far I don't have a distant stable, unmodulated carrier to
> work with ... the best DX carriers have come from 40m BC stations but
> the modulation screws up the triggering. Once I get the methodology
> worked out a bit better I'll ask someone in Europe to throw a carrier on
> frequency for me.
>
> Playing around with this stuff got me thinking, though. What if I fed
> the output from two VERTICAL antennas into the K3 receivers in diversity
> mode, fed the audio output of both receivers into the A and B channels
> of the computer sound card, and used an application that introduced an
> adjustable delay in one audio channel before summing the two channels
> and doing the D/A translation back to monaural audio? Wouldn't that
> have the exact same effect as being able to adjust the phase of the
> incoming RF, and therefore the directivity of the 2 element vertical
> array? I'm pretty sure that today's computers could certainly handle
> the computation. There wouldn't be any constraints on the amount of
> delay so the array should be continuously steerable through an entire
> 360 degrees, and since the delay would be imposed digitally there
> wouldn't be any frequency dependency. Ideally the two feedlines would
> be of equal construction and equal length, but even if they weren't it
> would be fairly easy to characterize their relative phase delay as a
> function of frequency. I think mutual coupling even become a non-issue
> if the verticals are non-resonant. Non-resonant antennas might be the
> way to go anyway since such unlimited control over phase means that
> spacing between them would be less of an issue, and therefore the same
> pair of verticals could be used on more than one band as long as the
> spacing was wide enough.
>
> Why wouldn't this work? The PCM data format is pretty straightforward
> and I can't believe that the application would be that complicated to
> write. I must be missing something but nothing jumps out at me. If it
> worked, it could even be a feature in a next generation K3 (maybe even
> the current one) .... all it would take is some means to adjust the
> delay since everything else (two phase locked receivers, DSP processing
> for both RF and audio) is already there.
>
> In the case of the K3, all of this would only apply to reception, of
> course, although it almost seems like a transceiver could be engineered
> that used the desired delay determined from the receiver to set a
> corresponding delay for two identical tone-modulated transmitter chains
> driven from the same oscillator. I suspect a pair of phased
> transmitters would have pretty limited appeal, though ... certainly
> they'd be an expensive way to get just two or three db steerable gain.
>
> Fun stuff to think about, in any case.
>
> 73,
> Dave AB7E
>
>
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