[Elecraft] K3 diversity phase drift

[Jim Brown]

On 4/8/2026 1:42 PM, David Gilbert via Elecraft wrote:
> It's not really even a deal breaker for my arrival angle application 
> since in my tests I'm seeing LOTS of other weird effects that have a 
> much greater effect and at this point appear to be due to various 
> multipath phenomena ... some obviously due to propagation but also 
> apparently due to near field ground reflections as well as more distant 
> terrain reflections.

In applications like this, it's important to remember that the phase 
shift between diversity antennas is the result of both their spacial 
orientation AND the time difference between wavefronts that have taken 
different paths. That time difference is what causes what we call the 
slow "selective fading" at LF and MF, and "picket fencing" at VHF. And 
because the phase shift resulting from a time difference is also a 
function of frequency, deep fading (strong cancellation) occurs at 
different times at different frequencies.

73, Jim K9YC