[evlatests] RFI birdie in Ka-band

[Ken Sowinski]

On Thu, 17 Aug 2023, Rick Perley via evlatests wrote:

> I find a fairly strong 'birdie' in Ka-band -- at 30.976 GHz. This is the 
> 242nd multiple of 128 MHz.  Don't know if this is relevant ...

This was in 23A-317 observed on July 17, 2023 using

      LoIfSetup(True,"33GHz",37500,35500,33500,31500,1)

Which resulted in an L301-1 setting of 15498 MHz, the second harmonic
of which is 30976 MHz.

We have previously seen such birtdies in Ka band with a variety
of tunings; some of them much stronger than this one.  I don't
know if anyone was able to show whether it was really the second
harmonic getting into the RF, or some other path with the same
outcome.

Ken