[evlatests] Ka-Band S/N 2 on Antenna 2

[Bob Hayward]

Glad to hear it is alive.

On the polarizations being swapped, I was a bit puzzled to find that if 
I disabled the LNA's on the RCP side, the detected output on the LCP 
channel would drop. And vice versa. I was hoping it was just a mix up in 
the harness carrying the bias voltages to the amps and not a cross in 
the RF signals. Looks like it is the latter. My guess is that the 
phase-shifter might be rotated by 90 degrees from the desired 
orientation. I think the output path after the amps is OK (since its not 
easy to cross the WR-28 waveguide runs).

For the time being, we'll swap the RCP & LCP cables at the outputs of 
the receiver when we get a chance...

-Bob


Ken Sowinski wrote:
> It works fine even if it is a bit hot.  Focus and pointing
> are pretty close and there is a respectable fringe amplitude.
> Delays have been set relative to antenna 4.
> 
> But...  ea02 has its polarizations swapped compared to ea04.
> I would argue that ea04 is correct because if has fringed
> with the other antennas at K and Q bands.
>