[evlatests] P-band polarization reversals

[Paul Harden]

On 9/4/2013 2:39 PM, Rick Perley wrote:
>      A fair chunk of P-band data was taken last night.  All antennas in
> the array fringed, except for ea19, which has no receiver.

EA19 apex barrel is still being repaired.  Next Monday (9/9), Dan and I 
hope to get the receiver back into EA19, and do the final receiver 
install on EA21 on the master pad to complete the array.

> ea01 and ea09 may not be simple -- they both
> have very high cross-polarization -- nearing 50%

Receivers in EA09 and 25 will be brought back probably next week, as 
these have very high 4-band gain and high Tcals that need to be properly 
set.  We will check dipole orientation when we do this, and I will check 
the isolation between polarization channels while the receivers are in 
the lab.  Isolation between X/LCP and Y/RCP is usually 50dB or better in 
the receivers.

Maybe we need to take a drive down the arms to check P-band orientation 
on all antennas.  You can see gross misalignment from ground level when 
antennas are stowed.

Paul