[evlatests] P-Band

[Jim Jackson]

We've determined that the interference in P-band on the VLA and EVLA 
antennas is indeed coming from Antenna 13.  It goes away when the 4/P 
band receivers in Antenna 13 are powered down but troubleshooting and 
even replacing the receiver has not identified the problem.  The 
receiver in Antenna 1 also does not work and exhibits the same 
oscillatory spectrum in the bandpass plots as Antenna 13, though it 
does not seem to interfere with the other antennas like 13.

We have disconnected power from P-band in both Antennas 1 and 13 so 
P-band should be functioning for observation on the rest of the array 
over the weekend (excluding Ant 16 of course). This is really bizarre 
behavior - Chuck, Rob and I plan to go to the site to dig into this 
early next week.

Jim