[evlatests] P-Band situation

[Rick Perley]

    I'm confused as to the state of the P-band system.   Perhaps 
somebody can clarify what is on the antennas, and what isn't...

    I ran a short observation yesterday afternoon, to see what worked, 
and what didn't. 

    1) All data from 11, 13, and 16 are flagged out.  But when I fill 
the data with the flags ignored, I see stable (but usually weak) fringes 
on most of the IFs from these antennas.  Looking at EVLA Antennas 
Modifications/Retrofits sheet, I note that receivers are claimed to be 
in all three antennas -- but boldfaced for all three.  What does this 
mean?   Which of these antennas should (or could) give fringes, and 
which should not? 

    2) Antenna 4, IFs A and B are very erratic and weak.  A is not 
flagged, but B is.    IFs C and D are fine. 

    3) Antenna 26, IFs B and D (IF#2) gives no fringes, but is not 
flagged.   IFs A and C are fine. 

    4) Antenna 17, IFs B and D, gives good fringes, but is flagged.    
IFs A and C are fine. 

    5) Antenna 21, all IFs, has large, semi-square wave, amplitude 
pulsations of very large amplitude.  The phases seem not to be affected 
by this.  I recall noting this same effect some weeks ago...