[evlatests] Some Results from Switched Power

[Rick Perley]

    I ran two short test files yesterday, one to look at the sun and 
some calibrators (in OSRO mode) at  L and S bands, the other to test 
RSRO modes in C and X bands. 

    I have reviewed the total and switched power from these, and a few 
notable items are worthy of mention:

    1) Antennas 10 and 24 gave no switched power (values are noise) at 
any band, but gave good total power at all bands. 
    2) At Sband, antenna 22 gave no fringes, nor any sensible switched 
or total power -- there is supposed to be a receiver in that antenna, 
but we got no sensible data from it. 
    3) Antenna 12, at S-band, gave no switched power (noise), but gave 
good total power.
    4) Antenna 6, in RCP only, provided variable switched power on the 
calibrator, and completely random values when on Cyg A (system 
temperature approximately doubled).  It was o.k. in LCP. 
    5) At Xband only, the ratio of Psum/Pdif is much higher for antennas 
16 and 22 than any others.  For the others, a value of 10 -- 20 is 
normal.  But for ant 16 the ratio is 50 in RCP and 110 in LCP, and for 
ant 22 the ratios are 75 in RCP and 60 in LCP.  Either the Tsys values 
for these antennas are much too high, or the Pcals are much too low ...

    Further tests, with a better setup, will be done this afternoon at 
L, S, C, and X bands.