[evlatests] C-Band Switched DAta

[Rick Perley]

    Same experiment as described earlier.  Cygnus A at 6cm doubles the 
system temperature.

    About half the antennas show neither a zero offset (when switched 
power is turned off), nor PDif compression when observing Cygnus A.  The 
other half show varying degrees of the following:

    A) Most show PDif compression, typically a few percent, but as large 
as 30% for antenna 24 in RCP. 
    B) Some show PDif *expansion* -- antennas 2, 4, and 28 do this in 
some of their IFs.
    C) Most antennas with compression or expansion also show zero 
offsets with the switched power turned off.  It seems to be true that 
the 'expanded' antennas show positive offset, and the compressed 
antennas show a negative offset. 

    As noted for the other bands, some antenna-IFs show power levels far 
from where they should be -- by up to a factor of 10 ...