[evlatests] Other S-band issues

[Rick Perley]

    Some other things found at S-band:

    1) PDif values from antenna 6 in RCP (both IFs A and B) are wildly 
oscillating by over a factor of two, with no recognizable pattern.  It 
looks like noise, except the values are far higher than noise values -- 
they are not centered about zero, but at a much higher positive value.  
PSum looks fine.  I think this situation has been this way from the 
beginning. 

    2) The system temperatures in LCP for antennas 7 and 27 are far too 
high, near 100K.