[evlatests] Still more on Switched power -- L-band

[Rick Perley]

    Perusal of the L-band data show some further oddities, not seen at 
the other bands ...

    Antenna 9 has a Pdif ~ 0.  (All IFs).

    Antenna 18 has large and quasi-random Tsys values (due to Pdif 
variances), but only on Cyg A, and only in RCP.

    Antenna 28, in LCP, shows most of the values with wild variations. 

    In general, many, but certainly not all, antenna-IFs show far 
greater variances in the 1-second determinations of Tsys (from Pdif) 
than others.  I'll try make some sense of these a little later.