[evlatests] L-band phase drifts

[Rick Perley]

    A more careful review of these remarkable phase drifts:

    A) The drifts are *perfectly* linear in time over the full 6 hours, 
and are independent of source. 

    B) The drifts are identical for each sub-band, for a given antenna. 

    C) The drifts are different for each antenna, and between the two 
polarizations.  The following table gives the one-hour rate for RCP, and 
the difference in the rate between the polarizations (R - L), in 
degrees.  Accuracy is about 1 degree. 

   Ant    ph(R)     ph(R-L)
----------------------------------
    2        -30        +28
    3      +170       +28
    4       -12         -27
    5       +60        +17
    8       +15        +15
    9       +80        +14
    15     +50        +9
    19     +75        +80
    24     +260      -13
    25     +3          +18
    27     -40         +52
    28        Reference
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