[evlatests] C-Band results

[Rick Perley]

    Following perusal of yesterday's C-band data:

    1) Two 180 degree phase flips, as noted by Michael.  These occurred 
at 22:11:48, and 22:23:08 (my time resolution is +/- 1 second). 

    2) Today's delays are, in nsec, referenced to antenna 2:

    1         29.3
    3         70.3
    9          -1.6
    18        12.7
    19          9.5
    23          2.3
    24         5.2
    25          no signal
    28         10.5

    All of these are the same as the X-band values from Saturday, 
*except* antenna 3, which went from -9.8 nsec to +70.3.  What happened?
    Antenna 25 has been moved (as noted by others), and no coherence was 
obtained. 

    3) Antenna 2's correlation values declined steadily throughout, and 
suffered two large (tens of percent) discontinuous drops, in both IFs.  
The drops did not correspond to the phase flip times. 

    4) There are two, and only two, baselines showing sinusoidal 
phases:  2 X 19, and 24 X 19.   The amplitudes look normal on both 
baselines. 
       For 2 x 19:  Oscillation period at beginning (22:05 IAT) was 3.5 
seconds, with amplitude 4 degrees (pk-pk).  At end of run (22:30), the 
period had shortened to 2.6 seconds, and the amplitude declined to 2 
degrees.
       For 24 x 19:  Oscillation period at beginning was 6 second, with 
amplitude 3 deg.  At end, period was 3 seconds, with amplitude 2 degrees.
    Antenna 2 is at E2, antenna 19 at W4, antenna 24 at W14.  It's hard 
to find any geometric origin for what we are seeing. 

    Imaging of the two sources observed (3C84 and 3C273) is not useful 
-- both are significantly resolved.