[evlatests] WIDAR-0 Phase Hoppers

[Rick Perley]

    The 4.5 hour run from last night (37.7 GB) is filled with phase 
jumps, with the now-familiar characteristics that I list below:

    o  The phase change is exactly 180 degrees.
    o  The same 5 antennas show it:  1, 3, 9, 23 and 25.  The 
'non-hopping' antennas are 2, 18, 19, 24 and 28. 

    In this run, we have 23 phase hops.  None are seen within a scan, so 
there is strong evidence that this phenomenon only occurs on scan 
boundaries.  (This is not conclusive -- about half the observations are 
on blank sky, and on about half of these, the phase hopped between the 
preceding and following calibrator.) 

    The phase hops transitions are not uniformly distributed in time -- 
unlike the previous two tests which indicated a predictable interval. 

    This is a very important problem to repair -- it's hard to do 
science with this phenomenon in place!