[evlatests] 'Holography' phase jumps, continued.

[Rick Perley]

    The dataset referenced in the previous message shows interesting 
phase behavior. 

    The three BW/Fluke setups were:

    BW = 50, Flukes = 100, 200. 

    BW = 25, Flukes = 112.5, 212.5

    BW = 12.5, Flukes = 118.75, 218.75. 

    The results for phase stability are:

    1) For BW = 50, there were no phase jumps of any kind. 

    2) For BW = 25, there was a single *global* phase jump, affecting 
all EVLA antennas (using a VLA antenna as reference), and all IFs 
equally.  The jump was 125 degrees for all IFs.  The jumps was 
effectively instantaneous -- duration less than 0.4 seconds. 

    3) For BW = 12.5, we had three *global* phase jumps, affecting all 
EVLA antennas equally in all IFs.  But in this case, the jumps were all  
by *precisely* 180 degrees.   Again, all jumps were effectively 
instantaneous -- much shorter than the 0.417 second integration time. 

    It is noteworthy that there were *no* 10-second style phase jumps, 
that plagued us last summer. 

    There is no way to tell from these data whether the jumps were in 
the VLA, or the EVLA. 

    Question:  Can we do holography yet with an EVLA reference antenna?  
If we have only these global jumps, I can proceed with holography, using 
an EVLA reference.