[evlatests] AM889 observation now on the EVLA: EVLA PHASES!!

[Ed Fomalont]

Okay, more information.

Using antenna 9 as reference (a nice VLA antenna), the phases for almost 
all of the EVLA antennas have the following property:

Phase difference IF 2 - IF 1: Stokes 'R'

   From 13:30 to 15:30 there is a phase gradient of 40 deg over the two 
hours.

   The phase difference then resets to the 13:30 value and

   From 15:30 to 17:30 this phase difference repeats.

A phase change of 40 deg between IF's separated by 50 MHz is a lot of 
phase change at each frequency.  (28 times this amount)

Yet, I see no phase drifts over a three-min scan, even in the IF only phase:

Now using an EVLA antennas as reference, most of the other EVLA antennas 
show little phase difference change between IF1 and IF2, although this 
difference appears noiser with a few 5 deg glitches.

GUESS:  The delays, phases set at the beginning of a scan for the EVLA 
antennas are incorrect.  But the tracking of the phase is okay over the 
scan.

Confused,  Ed

No, I'm not smoking anything.