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

[Ed Fomalont]

It's me again.

    There is no doubt that the EVLA phase behavior is worse than the VLA 
phase behavior.  As far as I can tell, the EVLA antennas appear to have 
changes between 0 to 60 degrees between calibrator scans that are 
separated by 30 minutes.  Changes for VLA baselines are usually less 
than about 5 to 10 deg.  Over the 2-min calibrator scan there are no 
noticeable jumps or phase gradients.  The amplitude stability looks 
pretty good.  These 'jumps' don't appear to be geometric but come and 
go. for the various EVLA antennas.  Even using an EVLA reference 
antenna, the phase stability to other EVLA antennas is not particular 
good and inconsistent among antennas and time.


Ed