[evlatests] Phase Step Problem is a Hoax!

[Rick Perley]

    I reported yesterday about a curious -- and worrisome -- apparent 
problem with the phases, seen in the X-band 'Herc A' data.   Phases on 
some many antennas appeared to step by 45 or 90 degrees each time we 
returned to the same calibrator at the same band, after having cycled 
through three other bands over 10 minutes. 

    It's not real.  The effect has been introduced by the calibration 
software, but I cannot understand how.  The phase step is introduced by 
CLCAL when applying the delays solutions.  But although I have solved 
for the delays using only 3C286, and have asked for 90-hour smoothing of 
all solutions (meaning both phases and delays) to ensure that only a 
single value is actually applied, I find that the reported phase steps 
have been introduced *on the target sources only* by the calibration.  
Something is not working in the intended manner! 

    Some consultation with experts is needed.