[evlatests] Phases on antennas 14 and 24

[Rick Perley]

    I reported yesterday on phase changes seen on two EVLA antennas 
during the 'modcomp-free' tests last Friday. 

    To Recap:

    14B and D showed two alternating phase states, separated by about 40 
degrees. 
    24, all IFs, showed multiple phase states. 

    For both antennas, phases are stable within any phase state.  The 
transitions are abrupt, but always are such that an intermediate phase, 
exactly halfway between the two, is seen.  Hence, the cause must be 
linked to the fundamental integration time -- 0.417 seconds. 

    Vivek reported that likelihood that antenna 24's behavior was likely 
due to a misbehaving RT phase.  Ken disabled this meter. 

    Data taken today, with Modcomps in control, show:

    Antenna 24 now has stable phase. 

    Antenna 14, IFs B and D are behaving as reported above. 

    Upon review, the following additional characteristics are seen on 14 
B and 14 D:

    The transition always takes place following a 10-second 'tic'.  The 
duration of the alternate phase is always 10.0, or in rare 
circumstances, 20.0 seconds.  The two IFs always jump together, by equal 
amounts.