[evlatests] Strange Phase Behavior for ea22

[Rick Perley]

     Beam cuts were taken last night, as part of our optics alignment 
program.    Bands observed were from X through Q. Stability was 
exceptional (as we might expect on a cold, clear, calm night).

     All antennas behaved exceptionally well, except one.  ea22 has 
phase oscillations many times larger than they should be.

     Ea22 is at W10.  Using ea28 (at W8) as a reference, I compared the 
phase behavior of the baseline ea28 -- ea22 to that of ea28 -- ea26.  
The latter is at W6, so the baselines are of comparable length.  Below 
is a short table, showing the amplitude of the phase fluctations.  These 
were established from the CALIB gains, over the 45 seconds that were 
spent on the four calibrator observations.

     Band             ea26        ea22

-------------------------------------------

     X                    <1            8 degrees

     Ku                    1            15 - 20

     K                     2                15

     Ka                    6                >20

     Q                    4                40 -- 50

-----------------------------------------------------

     Both polarizations behave identically.  The fluctuations scale 
roughly with frequency.  The character of the fluctuations is 
essentially identical to atmospheric -- except they are 10 times too 
large.  No other antenna (even those at the ends of the arms) showed 
fluctuations anywhere near what ea26 has.

     So unless we're willing to believe that the atmosphere is 'special' 
above ea26, and no other, there's something not right with the phase 
tracking for that antenna.