[evlatests] ea17 subreflector position

[Rick Perley]

     The (very) extensive holography that we've been doing the past 
couple of weeks has revealed a number of issues.

     Perhaps the most outstanding is that the horizontal position of 
ea17's subreflector is more than 10 mm off!  This is huge.  It is seen 
(at the same level) in all four frequency bands that we've utilized:  X, 
Ku, Ka, and Q.  The corresponding phase error on the main reflector is 
big -- over 100 degrees at 41 GHz.