[evlatests] Antenna 21 at K-band

[Rick Perley]

Ken took 80 minutes of K-band data yesterday afternoon, around 4PM. 

All EVLA antennas, except 23 which was stowed for Q-band work (I think), 
fringed -- including antenna 21. 

But antenna 21 is clearly 'special' -- the amplitudes started of very 
weak -- about a factor of 10 below normal, then steadily rose, reaching 
normal levels about 35 minutes after the start, then steadily declined, 
ending up about a factor of 2 below what they should be. 

A pointing problem is possible -- the elevation of the beginning was 72 
degrees (HA of +1.5 hours), with steady decrease to 58 degrees at the 
end of the run.   But the factor-of-ten loss (100 in power) indicates a 
large offset of an arcminute or so -- which would not be sufficient to 
cause the X-band data to be lost (in an earlier run), unless the 
pointing then was much worse.