[evlatests] IF 'B' problem, and delays.

[Rick Perley]

    I reported yesterday that at P-band, observing in continuum with 
12.5 MHz BW, the VLA and EVLA were incoherent on cross baselines, but 
o.k. within themselves.

    The problem is now seen to be present in all the spectral line data 
-- all of which was taken at 12.5 MHz BW.  This seems to point pretty 
clearly to a Fluke setup error. 

    In addition, the speculation that the gain odditites seen in antenna 
24 B and D were due to a delay error is confirmed -- the error 
corresponding to a half turn in phase across 50 MHz BW (about 10 nsec).  
Big enough to reduce the amplitude significantly (as observed).  It is 
also found that antenna 13, IFs B and D have a Very Large delay error, 
probably sufficient to reduce the signal to insignificantly low values.
    However, no error in delay was seen for antenna 5, at X-band.