[evlatests] Antenna 21A has issues ...

[Rick Perley]

    In the test run described in the last email, I note that antenna 21, 
in IF 'A', is commonly slow to 'lock up' and give fringes.  At L, C, and 
X bands (antenna 21 doesn't have an S-band receiver), this IF, alone, 
often took a minute or more to give good fringes.  The problem does not 
happen at all band changes, but is notably more prevalent when switching 
to X-band (from C-band): 

    From X to L-band:  2 of 7 scans were affected
    From S to C-band:  2 of 6 scans were affected
    From C to X-band:  all 6 scans were affected. 

    As implied above, the other IFs for this antenna were not affected 
-- they fringed quickly, along with all other antennas.