[evlatests] Antenna 21, IF 'A'

[Rick Perley]

    I've noted earlier that antenna 21, IF 'A' is slow to provide 
fringes when a band is changed.   This was based on tests done at L, S, 
C, and X bands. 
    Further testing (for other purposes) shows that (as expected), the 
problem is common to all bands.   The duration of non-fringing is 
variable -- from as short as a few seconds to well over one minute.  No 
other IF is affected. 

    One other signature -- when the fringes are absent, I note that a 
small pulse of fringe power (not of full amplitude) is seen once ever 
ten seconds, always on a time ending in '7' (i.e., at 07, 17, 27, 37, 
etc.) seconds. 
   
    Sounds like a station board issue ...