[evlatests] L-band on antennas 21 and 16

[Rick Perley]

    Contrary to my earlier report, antenna 21 does fringe well at 
L-band.  The sensitivity was down by perhaps 25% compared to average 
antennas.  Ken reports that the operators have tweaked up delay and 
focus, so perhaps this afternoon, all will be well.

    Antenna 16 also gave fringes at L-band, but its sensitivity is way 
below what it should be -- down by a factor of three at least.  And IF 
'C' is completely broken.