[evlatests] Low Band status

[Paul Harden]

Dan and myself worked on the Low Band system on a couple of antennas to 
address issues from the Scientific Staff:

EA13 - NO CAL SWITCHING
Cal switching is present at the apex, but no noise cal happening in the 
receiver.  The receiver was removed to repair the faulty noise source or 
switch.  Hope to repair and reinstall Friday.

NOTE: NO LOW BAND RECEIVER IN EA13 (not a VLITE antenna) at the moment

EA14 - WEIRD BANDPASS SHAPE OR RIPPLE
Verified.  Found a couple of loose SMA connectors where the low band 
signals enters the LO/IF rack at the VLITE power splitters.  Likely 
cause of the ripple.  Bandpass of receiver outputs on spectrum analyzer 
now appear normal, to be verified next low band observing or test.

806 MHz RFI
Report of a fairly strong 806 MHz station in the passband.  Though 
outside of the low band frequency range, this is hugging the 806-814 
radio astronomy band.

This signal could not be seen at the receiver outputs on either EA13 or 
EA14.

Paul