[evlatests] Antenna 18

[Rob Long]

Antenna 18 has good switched power on K and Q-bands as of this 
afternoon.  We found two coax cables in the fan section of the U/X 
converter with broken shields.  The main culprit was more than likely 
the LO input cable.  It was actually allowing the resonance of the DC 
fans to couple into the signal path at 309.5 Hz and 315 Hz.  (Two fans 
in the enclosure!)  All four cables in this section of the converter 
were replaced and signals now look good at the T-5s (all IFs).

There is also a C-band receiver installed in ant. 18 and cooling down. 
Once we have verified signal quality to the T-5, it should be usable.

Rob