[evlatests] Antenans 14 and 18

[Rick Perley]

    Ken and I ran tests overnight at K and Q bands (tweaking the 
subreflector rotation trick). 

    At both bands:

    a) Antenna 18 gives no sensible fringes (and it may have 'shredded 
levels') in IFs A and C. 

    b) Antenna 14 has two phase states, separated by close to 180 
degrees, on all four IFs.  

    Both phenomena are operating on a timescale shorter than the 1.66 
second integration time we used.   If helpful, we can run a short test 
later this morning, with 0.416 second integration.