[evlatests] L-Band Performance at noon

[Rick Perley]

    During Ken's lunch hour, I ran L-band to check on system 
performance, and confirm the claimed sensitivity loss with cold-sky 
observations. 
    Six frequencies, spanning L-band from 1275 through 1706 MHz, were 
chosen. 

    All four L-band-equipped EVLA antennas (13, 14, 16 and 18) are 
performing magnificently.  There are no dropouts (seen with 3.3 second 
averging) visible on any antenna, IF, or frequency.  None of the sudden 
phase changes reported by Michael Rupen on 13 were seen.  The phase on 
EVLA baseline 13-18 continues across frequency changes. 
   
    Items of concern:

    Antenna 14, IFs C and D, gave very weak fringes at 1670 and 1706 MHz 
(respectively). 

    Antenna 18, IF D, is returning Tsys values that do not reflect 
reality.  (The other IFs are fine).  

    All antennas show the now-familiar pattern of loss of sensitivity 
with increasing frequency, as judged by AIPS weights.  

    Unfortunately, a blunder on my part resulted in no useful 'cold sky' 
data from which to directly determine the system sensitivity.  I'll try 
recover these observations later today.