[evlatests] EVLA L-band tuning failures

[Rick Perley]

    I ran a challenging experiment on Sunday.  The goal was to determine 
the
L-band sensitivities as a function of both frequency and elevation.  
Doing this
required observing 14 separate frequencies, covering the entire plausible
tuning range permitted by the VLA OMT (also on the EVLA antennas) --
1275 to 1750 MHz.    I used 'mode 4', so 7 of these 14 were tuned by the
'AC' IFs, the others in 'BD'. 

    The EVLA antennas successful tuned to 11 of these 14 frequencies.  For
the other three, none of the 3 EVLA antennas provided any data.  The
failed frequencies are:  1590, 1670, and 1370 MHz.  All three were 'BD'
frequencies.    As I cycled around and around the 7 frequency pairs, the
failures above are systemic -- they failed every time. 

    There was one other interesting failure in the experiment:  The executor
apparently 'froze' on the first source, while the VLA antenna moved on with
the program.  The operator aborted the EVLA script, then restarted.  All
proceded normally after that. 

    Other than the above problems, all the data appear to be of outstanding
quality (other than RFI in some of the frequencies I chose).   I have 14
different databases to reduce, (actually, 11, due to the tuning failures 
noted
above) so the results of this test will not be available until later 
today.