[evlatests] JVLA Tests Meeting -- this Thursday, 10AM, Rm 317

[Rick Perley]

     We have (so far) four topics for the upcoming 'tests' meeting:

     1) Saving your science when 'Set and Remember Fails' (for any 
reason).  (Rick)

           Under some circumstances, 'set and remember' will fail, 
leaving the system to attempt to auto-set the powers for each scan.  
This *should* result in a more-or-less constant power to the samplers.  
For reasons unclear, this fails -- sometimes badly.  The only recourse 
is to utilize the switched power.  This works -- *spectacularly well* -- 
for the 8-bit samplers.  I'll show the evidence, and we'll discuss what 
is to be done.  We may be able to include the 3-bit system in the 
discussion.

     2) Artificially induced antenna gain-elevation effects. (Rick)

         The antenna elevation gains have been remeasured. Strong 
evidence that we are artificially inducing a strong elevation gain 
dependency at Ku-band (and perhaps at K-band also) will be shown.  The 
cause is almost certainly due to incorrect coefficients in the 
'subreflector rotation trick'.  The results match the tests done by my 
summer student last year.  With his return this year, I expect we'll 
finally put this issue to rest.

     3) P-band collimation for the JVLA.  (Ken).

     Ken will discuss how we failed to implement any collimation 
corrections at P-band for the JVLA, the results of new measurements, and 
various options for future implementation.

     4) Correlation of Switched Total Power with Observed Phase at 
K-band.  (Vivek and Eric).

     Vivek will summarize results from his ongoing study.

     Rick