[evlatests] May Test Results Meeting, Thursday at 10AM

[Rick Perley]

     All:

     Tomorrow is the 2nd Thursday of the month, hence time for the 
monthly 'test results' meeting.  So that will 10AM, 08 May, in Rm 317.

     There is little new to present, so Keith and I would like to have a 
short meeting to discuss what tests can and should be done over the next 
few months.   The goal is to get a sense of what the priorities should 
be for testing over the summer months.

     We with to limit the discussion to antenna and electronics 
testing.  Specific correlator testing should be discussed separately.

     Some off-the-cuff topics include:

     1) Switched power effectiveness, including 'PDif' and 'PSum' 
issues, and the values of Tcal.
     2) Further 3-bit testing, including methods to correct for the 
large 'PDif' compression that occurs in that mode (and which is probably 
separate from that which affects the 8-bit sampling mode).
     3) Elevation gain functions
     4) Antenna optics -- in particularly the efficacy of the 
'subreflector rotation trick'.   ea15 and ea18 are different than all 
the rest (at present), and ea20 is just plain weird.
     5) Beam holography at L and S bands (and any other band).
     6) Surface holography at P-band (and any other band).
     7) New ACU tests.
     8) Temperature stabilization of the noise diodes.
     9) 5 MHz comb power (at 4-band)

     Please bring your own lists, if different than above.

     Rick



-------- Original Message --------
Subject: 	Re: New EVLA things to worry about: a List
Date: 	Fri, 02 May 2014 14:07:19 -0600
From: 	Keith Morris <kmorris at aoc.nrao.edu>
Organization: 	NRAO
To: 	Ken Sowinski <ksowinsk at nrao.edu>
CC: 	Jim Jackson <jjackson at nrao.edu>, Rick Perley <rperley at nrao.edu>



> Other stuff that comes immediately to mind involves testing/verifying
> yet unused correlator capabilities.  I don't think that is what you
> want for this list.

Do those include "Y1" mode?  Vivek had mentioned doing an ea20-PT
baseline, but I believe it would require an as yet unavailable
correlator mode.



On 5/2/2014 9:56 AM, Ken Sowinski wrote:
> These seem to be mostly 'old' things.
>
> On Fri, 2 May 2014, Keith Morris wrote:
>
>> Here are some of the issues that Rick, Jim and I thought should be on
>> our list of things to worry about:
>>
>> 1. Switched power compression
>> 2. Thermal effects in switched power
>> 3. Polarization phase (and its possible connection to switched power)
>
> I suppose this means that variations in pol phase and switched power
> may have a common cause?
>
>> 4. 3-bit-specific switched power
>> 5. New ACU testing (qualification, specifications, etc)
>> 6. Antenna optics & gain curves, namely ea15, ea18, and ea20
>>
>> Add other items to the list as necessary.  And if anyone would like to
>> elaborate on what is known or unknown about these, that could help
>> form a basis for designing and prioritizing tests.
>
> Not very important, but it comes to mind because of recent coversations.
> 7.  Investigate the "5MHz comb" seen in the 75 MHz band.  Two parts:
> decide whether it is strong enough to care about; and if so is there
> any easy (cheap) mitigation.
>
> Other stuff that comes immediately to mind involves testing/verifying
> yet unused correlator capabilities.  I don't think that is what you
> want for this list.
>
> Ken
>



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