[evlatests] VLA Test Meeting Agenda

[Deb Shepherd]

Hi All,

As per the EVLA test discussion today, a modified ACU scientific test plan
for EA21 is below.

Cheers,
Deb

13jun13 – Thursday

*Draft ACU scientific test plan for the new VLA ACU to be installed on EA21*

The new and old ACUs use the same commands through the executor so
scientific testing will focus on comparing the performance of the new ACU
relative to the old ACU.

Before the new ACU is installed on EA21 (it goes into the barn on 18 June)
a number of baseline tests will be done to make sure we have good measures
of the performance of the old ACU:

·      PN3dB tracking test - this will be scheduled by Vivek and Ken for
30min this weekend

·      30min pointing run with 50ms dumps at X and L bands.    X band is
the standard band to do this but the steps are larger at L band and may
excite other problems that would be useful to catch.      Vivek and Ken
will schedule this this weekend.

o   Note that when we compare the pointing model derived with the old and
new ACUs there should only be collimation differences.   If there are any
other differences then there is something wrong.

·      We should do beam cuts in both principle axes on a very bright
calibrator with fast dumps (100ms).    Rick will do this.   He will use
both X and L bands to look at the speed with which the cut is made, look at
how smooth the motion is and measure the oscillations at the end and how
fast they damp out.

After the new ACU is installed, the above 3 tests should be repeated and
results compared.   In addition, we should:

·      Observe 2 sources that are relatively far apart on the sky to check
the slew times.

·      Do a reference pointing test at high frequency and compare the
results.      We should be able to use the PL output to check the reference
pointing results or we can set up a quick high frequency run to do a final
verification that all is working properly.

Ken notes: the first real astronomical check is to verify that the azimuth
scale is consistent with all the other antennas.  That is something that
the engineering tests could easily overlook; it is the first thing to check
if there are no fringes when this is first tried.





On Wed, Jun 12, 2013 at 4:39 PM, Rick Perley <rperley at nrao.edu> wrote:

>     The monthly VLA 'science/engineering' Test meeting will be held at
> 10AM tomorrow (Thursday), 13 June, in Rm 317.  We have four items for
> discussion (so far):
>
>     1) Initial results from new 4-band dipole feeds  (Frazer).
>
>     2) Temperature dependencies of VLA antenna gains  (Rick)
>
>     3) Concerns obout R-L phase stability at high frequencies  (Rick)
>
>     4) Antenna tests for ea21, prior to the ACU conversion (all).
>
>
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>


-- 
Debra Shepherd <dshepher at nrao.edu>
National Radio Astronomy Observatory
1003 Lopezville Rd
Socorro, New Mexico 87801
http://www.aoc.nrao.edu/~dshepher
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