[evlatests] 'Missing' panels on ea21

[Dave Parker]

Sorry, found some old forms and it was Ant 20 that lost the panels.

Dave

On 5/20/2021 5:46 AM, Dave Parker via evlatests wrote:
> I antenna 21 the antenna that had a panel blow off in high winds a year 
> or two ago, and was holography done on it after it was reinstalled?
> 
> Dave
> 
> On 5/19/2021 3:01 PM, rperley via evlatests wrote:
>> I'm reviewing all the surface holography taken over the past three 
>> years.  The good news is that there is ample evidence that the panels 
>> don't change over this period of time, so that once we've made our 
>> 'best' adjustments, no more adjustments will be needed for a long time.
>>
>> The 'bad' news is that something is quite amiss with ea21.  We're 
>> getting no signals from two panels - this is seen in both the Jan 2019 
>> and May 2020 data.
>>
>> Of course, these panels cannot be 'gone' (one hopes that somebody 
>> would have noticed this, were that the case ...).  What has happened 
>> is that the two panels are tilted so much that we don't get a coherent 
>> signal over the resolution of the measurements.
>>
>> The two panels are in the outermost right, and, as seen from the 
>> front, looking into the dish, are the top two panels on the right side 
>> of the quad leg.
>>
>> It would be useful for somebody to look at these -- the effect will be 
>> very slight, so don't expect an obvious tilt.  It takes only a couple 
>> of millimeters of slope, over the extent of the panel, to make it 
>> 'disappear'.
>>
>> Rick
>>
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