[evlatests] Antenna 22 polarization at X-band ...

[Peggy Perley]

Bob,

   Thanks for the analysis.  Brent will try to get someone to look at 
this today and check the cable - not sure if we have the manpower today 
to drop the receiver, but we'll follow up on this.

Peggy

Bob Hayward wrote:
> Except this is an old X-Band receiver with a Septum Polarizer. This is 
> not a typical failure mode.
> 
> If it was a C-Band receiver, say, with a bad connection on one of the 
> linear polarization output from OMT to the 90 deg hybrid coupler, it 
> would make sense (i.e., degrades the Trx by a factor of 2 and makes it 
> linear polarized). So I'm puzzled...
> 
> We should probably drop the receiver to see if there is any debris on 
> the vacuum window (such as metal shards from the feed).
> 
> -Bob
> 
> 
> Ken Sowinski wrote:
>> On Thu, 23 Dec 2010, Rick Perley wrote:
>>
>>>    In calibrating the X-band 'Hercules A' demo project data, (taken
>>> last week) I find that antenna 22 is 100% polarized!  This invariably
>>> means that only one of the two linearly polarized outputs from the OMT
>>> is actually being used ...  A cable is disconnected?
>> This is surely the explanation for the poor amplitude
>> eresponse from ea22 at X band that we have noticed for
>> many weeks.
>>
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