[evlatests] Phase stability of ea27 {External}

[Paul Demorest]

As far as I know, no.

Jul 3, 2023 3:54:41 PM Ken Sowinski <ksowinsk at nrao.edu>:

> We learned that rsetting the L305 fixed it.
> 
> But did we ever learn the cause of the 10Hz phase signature?
> 
> Ken
> 
> 
> On Mon, 3 Jul 2023, Paul Demorest via evlatests wrote:
> 
>> Hi all,
>> 
>> Not sure if this is relevant but for the record:
>> 
>> Four antennas including ea27 have recently been showing large (20 to 30deg
>> peak-to-peak) phase modulation at 10 Hz: ea13, ea17, ea23, ea27.  We have seen
>> this kind of thing occasionally over the past few years and have found it can
>> be fixed by power-cycling the L305.  This was done June 7 and at the time
>> seemed to clear up the issue on ea13 and ea27.  However new data taken today
>> shows the 10 Hz has come back on these two.
>> 
>> I don't know if this issue is directly related to the phase jumps, however in
>> May, Drew reported phase jumps on three of these antennas in pipeline output
>> (ea13, ea23, ea27).  This is what led to looking at the high time resolution
>> data, and finding large 10 Hz on all of them seemed a bit suspicious.  Maybe
>> there is a common underlying cause for these two symptoms?
>> 
>> This was written up in WO-17369, 17370, 17371, 17372.
>> 
>> Cheers,
>> Paul
>> 
>>> Hello,
>>> 
>>> Eddy Sanchez verified cabling at the L300 and L305, cables at the
>>> splitters and in the Utility rack. He did not see anything loose.
>>> 
>>> Dave
>>> 
>>> On 6/30/2023 11:48 AM, Rick Perley via evlatests wrote:
>>>> Some support for a ratty connector:  In looking at my gain solutions, I
>>>> see that ea27 often has both ratty (variable) amplitudes and phases
>>>> within a scan.  No other antenna does this ...
>>>> 
>>>> On 6/30/23 11:44, Ken Sowinski wrote:
>>>>> On Fri, 30 Jun 2023, Rob Long via evlatests wrote:
>>>>> 
>>>>>> …
>>>>> 
>>>>> I think Rob has the right idea.  Given the pervasiveness it must be
>>>>> at the head of the LO chain (L300 to L305) or the LO transmitter; or
>>>>> The L302(s) not being phase stable with LO offsets.
>>>>> 
>>>>> Tha latter can be ruled out by running a test with the Widar offset set
>>>>> to zero.
>>>>> 
>>>>> Ken
>>>> 
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>> 
>> 
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