[evlatests] Phase stability of ea27 {External}

[Ken Sowinski]

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:
>>>>
>>>>> If we have a loose connection between the L300 and LO or DTS
>>>>> splitters, something like this could occur. Do we see this effect in
>>>>> both 8-bit and 3-bit?
>>>>
>>>> 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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