[evlatests] phase noise on outer antennas {External}

[Paul Demorest]

I dug around a bit in the archive.  There is not a lot of high-freq fast-dump data for a direct test, most of this work was done at lower freqs.  However I did find one 10ms X-band A-config data set from 2012!  The 2012 data do show some of this noise on two of the outer pads (E72, N72), but the worst RMS is only ~half of what it is currently and W72 looked fine.  That might be (weak) evidence for degradation.. or that might be over-interpreting one 12-year old data point.. 

Updated data set summary is attached if anyone wants to explore further.

________________________________________
From: evlatests <evlatests-bounces at listmgr.nrao.edu> on behalf of Rick Perley via evlatests <evlatests at listmgr.nrao.edu>
Sent: Tuesday, October 29, 2024 11:10 AM
To: Leon Abeyta; Ken Sowinski; evatests; Jim Jackson
Subject: Re: [evlatests] phase noise on outer antennas {External}

I'd like to think that I would have noticed degraded sensitivity in my various A-configuration observations done in the past which involve those end stations.  No such effect comes to mind, but will admit that this is not something I would have noticed unless the sensitivity loss was more than, say, 50%.

Rick
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From: evlatests <evlatests-bounces at listmgr.nrao.edu> on behalf of Jim Jackson via evlatests <evlatests at listmgr.nrao.edu>
Sent: Tuesday, October 29, 2024 9:58 AM
To: Leon Abeyta <labeyta at nrao.edu>; Ken Sowinski <ksowinsk at nrao.edu>; evlatests <evlatests at nrao.edu>
Subject: Re: [evlatests] phase noise on outer antennas {External}

Is this phase noise something that been looked at before and wasn't occurring or is this something new that we've never actually looked at this deep before?    I'm trying to figure out if this could be something that has degraded or if it's something that has really always been there and was just never noticed.

Jim

-----Original Message-----
From: evlatests <evlatests-bounces at listmgr.nrao.edu> On Behalf Of Leon Abeyta via evlatests
Sent: Tuesday, October 29, 2024 9:32 AM
To: Ken Sowinski <ksowinsk at aoc.nrao.edu>
Cc: evlatests at listmgr.nrao.edu
Subject: Re: [evlatests] phase noise on outer antennas {External}

The original alerting range is -15 to -21. It probably goes back to when the L304 was first designed.

Leon

On 10/29/2024 9:26 AM, Ken Sowinski wrote:
> On Tue, 29 Oct 2024, Leon Abeyta via evlatests wrote:
>
>> It's "OPT_PWR".  Typically -18 dBm.
>
> Thanks.  so it is.
>
> ea18    <monitor name='OPT_PWR' type='analog' value='-16.078757'
> ea21    <monitor name='OPT_PWR' type='analog' value='-18.479333'
> ea24    <monitor name='OPT_PWR' type='analog' value='-19.486055'
> ea26    <monitor name='OPT_PWR' type='analog' value='-13.920063'
>
> ea02    monitor name='OPT_PWR' type='analog' value='-17.989920'
>
> Only ea18 is dowN by a dB and a half.  We will have to look arder.

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