[evlatests] [Nmipg] NM-IPG meeting Tuesday 19 November 10am MT {External}

[Rick Perley]

In the IPG meeting this morning, I made brief mention of some irregular, and short-duration P-band RFI noted in some recent data.

I reviewed more carefully the most recent example (taken yesterday afternoon).  The characteristics of this are most unusual:


  1.
It is of short duration — typically ten seconds.
  2.
All spectral windows are equally affected.
  3.
There is a spike of RFI at the same time with the same duration, at frequency 335.25 MHz, and a weaker one, at the same time, at 365.25 MHz.  The first of these has an amplitude about 13 dB above the noise-- not particularly strong.
  4.
The visibility amplitudes are dropped by about a factor of two during the event, on the affected baselines.
  5.
What is most peculiar is the antenna/polarization distribution of the observed event:
     *
In the 'V' signals, only ea05 shows this, on all baselines.
     *
In the 'H' signals, only ea09 and ea10 show this, on all baselines.
     *
Note that ea09 is at W56, ea10 at N48, and ea05 is at W40:  All widely separated, and far from the array center.

The observation that all baselines to certain antennas, in the A configuration, are affected would argue for a 'global' (i.e. distant) origin.  However, the fact that the compression is seen only on specific (widely-separated) antennas and polarizations argues most strongly for a source internal to the antennas.

This is a highly irregular event — typically seen only once or twice an hour.

Rick



________________________________
From: Nmipg <nmipg-bounces at listmgr.nrao.edu> on behalf of Ylva Pihlstrom via Nmipg <nmipg at listmgr.nrao.edu>
Sent: Thursday, November 14, 2024 9:50 AM
To: Ylva Pihlstrom via Nmipg <nmipg at listmgr.nrao.edu>
Subject: [Nmipg] NM-IPG meeting Tuesday 19 November 10am MT {External}

Hi All,

Our next NM-IPG meeting will take place Tuesday 19 November at 10am in SO-317.   We will plan on hearing updates from our various groups - please bring your RFI news.  As always, send me any additional agenda items you would like to add.

Ylva


—————————
Agenda (https://ngvla.atlassian.net/l/cp/9vzPmy1s):

1. Spectrum management (CDP/SW)
2. Science User Support: C-band RFI seen in B-config? (RP)
3. Electronics division (TM/RN/DS)
4. RFI GUI:  Brainstorm re functionalities (AL, all)
5. AOB

SO-317:
https://go.nrao.edu/so317zoom
 - Audio-only: +1 646 876 9923
 - Meeting ID: 505 244 9004
 - Passcode: 479680
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20241119/89c6618d/attachment.html>