[daip] [!11758]: AIPS - CALIB puts different SNR into output SN table depending in APARM(6)

[Eric Greisen]

Eric Greisen updated #11758
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       Staff (Owner): Eric Greisen (was: -- Unassigned --)
              Status: Closed (was: Open)
           Reply due: - Cleared - (was: 13 March 2018 10:28 AM)

CALIB puts different SNR into output SN table depending in APARM(6)
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           Ticket ID: 11758
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/11758
                Name: Michael Bietenholz
       Email address: mbieten at yorku.ca
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Closed
            Priority: Default
      Template group: Default
             Created: 09 March 2018 10:28 AM
             Updated: 09 March 2018 04:29 PM

I am assuming that you had SNRmin = 4.  Antennas with only one or 2 samplesin an interval are assigned SNR = SNRmin + 1.  When APARM(6) = 3, the test on closure error essentially goes away so those samples with closure error areleft in and so there are > 2 samples, allowing a real SNR (perhaps wrong) to be computed.  If the complex gains do not change then there is little to worry about and this is just one of those arcane details buried in CALIB.The SNR can now be used in EDITA for flagging visibility data so perhaps thedocumentation should be enhanced.Eric Greisen


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