[daip] [!5168]: aips - Frequency dependence of the amplitude after VLBACALA

[Amy Mioduszewski]

Amy Mioduszewski updated #5168
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                 Due: - Cleared - (was: 29 July 2014 12:24 PM)

Frequency dependence of the amplitude after VLBACALA
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           Ticket ID: 5168
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/5168
           Full Name: Svetlana G. Jorstad
               Email: jorstad at bu.edu
             Creator: User
          Department: AIPS Data Processing
       Staff (Owner): Amy Mioduszewski
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 14 July 2014 09:52 AM
             Updated: 25 July 2014 01:27 PM
      Resolution Due: 24 July 2014 09:58 AM 



Hi Svetlana,

O.K., since it only happens after APCAL and with and without opacity fitting then it sounds like it is in the Tsys.  I looked at the Tsys file for BR for your experiment and all the LL Tsys fluctuate between 98-102 and the RR go from 140 down to 45.    There have also been reports of amplitude oddities with a variety of antennas/polarizations/IFs, so this looks like issues with the new(ish) backends, i.e., this is a problem with the PFB.  I will talk to Craig about it (when I find him), but it doesn't seem like an AIPS problem, so I will transfer this to the VLBA side but it might be put on hold because this is part of a larger problem.  Thanks for reporting it.

As for how to get around this is AIPS, you could copy the LL Tsys to the RR.  I think TABED will do this.

Amy

Amy Mioduszewski
NRAO

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