[daip] [!10559]: AIPS - general instrumental calibration with question

[Sarah Spolaor]

Sarah Spolaor updated #10559
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general instrumental calibration with question
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           Ticket ID: 10559
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/10559
           Full Name: Sarah Spolaor
               Email: sarahbspolaor at gmail.com
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 21 June 2017 03:00 AM
             Updated: 21 June 2017 03:00 AM
                 Due: 23 June 2017 03:00 AM (2d 0h 0m)
      Resolution Due: 29 June 2017 03:00 AM (8d 0h 0m)



I'm having some trouble getting reliable amplitude scales on the phase calibrators in BS237, one of the large filler programs. So, I'm now trying to go through the calibration carefully step by step and re-learn the calibration process by looking at various tutorials and going through the cookbook procedure (the latest one online). I'd like to identify exactly where in my process the data is going awry, but I'm sadly kind of a newbie to VLBA calibration (others have done the cal in the past).

I'm currently correcting instrumental delays with some fairly standard S/X receiver continuum data from Nov 2014 (BS237B9). I'm using the pulse-cal, which appears to be available for all antennae... and I get the attached images after running VLBAPCOR. X-band seems to have turned out fine. However (even ignoring bad chans 5 and 8) S-band has a few ratty antennae---BR, LA, HN, NL---particularly as the cookbook notes the following:

"If you see significant phase slopes, or phase jumps between IFs on any baseline, then the instrumental phase corrections have not worked and you need to figure out why and start again."

I guess my most fundamental question is, "how significant is significant"? Are my S-band results sufficiently OK that I can simply move on (I suspect not)?

If not, I can't work out from the cookbook how to proceed identifying and correcting the remaining frequency-dependent phase drifts. I have GC, TY, WX tables for the antennae, and those antennae don't have any obviously bad data or Tsys values over the time ranges I'm considering here, nor were they fagged in the log. Is there something obvious I'm missing?

Thanks,
Sarah


PS I will tack on a less urgent "could a simple reference graphic of bad and good plot examples be added to the cookbook at various stages to help other users who might have similar questions at various stages of the analysis"? 

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