[daip] PCAL

[Jim Ulvestad]

Sorry, got the task name wrong!  Was thinking of PCCOR.

jim

On Mon, 7 May 2001, Leonia Kogan wrote:

> Jim,
> 
> I guesss you think that PCAL uses pulse cal tones. That is not true.
> PCAL computes polarization corrections of the antenna feed using the
> calibrator with known polarization property. It has nothing to do with 
> pulse cal tones.
> 
> PCAL averages frequencies of the calibrator signal at each IF. 
> That naturally requires flat phase within each IF.
> 
> Leonia
> 
> 
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> >From owner-daip at kochab.cv.nrao.edu Mon May  7 07:01 MDT 2001
> Date: Mon, 7 May 2001 06:51:22 -0600 (MDT)
> From: Jim Ulvestad <julvesta at cv3.cv.nrao.edu>
> X-Sender: julvesta at hayduke
> To: Leonia Kogan <lkogan at cv3.cv.nrao.edu>
> cc: daip at cv3.cv.nrao.edu
> Subject: [daip] PCAL
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> Sender: owner-daip at kochab.cv.nrao.edu
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> 
> Leonia's comment in CHANGES.DOC says that data should be
> phase-calibrated before PCAL.  What does this mean?
> PCAL has previously been used to do the delay
> calibration for each IF in VLBA observations, and
> there is no phase calibration before that (only
> the parallactic angle correction).  If I interpret
> Leonia's message correctly, he seems to me to be
> saying that you have to fringe-fit before
> running PCAL, which takes away the whole point of
> using the pulse-cals to do the initial delay
> calibration in continuum observations.
> If you average the pulse-cals in a given IF, then
> how do you use them to get delays?
> 
> Perhaps I'm being dense or jet-lagged or just plain
> misunderstanding the message, but this strikes
> me as being a problem.
> 
> jim 
> 
> 
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>