[daip] a problem with apcal

[Eric Greisen]

Thomas Krichbaum wrote:
> Hi,
> 
> I need your help/advice. I already spent many hrs but could not find a solution.
> I work on a already fringe fitted data set (3mm data) and I want to apply the ampl. calibration.
> I loaded the antab files as usual with ANTAB and get a TY1 and GC1. SNPLT shows TSYS in
> TY1 and everything looks quite right.
> When I now apply APCAL (with or without opacity correction) the SN table is incomplete. For several 
> VLBA stations the resultant SN-table shows only a few  data points either at the beginning or end of the experiment
> with huge gaps inbetween. I tripple checked the cal file, and made also a fake cal file to be sure that
> nothing is wrong. Even with a simplified fake antab file (constant tsys, one TSYS number per scan) I get the same
> result. The SN table produced by antab is missing the corresponding data points for the gain. 
> Despite I have continues TY entries over up to 8 hrs, APCAL writes only very few entries
> in the SN table.  I also tried version OLD and NEW, the same. I copied out a portion of the data and
> run INDXR again, still the same. Even in the most simple mode of APCAL (no opacity correction) still the same.
> 
> Any idea why this is happening. It is the first time I see this effect. 
> 
> best regards, Thomas
> 
Please send messages to daip at nrao.edu since Amy knows a lot about VLBI 
and can answer things in my absence.

APCAL cares a great deal about subarray so if you have more than one 
there could be an issue of the subarray attached to the TY table 
entries.  APCAL should be smart enough to take a TY table subarray of 0 
to mean any but it does not do that at present.  That should be fixed.

Eric Greisen