[daip] bug in FITLD ?

[Floris van der Tak]

Dear AIPS team,

There may be a bug in the way FITLD writes GC tables for VLBA 
data sets with different bandwidths in different IFs.

My VLBA experiment BT079, observed last November 14, has three IFs
with 4 MHz and one IF with 2 MHz bandwidth. Each IF has 128 spectral
channels. The data were put on tape in seven files: three for the 
1-IF and four for the 3-IF data.

Reading these data into AIPS all at once, FITLD wrote two files. The
amplitude calibration with APCAL fails on the file with 3 IFs, with
the error message "missing gain". But APCAL works for the 1-IF file.

If FITLD just reads the 3-IF data (skipping the first three files) it
writes one file, which APCAL can handle.

The corrupted GC table has 40 rows where the others have 10. It looks
like the bad one just says the same thing four times.

Hope this helps,
   Floris

......................................................................
.Dr. Floris van der Tak                       vdtak at mpifr-bonn.mpg.de.
.Max-Planck-Institut für Radioastronomie       phone: +49 228 525 126.
.Auf dem Hügel 69, 53121 Bonn, Germany           fax: +49 228 525 229.
.http://www.mpifr-bonn.mpg.de/staff/fvandertak/          office: 2.31.
......................................................................