[daip] DiFX, AIPS, APCAL and WX table

[Yuri Y. Kovalev]

Dear colleagues,

I used to have problems with the WX table doing opacity 
correction in APCAL many times in 2009. It was always solved by 
producing an external WX table by VLOG and then using external 
WX table in APCAL instead of the one coming with the correlator 
output.
I was hoping that the problem is gone since DiFX started its 
operations.
However, the problem is back again with DiFX and I wonder if you 
could take a look at it and fix it?

I have used:
BL149CG FITS IDI file from the NRAO archive,
AIPS 31DEC09 being continuously updated.

Commands:

** Calibrate amplitudes in APCAL
infil ''; SOUR = ' ';timer 0;
STOKES = ''; TYVER = MAXTAB('TY'); GCVER = MAXTAB('GC')
SNVER = MAXTAB('SN') + 1; OPCODE='GRID'; APARM=0; SOLINT=0
TAU0 = 0; DOFIT = 1; PRTLEV = 0; INVERS = 1
DOTV = FALSE; LTYPE = 3; APARM(5) = 5; TREC = 0;
INVERS = 1; CALIN ''
RUNWAIT ('APCAL')

Error messages log:

JET   > APCAL2: Task APCAL  (release of 31DEC09) begins
JET   > APCAL2: TABIO: BAD LRNO =      1523 LIMIT      1521
JET   > APCAL2: TABWX: ERROR   2 FROM TABIO OPCODE = READ
JET   > APCAL2: REAWX: ERROR  2 SOMETHING WRONG WITH WX TABLE
JET   > APCAL2: TXTWX: ERR  2 OPENING WX TABLE   1
JET   > APCAL2: Purports to die of UNNATURAL causes
JET   > APCAL2: jet          31DEC09 TST: Cpu=       0.0  Real=       0

I would expect this problem to be reproducible always.

Cheers,
Yuri