[daip] BL149BE: PCOR problems

Yuri Y. Kovalev ykovalev at mpifr-bonn.mpg.de
Wed Dec 24 16:38:53 EST 2008


Thank you! Leonia, I fear that you are correct.
Here is the PC table header for SC (exp BL149BE):

FREQUENCY SC /
! Tone  Chan  SB   Pol   ToneSkyFreq #bits    LoFreq      BW
  'T01'   1   'L'  'RCP'    15333.00   1    15333.49    8000.0
  'T02'   2   'L'  'LCP'    15333.00   1    15333.49    8000.0
  'T03'   3   'U'  'RCP'    15334.00   1    15333.49    8000.0
  'T04'   4   'U'  'LCP'    15334.00   1    15333.49    8000.0
  'T05'   5   'L'  'RCP'    15349.00   1    15349.49    8000.0
  'T06'   6   'L'  'LCP'    15349.00   1    15349.49    8000.0
  'T07'   7   'U'  'RCP'    15350.00   1    15349.49    8000.0
  'T08'   8   'U'  'LCP'    15350.00   1    15349.49    8000.0
  'T09'   9   'L'  'RCP'    15365.00   1    15365.49    8000.0
  'T10'  10   'L'  'LCP'    15365.00   1    15365.49    8000.0
  'T11'  11   'U'  'RCP'    15366.00   1    15365.49    8000.0
  'T12'  12   'U'  'LCP'    15366.00   1    15365.49    8000.0
  'T13'  13   'L'  'RCP'    15381.00   1    15381.49    8000.0
  'T14'  14   'L'  'LCP'    15381.00   1    15381.49    8000.0
  'T15'  15   'U'  'RCP'    15382.00   1    15381.49    8000.0
  'T16'  16   'U'  'LCP'    15382.00   1    15381.49    8000.0
/

I see from our previous 256 Mbps experiments that indeed two tones per 
IF are used. I should say, I am not sure why. To get frequency 
dependence across the IF? However, I guess, one tone PC data could also 
be useful. If I understand correctly, as of now, there is no way in 
AIPS these data can be applied.

I do not think that using two times wider IFs would be an option for us.
16 MHz filters are not particularly good at VLBA.
I guess, we will wait until the digital backend when all these problems 
will hopefully be solved.

I Vas s Novym godom!
Yura

On Wed, 24 Dec 2008, Leonia Kogan wrote:

> Yura,
> 
> I may know the explanation of your problem, if you find that the number of
> tones at the PC table is one
> (look at the header of the PC table).
> Let me know please if it is true.
> The number of counter (pulse cal detectors) used for creation of the pulse
> cals is limited
> by 16. If you have 8 IFs and both polarizations, then the number of required
> counter is
> 8*2pol*2tones=32 > 16. SCHED, looking at this inequality, changes the number
> of tones to 1.
> I asked Craig Walker recently to change SCHED reporting user about the problem
> recommending user to
> decrease number of IFs for example. Your data were prepared before possible
> Craig's change of SCHED (?).
> 
> S Novim Godom!
> 
> LK
> Yuri Y. Kovalev wrote:
> > Dear colleagues,
> >
> > I continue to have fun reducing 512 Mbps VLBA experiment BL149BE.
> > This time I write you about phase calibration procedure vlbapcor.
> >
> > Here are parameters I use:
> > AIPS 1: VLBAPCOR: Procedure to correct instrumental phases
> > AIPS 1: Adverbs     Values                 Comments
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: INNAME     'BL149BE'               Input UV file name (name)
> > AIPS 1: INCLASS    'UVDATA'                Input UV file name (class)
> > AIPS 1: INSEQ         1                    Input UV file name (seq. #)
> > AIPS 1: INDISK        1                    Input UV file disk unit #
> > AIPS 1: TIMERANG      0          12        Time range of a calibrator
> > AIPS 1:              55          43         1-4 = start day,hr,min,sec
> > AIPS 1:               0          13         5-8 = end   day,hr,min,sec
> > AIPS 1:               0          23        MUST BE SPECIFIED
> > AIPS 1: REFANT        5                    Ref. antenna, 0=>the first
> > AIPS 1: SUBARRAY      0                    Subarray;  0 => all.
> > AIPS 1: CALSOUR    *all ' '                Calibrator source name;
> > AIPS 1:                                    blank => any
> > AIPS 1: GAINUSE       0                    CL table to use; 0=>highest
> > AIPS 1:                                    ADVERBS FOR ANTENNAS NOT
> > AIPS 1:                                    CONTAINED IN PC TABLE:
> > AIPS 1: INVER         0                    Input  PC table, 0=>last one
> > AIPS 1: OPCODE     ' '                     'CALP' if you are missing PC
> > AIPS 1:                                    information for any antenna;
> > AIPS 1:                                    otherwise ' '
> > AIPS 1: ANTENNAS   *all 0                  antennas for which manual
> >
> > It does not work reporting:
> > *****
> > PCCOR1: All rows of the PC table are bad for the selected parameters
> > PCCOR1: Purports to die of UNNATURAL causes
> > *****
> >
> > I tried MPIfR installed AIPS 31DEC07, 31DEC08, 31DEC09 with the same result.
> > I tried PC table which I got from the correlator AIPS friendly files (after
> > gluing) and I also tried "external" PC table from bl149becal.vlba using VLOG
> > & PCLOD. Result did not change.
> >
> > I wonder if you could take a look at it? Thank you.
> >
> > I remember that Matt had some problem applying PC table to the previous
> > MOJAVE VLBA 512 Mbps data (BL149BD), but I am not sure if it was the same
> > problem or something else. Matt?
> >
> > Cheers,
> > Yuri.
> >
> > _______________________________________________
> > Daip mailing list
> > Daip at listmgr.cv.nrao.edu
> > http://listmgr.cv.nrao.edu/mailman/listinfo/daip
> >   
> 




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