[daip] Re: IT's definitley STRANGE UVCOP

[Eric Greisen]

Hans-Rainer Kloeckner writes:

 > Sorry I'm somehow confused! I run into the
 > following problem. Using UVCOP to delete some visibilities works ONLY
 > if the BCHAN and ECHAN in the flag table is set to 1 0 otherwise UVCOP 
 > does not delete anything. I did the following experiment on several 
 > datasets:
 > 
 > I produce 2 flag tables with UVFLG one with
 > BCHAN 0, ECHAN 0 and one with BCHAN 40, ECHAN 41.
 > 
 > UVCOP only dropped some vis. records in the first case and
 > does nothing in the secound.
 > 
 > Is there some hidden knowledge why? If not and I hope it's not my AIPS 
 > version, do you see an easy way to fix that problem ?
 > 
In the 2nd case it will not drop a record, just flag channels 40 and
41 inside that record.  I bet if you run PRTUV on CHANNEL=40 you will
see that the UVCOP output has negative or 0 weight where the channel
is to be flagged.  Note that a UV data record contains all of the
channels and will be dropped only if all of the channels (and all of
the IFs and all of the polarizations) are flagged.

Eric Greisen