[daip] VLBABPSS

[Walter Brisken]

I read the help from a distance, so must have missed the 'NOT'.  Anyway, 
changig the state of this to the non-default value (from VLBABPSS 
perspective) allowed solutions to pass that otherwise would not have. 
There is still a puzzle remaining here...

-W

On Fri, 3 Aug 2018, Eric Greisen wrote:

> On 08/03/2018 10:35 AM, Walter Brisken wrote:
>>
>>  Hi DAIP (probably Amy?)
>>
>>  Tom and I are looking at some of his data that he is processing using the
>>  VLBA scripts in AIPS.  After running VLBABPSS it is apparent that nearly
>>  all of the LCP channels are getting flagged by the BPASS task.  If we tget
>>  BPASS to see the parameters that are used we find BPASSPRM(5) is set to 1,
>>  indicating desire to "divide by channel 0".  I worry that this is both
>>  unnecessary and potentially problematic.  Indeed, setting this parameter
>>  to 0 and running BPASS in its naked form results in sensible bandpasses.
>>
>>  Is this a known issue?  Are there reasons that "divide by channel 0" is
>>  actually the right thing to do?  Seems like any normalization that this
>>  helps accomplish will be undone first by the normalization specified by
>>  BPASSPRM(10), and later by ACSCL.  Maybe I'm missing something subtle?
>>
>>       -Walter
>> 
>
> You did not read the help file.  BPASSP(5)=1 means do NOT divide by channel 0 
> and do the normalization after the fit based on the value of BPASSP(10). 
> Setting it 0 causes the normalization to be done record by record.
>
> Eric
>

-- 
-------------------------
Walter Brisken
Director
Long Baseline Observatory
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