[daip] VLBABPSS

[Eric Greisen]

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