[evlatests] Direct Comparison of 3 and 8 bit gains

[Rick Perley]

    Michael R. asked for a direct one-to-one comparison of the 
visibilities from the 3-bit and 8-bit tests of last month.  I've now 
done this. 

    The data were taken in parallel, so that the two 3-bit and one 8-bit 
paths are at the same frequency and taken at the same time.  I did the 
comparison by generating the CALIB solutions (antenna-based gains) for 
the three paths, utilizing the subband covering 15.000 -- 15.128 GHz.  
The solutions were made from data without applying any prior 
calibration, utilizing only the central 10 MHz of data, on 3C84, which 
was taken to have 30.0 Jy flux density. 

    The results are shown in the attached .pdf files:  green is A1C1, 
red is A2C2, and purple is B0D0, all on the same scale. 
    The gains are the same to within 1% or so, with the major difference 
being simply one of normalization.  (AIPS clearly has a different idea 
of normalization than my eye -- I'll talk with Eric to see why this is 
so).  Beyond the normalization issue, there are some 'steps' in the 
gains for some antennas/IFs/paths which clearly are due to temporary 
antenna-based gain changes of <~ 1%. 
    All the slow changes (due to temperature, antenna gain, etc.) are 
identical. 

   
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ANT_18+23.pdf
Type: application/pdf
Size: 23535 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20111215/7ce2f266/attachment.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ANT_10+14.pdf
Type: application/pdf
Size: 21660 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20111215/7ce2f266/attachment-0001.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ANT_6+7.pdf
Type: application/pdf
Size: 24795 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20111215/7ce2f266/attachment-0002.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ANT_26.pdf
Type: application/pdf
Size: 19289 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20111215/7ce2f266/attachment-0003.pdf>