[evlatests] The Return of integer zeros ...

[Rick Perley]

    yep -- and in reviewing my other test, also done last Friday, I see 
that in IF 'D' only there are many blank entries.  This experiment used 
the old 'RSRO' mode -- eight subbands.  Neither this test, nor my test 
from last night used referenced pointing. 



Bryan Butler wrote:
>
> i had a test from last friday that had very odd behavior in the BD 
> pair.  here are my notes from the data reduction yesterday:
>
>    very weird effect in the 2nd baseband.  for the LL correlations
>    (IF D), there are a bunch of missing baselines (missing in
>    the sense that they are blanked) for the 2nd half of the SB, which
>    was after a reference pointing scan.  for the RR correlations,
>    (IF B), this is true throughout the SB.
>
> this was Ku-band, with AC tuned from 13-14 GHz, and BD tuned from 
> 16.5-17.5 GHz.
>
> so i just had a look at the BDF2AIPS log file:
>
> Wrote 963600 visibilities, drop 50574 all zero.
>
> so more than 5% identical 0's.
>
> i can make a list of the baselines that have the 0's if it will help.
>
>     -bryan
>
>
> Rick Perley wrote, On 11/7/12 7:55 :
>>      We ran a 'PDif Compression' test last night.  In reviewing the 
>> data,
>> I find that large fractions of some of the scans contain 'integer zeros'
>> (and hence are removed by BDF2AIPS).  In column listings, some baselines
>> are fully present, but about half the baselines have only ~25% of the
>> data.
>>
>>      The data were taken in a simple mode:  Only two subband pairs, one
>> from the AC IFs, the other from the BD IFs.  The problem is not
>> uniformly seen across all bands --
>>
>>      Only for K, Ka, and Q bands, and only on IF 'D'.
>>
>>
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