[evlatests] Quasi-calibrated visibilities and weights!

[Rick Perley]

    Exactly so.  The 'discrepancy' was seen in all four correlations 
(both pols and both IFs), so it's more likely one of the two things 
Barry indicates.

    A more systematic search is warranted.  This can be done easily 
using (preferably) 3C286. 

   

Barry Clark wrote:
> It seems unlikely that a presumed efficienty would be too low.  If
> both right and left are indicating similar gain anovalies, it would
> seem to me to indicate that the cal source itself or the cal coupler
> has become deranged.  Is it worth the effort to send somebody upstairs
> with hot and cold loads to check?
>
> Rick Perley wrote:
>   
>>     It appears some troubles (most hidden from public view! :) 
>> concerning proper application of the 'switched power' quantities are now 
>> behind us.   The raw visibilities and weights offered by BDF2AIPS, after 
>> passing through Eric's latest version of TYAPL, are now in real Jy 
>> (visibilities) and (1/Jy)^2 (weights), as they should be. 
>>
>>     One nice advantage of this is that we can quickly find antennas 
>> whose TCals or presumed efficiencies are 'out of line'. On a short test 
>> database taken at noon today, of 3C454.3 at Ka-band, the post-TYAPL 
>> visibilities are mostly near the correct value  of 38 Jy, but three 
>> antennas are far away:  Antennas 17 and 26 give visibilities which are 
>> much too low, and antenna 14 gives visibilities which are much too 
>> high.  For the former, either the listed TCals are too low, or the 
>> presumed antenna efficiency is too high.  For the latter, the inverse 
>> applies. 
>>
>>    
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