[evlatests] X-band yesterday

Bryan Butler bbutler at nrao.edu
Thu Aug 2 15:25:19 EDT 2007


the Tsys data will be "logged" at every integration interval - they are in the 
archive records at whatever interval the visibilities are recorded at.  this 
might be an odd interaction between FILLM and the archive, for datasets with 
mixed integration lengths.

	-bryan


On 8/2/07 13:18, Rick Perley wrote:
>     All 27 antennas worked very well. 
> 
>     But a remarkable 'feature' in the TY table was discovered:
> 
>     The X-band observations were set up in a special way, to avoid a 
> known 'feature':  It seems that the scan which *precedes* a reference 
> pointing scan will always fail to give any data.  Ken says this is a 
> known problem, which will be repaired soon. 
> 
>     In my 'stress test', I run a 'reference pointing' at X-band.  To 
> avoid wiping out the preceding C-band observation, a 'dummy' X-band 
> observation was inserted between the C-band and the X-band reference 
> pointing.  This 'dummy' scan requested 10 second integration.  The 
> reference pointing also used 10 second integrations, while the real 
> X-band on-source observation (which followed the referenced pointing) 
> used 0.416 second averaging.
> 
>     The visibility data were exactly as expected.  However, when I went 
> to review the Tsys data (in the TY table), I found to my amazement that 
> the data were logged only once every 10 seconds (which is the interval 
> set by the preceding two scans, at this band). 
> 
>     Looking ahead (U-band), all rates, in both visibility and monitors, 
> were at the requested 0.416 second rate. 
> 
>     Why were the Tsys data only logged once per 10 seconds? 
> 
> 
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