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lbaops:lbanov2012:v471bcdlog

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lbaops:lbanov2012:v471bcdlog [2012/11/13 10:47]
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lbaops:lbanov2012:v471bcdlog [2012/11/16 12:34]
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 Coherence confirmed with tone of 841.4 MHz. Coherence confirmed with tone of 841.4 MHz.
  
-Channel 1 (RCP) shows intermittently fluctuating power levels and Tsys. Cause seems to dodgy programmable attenuators. (Not easily fixable.) Possible that the recorded data may not be affected too badly, but not sure at this stage. In previous 22 GHz experiments with a more sensitive setup, data *was* affected (though fringes were still confirmed), but things have been re-cabled since then and Brett thinks the current setup may guard against strong affects on the data. In any case channel 2 (LCP) appears to be OK...+Channel 1 (RCP) shows intermittently fluctuating power levels and Tsys. Cause seems to dodgy programmable attenuators. (Not easily fixable.) Possible that the recorded data may not be affected too badly, but not sure at this stage. In previous 22 GHz experiments with a more sensitive setup, data *was* affected (though fringes were still confirmed), but things have been re-cabled since then and Brett thinks the current setup may guard against strong affects on the data. In any case channel 2 (LCP) appears to be OK... Results from Bruce scans to calibrate tsys 1 and tsys2 (courtesy of Jamie MacCallum) below: 
 +----------------------------- 
 +Results after LBA run: SEFD @ 1650 is ~1200 Jy for both polarisations\\ 
 +SEFD @ 1370 is ~1500/1450 Jy for RCP/LCP\\ 
 +CALs are 36/42 Jy at 1650 (RCP/LCP)\\ 
 +CALs are 442/267 Jy at 1370 (RCP/LCP)\\ 
 +1370 scans were remarkably interference free.\\ 
 +1650 suffered intermittent RFI, sometimes enough to swamp Virgo. Peak amplitude of RFI pulses was ~2000 Jy\\ 
 +RFI sometimes showed time/spatial structure (appeared as regular variations during a scan but it's not clear whether it's pulsed in time or if it's something being scanned into sidelobes or the like.\\ 
 +All flux density calibrations performed using Virgo. 
 +----------------------------- 
  
 Drive PC problem in first few mins of experiment. On source from UT 06:17. Drive PC problem in first few mins of experiment. On source from UT 06:17.
lbaops/lbanov2012/v471bcdlog.txt · Last modified: 2015/12/18 16:38 (external edit)