[evlatests] More initial results from full WIDAR

Rick Perley rperley at nrao.edu
Thu Feb 4 19:09:28 EST 2010


    Upon further calibration ...

    Bandpasses look normal on all unflagged antennas. 

    A very few antenna-based flags were needed on some antennas to 
remove low amplitudes.  These were the same for all subbands of a given 
antenna and polarization. 

    Apparent closure levels are disturbingly high (10% !) -- and are 
certainly clustered on some antenna pairs:  3-5, 5-19, 3-19, 14-16, 
14-18, 14-28, 3-14, 5-14, 11-14.  The application of BLCAL totally 
removed these offsets, giving an absolutely perfect distribution of 
amplitudes and phases.

    3C84 has an extensive halo -- it is a very poor choice for closure 
check.  And, because we still have a number of 'old style' OMTs out 
there which are known to cause closure offsets due to 2nd order leakage, 
I urge the observers to observe one of our favorite point-sources 
('dots') at X-band. 

    One baseline (4 x 20) has a clear double-frequency (beat) wobble. 

  



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