[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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