[evlatests] antenna 23 (fwd)
Ken Sowinski
ksowinsk at nrao.edu
Tue Nov 28 19:14:04 EST 2006
I sent this out yesterday and never saw it appear.
Here it is again.
---------- Forwarded message ----------
Date: Mon, 27 Nov 2006 17:25:32 -0700 (MST)
From: Ken Sowinski <ksowinsk at eki>
To: evlatests at eki
Subject: antenna 23
Rob called a little while ago and said that antenna 23 ought
to work with IFs A, B and D; C would be unavailable because
he was going to return the D303 to Socorro. He was two-thirds
right.
Total power in IF B was a bit weak; I updated the attenuator
setting in the database from 9 to 3 dB. IFs A and B both
looked reasonable then and delays were set. IFs C, as expected,
and D did not work. However I found that the output attenuator
in the T304-D was not connected to the IF D sampler. Further
examination showed that the T304-C was connected to the IF D
sampler. I wonder if some of the confusion with C and D is
because of this miswiring between downconverter and samplers?
I started a long track on 3C345 beginning at 2356 IAT to try to
assess the stability of antenna 23. All the EVLA antennas were
included and claim to be working. There was a burble at IAT
midnight which is surely due to the Modcmops. I cursorily
watched the data go by sampling the baselin of antenna 6 with 23
and so only one interesting event at 00:06:20 IAT which changed
the phases for both IFs A and B. Someone should examine the
data with more care to see if it was all EVLA antennas or just
antenna 23. I also saw variations in amplitude of about five
percent on a time of minutes. Again a more careful examination
is needed.
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