[evlatests] status, Aug 24 2006

[Ken Sowinski]

Jerry visited antenna 18 after lunch and added the foot of
cable between the L305 and the BD L302.  We should see if
it is any more stable now.

Rick has had much to say about phase curiousities that may
be related to holography.

I spent some time looking at pointing primarily to get
Q band to be more robust at antenna 16 and 18.  There was
a significant focus error at 18 ( the result of a typo)
and large collimation errors at both antennas.  All this
has been repaired and 16 and 18 now look quite good at
Q band.

Except that the BD IFs don't work.  There is power and
switched power at the T5 but no correlated signal at all.
All IFs work for 13 and 14, so it is unlikely to be a
software problem.  All IFs work at K band so it is unlikely
to be a T303 problem.  Antenna 16 lacks an M301, so it is
unlikely to be an M301 problem.  All the L302s *claim*
to be in lock.  I did not try very hard to try to make
them prove it.  I suspected the transition module parameters
but trying all combinations of band select and inversion
was unsuccessful.  There is probably a clue in the fact
that earlier today 18 BD worked while 18 AC was broken.

There is still the curious problem that the SD for antenna
13 is much too small, only at K band, so that the amplitudes
are falsely raised when the T_sys correction is applied.
There is no evidence that the T_sys is really elevated.