[evlatests] evla problems, Jan 10 2005

[Ken Sowinski]

Much had degraded because of the swapped downconverters and 
DTS modules.

Antenna 13
IF C was fine; IF A worked after the DTS mib was used to
cycle power on the sampler and formatter.  There has been
some folklore that the D/A in the deformatter doesn't 
always work properly but will sometimes be fixed when
the DTS module is reset, so this may indicate a deformatter
problem rather than a DTS problem.  Pointing and delays were 
then set.

Antenna 14
Only IF C is working.  Some constellation of downconverter,
DTS module and deformatter problems keeps the other IFs from
working.  As far as I can tell each IF seems to be suffering
from a different problem.  Eventually I stowed the antenna
and left it for the Rob, Kerry and Jim.

Antenna 16
Had not been touched so all four IFs are still working.  However
it seems clear that its sensitivity is degraded and has been for
a while now.  This is true at all bands not just K and Q.  If
the SD voltages are to be taken seriously a high T_sys is 
indicated.


Once antenna 13 was made to work I gave up and devoted the
rest of the time to pointing to try to improve the model for
antenna 13 on the master pad.  This is worthwhile because the
last time antenna 13 worked we had ot yet sorted out all the
SW problems in pointing EVLA antennas.