[evlatests] EVLA tests, Dec 15 2005

[Ken Sowinski]

                        EVLA Tests, Dec 15, 2005

We are still recovering from all the HW activity of the last few days.  

1.  ea16-l302-2 was in standby and had to be rebooted before it worked
again.  The Mloop claimed to be out of lock.
2.  Antenna 14 worked only at C band.  No backend power perceptible at
any of the other bands.  It turned out to be a blown fuse.
3.  Antenna 14 IF C was not very happy: low SD voltage and low
correlated signal.  The consensus is that there is a downconverter
problem.  Running the attenuator up and down in 6 dB steps does not
give the expected behavior.  No matter how much attenuation in the
path, the T5 ALC is always pegged in the large signal direction.

Because of the time spent tracking down these problems and discussing 
causes,not much else was done except to set delays again for antenna 
14, and 16 at C band.

For the last half hour Walter prepared a file which steps through bands
in various combinations to see what systematics we can discern in the
phase jumps previously reported.  When this file begin 16 BD was dead
and this was traced to the L302 in standby once again.  I rebooted it
once again.

I understand that the 14C downconverter will be looked at Monday morning.

Barry and Hichem spent the afternoon at the VLA working on controlling
VLA antennas.