[evlatests] Update on Ka-Band Installation

[Robert Hayward]

Several steps backwards today on the installation of the latest A-Band
receivers...

On Antenna 25:

A-Band S/N 6 was installed last Wednesday but problems with the Card Cage
resulted in us returning the Card Cage to the lab for debugging. We
returned today with a unit we trusted but there appears there may be a
problem with the LNA on the LCP side which meant we had to pull the
receiver for further evaluation in the lab.

We did fix the K-Band receiver which, unknown to us, had been giving
anomalous read-backs and which was unresponsive to any command from the
F317. We discovered a bent pin on the Control/Sensor card connector so the
Card Cage from the A-Band receiver we had just removed was commandeered to
replace the defective unit.

Unfortunately, we did accidentally bump into the damned smoke detector
which has the annoying habit of killing the 48 VDC power to the
electronics racks. If the antenna is misbehaving, some of the systems may
need to be properly initialized.


On Antenna 1:

Last week's planned installation was aborted due to the A-Band S/N 5
receiver failing its leak test. After rework at the AOC, it passed today
and was hauled up to the Vertex Cabin only to find that the orientation of
the feed tower was misaligned so that we were unable to fit the receiver
to the "spider" properly. The receiver was carted back down and now sits
abandoned in the Pedestal Room until the Antenna Mechanics can help us
sort this problem out.


By the way, Q-Band S/N 19 passed its leak test today but we ran out of
time and were unable to install it on Antenna 28. Until this antenna's
pointing problems are sorted out, we'll worry about the more pressing
A-Band issues noted above first.

-Bob