[evlatests] Current status

[Jim Jackson]

We mainly worked on Antennas 18 and 26 today.  I did not hear of problems 
with 24 until we got back to the AOC so we didn't do anything with 
it.  Barry - Which L302 did not lock at C-band in 24?  We have one with 
some updated firmware Pete and Matt just finished and we want to try it.  I 
was wondering where to install it and this sounds like as good a place as any.

Antenna 18:  The same as a couple of weeks ago, we found very low power 
from the C-band receiver RCP output. The front end group believes there is 
either a broken semi-rigid cable between the dewar and RF box or a post amp 
is oscillating.  It is working for now - Brent is having a new cable made 
up and will replace it. If the problem recurs, we'll check for the 
oscillation with a spectrum analyzer - the receiver may have to be pulled 
from the antenna for repair if that is what is happening..

Antenna 26:  The sync problem is fixed - there is confusion on a command in 
the new version of the L353 - "Sync Enable" needed to be set to "0" to 
enable sync, not "1". This will be corrected in firmware in the near 
future. The L305 is now synchronized. Other than that, the antenna is still 
sick.  There is insufficient power from the X-band receiver to get 
sufficient levels to the digitizers on RCP.  LCP is 3dB higher and works 
but is still very marginal. Post amps need to be added to this receiver. 
L-Band did not work because the T302 seems to have a problem with the +17V 
power supply - likely a blown fuse on the DAQ1. It was brought back for 
repair.  K-band is a complete mystery.  The T303 UX Converter, switches and 
wiring seem to be fine.  The next step was to check out the receiver and 
test the LO cable but we ran out of time. I also noticed there is no dummy 
F317 in this antenna to provide 9.6Hz to the new card cage on the K-band 
receiver - so even if it was working, there would be no switched power.

Jim


t 04:25 PM 10/18/2006, Ken Sowinski wrote:
>On Wed, 18 Oct 2006, Barry Clark wrote:
>
> > X band.  18 is a little weak, but maybe because the delays are misset.
>
>Delays almost certainly need help if the antenna is on a
>previiiously unused pad.  If it is off by more thann about 20 ns
>looking at the phase slope in line mode  is the easiest way.
>I put an initial guess in SYSPATHF for alll the pads we expect
>to use and that can be adjusted.
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