[IGSSTATION-5042] GODE and GODZ antenna failure/repair status

Stowers, David A (3350) david.a.stowers at jpl.nasa.gov
Tue Aug 7 09:42:52 PDT 2012


Author: Dave Stowers

Please be advised,

As noted in [IGSSTATION-5037]:
In an unfortunate coincidence, the GODE antenna experienced a failure of its LNA while
the in-situ IGS dome calibration experiment was in process (dome removed). During trouble
shooting, a Trimble choke ring antenna was mounted it place of the failed AOA unit. 

This downtime period is now over, the repairs to the LNA have been completed, and the  AOA 
D/M choke ring antenna (S/N: 129) for the GODE and GODZ stations  was  replaced on the 
monument fixture at 1319 UTC on August 7th (DOY 220). 

The antenna was returned to its original position and orientation, clamped properly within 
the fixture bracket with the fixed- height centering pin in place at the monument center point
(which was an issue with the Trimble unit ... there being some minor mechanical differences
between it and the older AOA version).

Once data operations and quality is verified, another announcement will be provided.

An updated sitelog is being generated, detailing the antenna change sequence/events.

As the electronics in the antenna have been changed (however slightly), I suggest the
uncalibrated dome remain off for at least another 8 weeks; long enough to notice any
apparent position changes from the pre-failure period and then to continue the in-situ
testing.

-dave

David Stowers,  Jet Propulsion Laboratory/Caltech
Product Delivery Manager, Global Observing System - GNSS
Tracking Systems and Applications Section - 3350
4800 Oak Grove Drive, M/S 238-600, Pasadena, CA, USA
Tel. +1 818-354-7055, fax +1 818-393-4965, E-mail dstowers at jpl.nasa.gov






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