NOAA-16 - AMSU-A1 Oscillator Attempt to Correct, 25 November 2002 - Issued: 25 November 2002; 1730 UTC

Local Oscillator toggle to correct problems

Date/Time(UTC) Message Issued:
25 November 2002; 1730 UTC

Satellite(s) Involved:

Instrument(s) Involved:

Product(s) Involved/Affected:
All data users

Date/Time(UTC) of Initial Implementation:
25 November 2002 1730 UTC

Details/Specifics of Change:
After reviewing the NOAA-16 AMSU-A1 oscillator problem, the NOAA/NASA team
decided to attempt a correction by toggling between the redundant (PLLO#2)
and primary (PLLO#1) oscillators. At 1809Z orbit 11219, SOCC will command a
switch from PLLO#2 to PLLO#1 and back again. The PLLO#2 is currently
locked at the wrong frequency. This procedure should free up the oscillator
from its locked state and allow it to settle down at the proper frequency.
Since the oscillator is already warm, the settling time is expected to be
shorter. Level 1B users may see improvement within the first orbit. The
first level 1B pass affected will be:

We will continue to monitor the data and keep you informed of any changes.

Contact Person(s) Name/Email/Phone Number for Questions: ext. 117

Web site(s) that contain other relevant information (where applicable): - SOCC morning reports - History of level 1B
notices - All user notices