VLBA RFI Bulletin 21:  GPS-L3 Downlinks Scheduled for Early December

GPS-L3 RFI ALERT. . . GPS-L3 RFI ALERT. . . GPS-L3 RFI ALERT.
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The US Space Command (SpaceCom) has announced a series of GPS-L3
downlinks for early December, 1998.  The increased use of the L3
(1381.04 MHz) frequency is the result of heavy data downlinks required
to test system parameters.

SpaCecom has indicated that their usage of the 1381.05 MHz GPS-L3
frequency will be extra heavy during the Friday, 9871204 and Saturday,
981205 UTC dates.

Their planned duty cycle is as follows:  In addition to the standard,
daily calibration data bursts, they will be downloading special test
data every half hour, for approximately 6 minutes throughout the two
days of the test.

Expect increased likelihood of 1381 MHz RFI during these days
throughout the world.  Plots of the entire L-band spectrum from
1250 MHz to 1750 MHz are available on-line at:

	http://www.nrao.edu/vla/interference/gsplots

Select the "SATK_gs_yyyymmdd.ps" file for the day of interest.  The