GBT Observing Alerts

Expected RFI from GPS at 1381.5 MHz

We have just received the following notices from Daniel J. Mertely of NRAO-Socorro that we should be seeing RFI at 1381+/- 2.5 MHz on the dates and times listed below. Extragalactic HI projects that plan to observe around z~0.03 may be affected. Galactic HI projects, or extragalactic projects with either much smaller (< 0.02, say) or larger redshifts (> 0.04) should be OK.

We have been pre-alerted to the following, military GPS-L3 test Transmissions which may cause RFI to observations scheduled for the use of L-band (21cm) on the UTC date(s) and time(s) listed below. These tests are related to the periodically scheduled "RZAPS/LZAPS" tests of the GPS satellite system.

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DATE (UTC) TIME (UTC) Comments
(YYYYMMDD) (HHMM)-(HHMM) (TEXT)
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20090915 1900 - 2400 RZAP/LZAP system-wide tests (Primary).
20090916 0000 - 0300 RZAP/LZAP system-wide tests (Primary).
20090916 1900 - 2400 RZAP/LZAP system-wide tests (Back-up).
20090917 0000 - 0300 RZAP/LZAP system-wide tests (Back-up).
20090917 1900 - 2400 RZAP/LZAP system-wide tests (Back-up).
20090918 0000 - 0300 RZAP/LZAP system-wide tests (Back-up).

20091201 2000 - 2400 RZAP/LZAP system-wide tests (Primary).
20091202 0000 - 0500 RZAP/LZAP system-wide tests (Primary).
20091202 2000 - 2400 RZAP/LZAP system-wide tests (Back-up).
20091203 0000 - 0500 RZAP/LZAP system-wide tests (Back-up).
20091203 2000 - 2400 RZAP/LZAP system-wide tests (Back-up).
20091204 0000 - 0500 RZAP/LZAP system-wide tests (Back-up).
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