INTERFERENCE TO GPS RECEIVERS FROM CONSUMER ELECTRONICS-GRADE ACTIVE VHF/UHF MARINE TELEVISION ANTENNAS

[Sam Wormley]

Ref: http://www.navcen.uscg.gov/NOTICE%20TO%20MARINERSfccREV.htm

INTERFERENCE TO GPS RECEIVERS FROM CONSUMER ELECTRONICS-GRADE
ACTIVE VHF/UHF MARINE TELEVISION ANTENNAS

It has come to the attention of the U.S. Coast Guard and Federal Communications
Commission that certain consumer electronics-grade active VHF/UHF marine
television antennas are causing operational degradation in the performance of GPS
receivers. This interference may be realized as a display of inaccurate position
information or a complete loss of GPS receiver acquisition and tracking ability and
the interference interactions have been reported up to 2000 feet from the
interference source. This interference has been associated in some instances with
temperature extremes or proximity to a television broadcast site.

If you are experiencing recurring outages or degradation of your GPS receiver you
should perform an on-off test of your TV antenna. If turning off the power to the
antenna results in improvement in the GPS receiver performance, the antenna may
be the source of interference in the GPS band. In that case, you should contact the
manufacturer of the antenna and identify the symptoms. If the test is not positive
and the GPS interference persists, you may contact the Coast Guard, Office of
Spectrum Management via email at CGC...@comdt.uscg.mil or through the
Coast Guard Navigation Information Service at

703-313-5900/email: ni...@navcen.uscg.mil.