US Coastguard Warning of GPS degradation

Created by doina. Last modified on 2003-01-03 10:50:03
Contributors: Val Ellis, Noonsite
Topic: Communications

Released 01 January 2003

The U.S. Coast Guard warns mariners that some marine television antennas may result in inaccurate position information or loss of GPS signals. Interference is not necessarily limited to GPS equipment on board the vessel with the antenna, but could affect craft some distance away.

The Federal Communications Commission has identified the following models of antennas as having potential problems affecting GPS: Tandy Distribution Products Electronics, MINI STATE Electronic Amplified UHF/VHF TV Antenna – Models 5MS740, 5MS750, 5MS921; Radio Shack Corporation, Long Range Amplified Omni Directional TV Antenna – Model 15-1624; Shakespeare Corporation SeaWatch – Models 2040. The Coastguard is, however, stressing that the problem may occur with other antennae.

Any mariner, with a marine TV antenna, experiencing a lack of signal or degradation of GPS operation, should perform a test. If turning off power to the TV antenna results in improvement in GPS performance, the mariner should contact the manufacturer of the antenna and identify the symptoms. If the antenna is not listed above, or if switching off a TV antenna does not improve performance, the Coast Guard requests that mariners contact the Navigation Information Service at nisws@navcen.uscg.mil