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Potential Spectrum Interference Associated with Military Land Mobile Radios

GAO-06-172R Published: Dec 01, 2005. Publicly Released: Dec 01, 2005.
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To address homeland defense needs and comply with government direction that agencies use the electromagnetic spectrum more efficiently, the Department of Defense (DOD) is deploying new Land Mobile Radios to military installations across the country. The new Land Mobile Radios operate in the same frequency range--380 Megahertz (MHz) to 399.9 MHz--as many unlicensed low-powered garage door openers, which have operated in this range for years. While DOD has been the authorized user of this spectrum range for several decades, their use of Land Mobile Radios between 380 MHz and 399.9 MHz is relatively new. With DOD's deployment of the new radios and increased use of the 380 MHz-399.9 MHz range of spectrum, some users of garage door openers have experienced varying levels of inoperability that has been attributed to interference caused by the new radios. Nevertheless, because garage door openers operate as unlicensed devices, they must accept any interference from authorized spectrum users. This requirement stems from Part 15 of the Federal Communications Commission (FCC) regulations. Garage door openers and other unlicensed devices are often referred to as "Part 15 devices." Congress requested that GAO review the potential spectrum interference caused by DOD's recent deployment of Land Mobile Radios. Specifically, Congress asked us to (1) determine the extent of the problem of spectrum interference associated with the recent testing and use of mobile radios at military facilities in the United States, (2) review the efforts made by DOD during the development of its Land Mobile Radio system to identify and avoid spectrum interference, and (3) identify efforts to address the problem.


Recommendations for Executive Action

Agency Affected Recommendation Status
Department of Defense The Secretary of Defense should document and affirm DOD's current plans for improving community outreach.
Closed – Implemented
DOD concurred with our recommendation. In early 2006, DOD distributed information packages to service public affairs offices which provided guidance regarding community outreach. The packages included, among other things, Land Mobile Radio roll-out schedules, a draft press for informing local communities, a draft email for informing individual installation public affairs offices, and a copy of our 2006 report.

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Defense communicationsMilitary radioRadio frequencyRadio frequency allocationSpectrumSpectrum managementMobile radioConsumer complaintsMilitary facilitiesCommunities