Potential Spectrum Interference Associated with Military Land
Mobile Radios (01-DEC-05, GAO-06-172R).
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.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-06-172R
ACCNO: A42437
TITLE: Potential Spectrum Interference Associated with Military
Land Mobile Radios
DATE: 12/01/2005
SUBJECT: Defense communications
Military radio
Radio frequency
Radio frequency allocation
Spectrum
Spectrum management
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GAO-06-172R
Washington, DC 20548
December 1, 2005
The Honorable Todd R. Platts Chairman Subcommittee on Government
Management, Finance, and Accountability Committee on Government Reform
House of Representatives
Subject: Potential Spectrum Interference Associated with Military Land
Mobile Radios
Dear Mr. Chairman:
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.1 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.2 Garage door openers and
other unlicensed devices are often referred to as "Part 15 devices."3
1 The garage door openers in question are programmed to operate at 390
MHz. However, because the technology employs a wide receiver bandwidth,
the openers are also susceptible to interference from signals in other
parts of the 380 MHz-399.9 MHz range, with a maximum interference
potential from 387 MHz to 393 MHz.
247 CFR S:15 (2004).
In response to your April 27, 2005, request, we reviewed the potential
spectrum interference caused by DOD's recent deployment of Land Mobile
Radios. Specifically, you 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. We briefed your staff on August 30, 2005,
on the results of our review. This report summarizes that information and
makes a recommendation to the Department of Defense.
Background
The electromagnetic radio frequency spectrum is the medium that enables
wireless communications of all kinds, such as mobile phones, radios, and
satellite-based services as well as low-powered consumer devices such as
advanced tire pressure gauges, remote entry devices for vehicles, and
garage door openers. As new spectrum-dependent products are developed and
deployed, the demand for spectrum, a limited resource, has escalated among
both government and private sector users. The demand for spectrum has
resulted in direction from the National Telecommunications and Information
Administration (NTIA)4 that the U.S. Government foster spectrum conserving
methods for government radio communications systems, including, for land
mobile radios, methods for "narrowbanding" those systems. In response, DOD
issued a policy that all DOD land mobile radio systems be modified or, for
new systems, procured in conformance with the NTIA "narrowbanding"
direction by 2008.5
In response to NTIA's direction to make more efficient use of spectrum,
DOD recently began rolling out new Land Mobile Radios that comply with
narrowband requirements in various military installations across the
United States. The Land Mobile Radio system is a two-way radio system that
provides communications capabilities for law enforcement, force
protection, fire, transportation management, medical duties, and first
responders on military installations. The new Land Mobile Radios are also
expected to strengthen homeland defense with such capabilities as improved
interoperability with other installations. DOD expects the Land Mobile
Radio system to operate at about 36 locations in 9 states and the District
of Columbia by the end of fiscal year 2005, and 137 installations in 28
states and the District of Columbia by fiscal year 2010.
3The Federal Communications Commission (FCC) is an independent regulatory
body that manages commercial and nonfederal spectrum use.
4The Department of Commerce's National Telecommunications and Information
Administration manages federal spectrum use.
5Narrowbanding involves the modification or implementation of devices that
require less spectrum for their operation.
Summary
Since DOD began its rollout of the new Land Mobile Radios in 2004, a
number of complaints have been reported at several locations near military
installations-notably, Eglin Air Force Base, Florida; Defense Distribution
Depot Susquehanna (DDSP) near New Cumberland, Pennsylvania; and Ft.
Detrick, Maryland. As of August 2005, manufacturers had received over
1,300 customer complaints of affected garage door openers that they
attributed to interference from Land Mobile Radios. One major manufacturer
also estimated that its distributors had received between 7,000 and 10,000
complaints. However, the extent of interference experienced by users of
garage door openers from DOD's Land Mobile Radios is difficult to quantify
because interference problems may not be reported or may be reported to
several different organizations, including garage door opener
manufacturers and retailers, government agencies, or congressional
representatives. According to DOD and garage door opener manufacturers,
the nature of the interference that has occurred varies by location. In
some locations where the radios were rolled out, no occurrences of
interference have been reported. Where interference has been reported, the
problems range from intermittent inoperability to situations where the
garage door may not open at all with the remote control device. DOD has
reported a decrease of interference complaints. They attribute this
decrease, in part, to consumer awareness of the problem and the completion
of the Land Mobile Radio testing phase, at each site.6
Because DOD is the authorized user of the 380 MHz-399.9 MHz spectrum, it
was under no obligation, according to the FCC, to identify or mitigate
potential interference with Part 15 devices that may also be operating in
that spectrum. Even if DOD had attempted to identify Part 15 devices,
there is no documentation available as to where such devices operate.
Users of Part 15 devices are not tracked by federal agencies in the way
that licensed users are tracked. DOD chose to operate the new Land Mobile
Radio system in the 380 MHz-399.9 MHz spectrum range because other bands
of spectrum could not accommodate system requirements. DOD received NTIA
certification in 2003 to operate the new radios in that spectrum.
According to DOD officials, they cannot readily move off of this range of
spectrum as it would necessitate costly technical changes and would
negatively impact Land Mobile Radio capabilities.
6According to DOD officials, the potential for interference is higher
during the testing phase when the radio system is transmitting a test tone
continuously on a single frequency.
In early 2005, following reports of interference, NTIA's Office of
Spectrum Management and the FCC's Office of Engineering and Technology
established a working group with representatives from DOD and the major
manufacturers of garage door openers to develop short- and long-term
solutions to the spectrum interference problem. The group has met several
times, and as a result, DOD and the manufacturers report that progress has
been made in terms of coordination and information sharing. For example,
DOD has provided the Land Mobile Radio rollout locations to manufacturers
and the ranges of spectrum to be affected through fiscal year 2010. DOD
has also conducted analyses showing the likely extent of potential
interference from Land Mobile Radios in several populated areas where the
radios will be deployed and has given the findings to major manufacturers.
For their part, manufacturers are offering retrofit kits to change the
frequencies of existing garage door openers that would cost consumers $50
to $80, excluding installation. Furthermore, for new devices, one
manufacturer is moving off of the 390 MHz spectrum range, and another
plans to go to a multi-frequency approach using 390 MHz and other spectrum
in order to minimize potential interference problems in the future.
Despite these efforts, for consumers with garage doors that do not
operate, it can be difficult and costly to sort out the problem and to
know how to fix it. Information available does not always provide a clear
course of action to consumers trying to remedy interference problems.
Because of potential confusion, consumers receiving intermittent
interference may unnecessarily purchase a new opener, not knowing that the
interference may be temporary. While DOD has provided guidance to local
installations regarding public relations with the communities potentially
affected by the Land Mobile Radio rollout, it is largely reactive in
nature. Specifically, the guidance primarily provides information on how
to respond to media inquiries and leaves the decision of any community
outreach efforts to the discretion of local installation officials. The
benefits of proactive community outreach were demonstrated in one
installation we visited where, among other things, installation officials
briefed retail associates, and local officials and continued to keep the
local media informed of the situation. These proactive efforts have helped
to resolve complaints, according to installation officials.
DOD officials recently acknowledged the need to improve community outreach
efforts and told us that they are planning to take steps to more
proactively inform local communities of potential interference problems.
For example, DOD and the major garage door manufacturers plan to
synchronize outreach efforts to ensure communities receive at least 1
month notification of the Land Mobile Radio rollout. DOD is also creating
press release templates for local installations to use that will include,
among other things, information about the radio system, potential
interference that could occur, and points of contact. In addition, DOD
officials plan to inform local congressional district offices as
appropriate of the potential for spectrum interference associated with the
rollout of Land Mobile Radio systems. These outreach efforts, if carried
out, should help better inform local communities that may encounter
interference problems.
Recommendation for Executive Action
We recommend that the Secretary of Defense document and affirm DOD's
current plans for improving community outreach.
Agency Comments and Our Evaluation
DOD provided written comments on a draft of this report. Their comments
are discussed below and are reprinted in appendix I. Both DOD and NTIA
provided technical comments which were incorporated where appropriate. The
FCC had no comments on a draft of this report.
DOD concurred with our recommendation and indicated that it plans to
follow through with the outreach effort. DOD noted that the responsibility
for mitigating potential spectrum interference lies solely with the garage
door device manufacturers. DOD expressed concern that the recommendation
could entail a recurring reporting requirement throughout the roll-out of
the radio system. Our intent with the recommendation, however, is not to
require DOD to report on outreach efforts each time the radio system is
fielded at a new location. Rather, the intent of the recommendation is to
have DOD formalize its current plans for improving community outreach on
future radio deployments. DOD is required, however, by 31 U.S.C. S:720 to
report to Congress on the action taken on the recommendation.
Scope and Methodology
To assess the extent of the interference problems associated with Land
Mobile Radios, DOD's efforts to identify potential interference and ways
to address it, we interviewed key officials from DOD, FCC, NTIA, and
representatives of the garage door opener manufacturing industry. We also
reviewed various DOD, FCC, and NTIA documents, reports, and guidance. To
assess responses by local installations to reports of interference, we met
with DOD officials from Ft. Detrick, Maryland and New Cumberland,
Pennsylvania. We conducted our work between June and September 2005 in
accordance with generally accepted government auditing standards.
We are sending copies of this letter to the Secretary of Defense and
interested federal agency officials and Congressional committees. We will
make copies available for other interested parties upon request. In
addition, the letter will be available at no charge on the GAO Web site at
http://www.gao.gov.
Please contact me at (202) 512-4841 if you or your staff has any questions
concerning this letter. Other major contributors to this letter were John
Oppenheim, Ridge Bowman, and Lisa Henson.
Sincerely yours,
Paul L. Francis, Director Acquisition and Sourcing Management
Enclosure: Comments from the Department of Defense
(120465)
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