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entitled 'Potential Spectrum Interference Associated with Military Land 
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Washington, DC 20548: 

December 1, 2005: 

The Honorable Todd R. Platts: 
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.[Footnote 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.[Footnote 2] Garage door openers and other unlicensed 
devices are often referred to as "Part 15 devices."[Footnote 3] 

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 


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)[Footnote 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.[Footnote 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 


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.[Footnote 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. 

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. 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 

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, 

Signed by: 

Paul L. Francis, Director: 
Acquisition and Sourcing Management: 

[End of section] 

Enclosure: Comments from the Department of Defense: 

WASHINGTON, DC 20301-6000: 

Mr. Paul L. Francis: 
Director, Acquisition and Sourcing Management: 
U.S. Government Accountability Office: 
441 G Street, N.W.: 
Washington, DC 20548: 

November 23, 2005: 

Dear Mr. Francis: 

This is the Department of Defense (DoD) response to the GAO draft 
report, "Potential Spectrum Interference Associated with Military Land 
Mobile Radios" dated October 20, 2005 (GAO Code 120465). DoD concurs 
with on this report with the understanding that there will be no 
reporting requirement on the recommendation. Enclosed are specific 
comments to the report. 


Signed by: 

Badri A. Younes: 
Director, Spectrum Management: 


GAO CODE 120465/GAO-06-172R: 




The GAO recommended that the Secretary of Defense document and affirm 
its current plans for improving community outreach. (p. 5/GAO Draft 

DOD RESPONSE: Concur with recommendation with the following 

As discussed with the GAO, the intent of the recommendation is not to 
impose a reporting burden on DOD or to require DOD to report on 
outreach efforts each time a radio system is fielded to a new location. 

The Department is currently developing and executing a community 
outreach campaign. This campaign is a subset of the collective effort 
that the Department has undertaken to address this issue. In a 
traditional scenario, the responsibility for addressing an interference 
situation between a licensed and unlicensed user would fall completely 
on the unlicensed user. Although not obligated to do so, the Department 
has assisted the unlicensed device manufacturer, or service provider, 
in addressing this interference situation by sponsoring technical 
studies and sharing implementation information. 

The Federal Communications Commission (FCC) and the National 
Telecommunications and Information Administration (NTIA) regulate the 
government and non-government radio spectrum and this situation falls 
within regulations in which FCC and NTIA govern. The primary 
responsibility should be placed on these institutions. Since a licensed 
user is causing interference to these unlicensed devices, the 
responsibility lies solely on the unlicensed device manufacturer to 
provide for mitigation. 

The Department will continue to assist unlicensed service providers, in 
this case, garage door manufacturers, in addressing the issue to 
continue the Department's traditionally harmonious relationship with 
its surrounding communities. This includes the recommended outreach 
campaign, however, the Department takes issue with there being a formal 
reporting requirement placed on the licensed user, and not on the 
responsible parties, the unlicensed device manufacturer, as well as the 
relative regulators, the FCC and NTIA. The Department's roll out of 
land mobile radio (LMR) equipment in this bandwidth is currently 
planned to extend through the year 2010; imposing reporting 
requirements throughout this time period is unacceptable and 
unnecessarily burdensome. 

The Department's position is that this recommendation be removed, since 
its removal will not impact the Department's plans to assist in the 
resolution of this matter. The Department can concur with the 
recommendation with the understanding that there will be no reporting 
requirement on its status. 

As stated above, the Department will continue to support its resolution 
to the maximum extent possible. 

[End of section] 


[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. 

[2] 47 CFR 15 (2004). 

[3] The Federal Communications Commission (FCC) is an independent 
regulatory body that manages commercial and nonfederal spectrum use. 

[4] The Department of Commerce's National Telecommunications and 
Information Administration manages federal spectrum use. 

[5] Narrowbanding involves the modification or implementation of 
devices that require less spectrum for their operation. 

[6] According 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.