The U.S Department of Defense submitted a report to Congress today that identifies a limited possibility of sharing the department’s frequencies in the 138MHz–144MHz band.

The frequencies would be shared with state and local governments for use by public safety agencies, which the department calls “first responders.” A Department of Defense Joint Spectrum Center engineering study identified ways sharing would be possible without interfering with Department of Defense operations.

It isn’t certain whether the public safety community will view the report as evidence of substantial progress toward frequency sharing. Members of the Spectrum 138-144 MHz Subcommittee of the National Public Safety Telecommunications Council who met during the APCO National Conference in Salt Lake City last August explained that the military tends to view sharing in terms of short periods of time, whereas public safety agencies want to share frequencies indefinitely in locations where their operations would not interfere with military radio systems.

The subcommittee’s chairman, Vincent Stile, noted that the Department of Defense report is classified and, as such, is not yet available to the general public. He described the department’s announcement as “encouraging.”

Stile said that the subcommittee gave its interpretation of sharing to the National Telecommunications and Information Administration, which assigns frequencies to federal users, including the military.

“I feel the Department of Defense does know what is meant from our side. These are extremely difficult times for all involved in spectrum management, and each needs to respect each other's position. But sharing is possible with good engineering and safeguards. The [Spectrum 138-144 MHz Subcommittee] is ready to work with the Department of Defense as soon as possible,” Stile said.

Deputy Assistant Secretary of Defense for Spectrum and C3 Policy Steven Price said, "We believe it is possible to share portions of the 138MHz–144 MHz band with public safety users on a limited, coordinated basis. The Department of Defense is willing to work with National Telecommunications and Information Administration, state and local governments and first responders on a case-by-case basis to explore sharing the band for the common good."

A prepared statement from the Department of Defense said that, although the 138–144 MHz band continues to be critical to its operations, the department has found it helpful in emergencies to share communications systems with other first responders. A small number of channels may be shared on a regional basis when it is to the mutual benefit of the department and public safety officials.

“Department of Defense operations that would be affected if this band were interrupted through heavy use of too many channels would include air-surface-air, air traffic control and ground support functions at military airfields, tactical communications for close air support, land mobile radios for sustaining installation infrastructure support and land mobile radios and specialized equipment for training and test range support. Other systems that would be affected include fire and security alarms, and hydrology and utility controls,” the statement reads.

The Department of Defense statement explained that the National Defense Authorization Act for fiscal 2000 reclaimed 3MHz of spectrum in the 138-144 MHz band for reallocation for mixed federal government and non-federal government uses. The largest federal user would be the Department of Defense. The reallocation is subject to to requirements of the Balanced Budget Act of 1997.

The Department of Defense takes the position that Congress understood that the recovery of 3 MHz of spectrum “was and is crucial to fulfilling DoD's spectrum requirements.” Nevertheless, in the conference report, the Department of Defense was asked to provide a technical report assessing the feasibility of sharing the 138MHz-144MHz band with public safety users.

In the fiscal 2001 authorization, Congress directed the Department of Defense, in cooperation with the Justice Department and the NTIA, to provide for an engineering study with regard to spectrum sharing in the 138MHz-144MHz band. The assistant secretary of Defense for Command Control Communication and Intelligence (C3I) has submitted this report to the Senate Armed Services Committee and the House Armed Services Committee.

“Under direction of Assistant Secretary of Defense for Command, Control, Communications and Intelligence (C3I) John Stenbit, the Department of Defense Joint Spectrum Center conducted an engineering study regarding sharing in the 138MHz-144 MHz band. The resultant classified study showed that the areas of operation associated with the Department of Defense frequency usage in the 138MHz-144 MHz band encompasses nearly the entire continental United States. Large distance separations would be required to prevent co-channel and adjacent-channel interference between Department of Defense equipment and potential state and local public safety systems, particularly in the case of Department of Defense air-ground-air radios,” the statement issued by the department reads.