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IMSA/IAFC Frequency Coordination

The IAFC, with its communications partner the International Municipal Signal Association (IMSA), was designated in 1986 by the Federal Communications Commission as one of only four national public-safety associations certified to provide frequency-coordination services in the United States. When first selected to perform these services, the IAFC handled license applications for applicants in the fire, emergency medical and special emergency radio services. Over time, our services have expanded to include the entire public-safety pool, including 700 MHz and 800 MHz channels.

What is frequency coordination? When a public-safety entity applies for a radio license to operate a land mobile radio (LMR) communications system, the application must first be reviewed and approved by a recognized coordinator. Coordination is required when a public-safety agency seeks a new frequency or requests a change in the conditions of any technical parameter of an existing license.

Each application is reviewed to make sure the applicant is eligible for the license and the technical data is complete and accurate. Using a database containing all available frequencies and the specific rules for each frequency, the frequency coordination office ensures that the application won’t cause harmful interference to existing licensees on the same frequency (co-channel operation) or on a nearby frequency (adjacent channel operation).

Applications are processed in the order of receipt on a nondiscriminatory basis. You don’t have to be a member of IAFC or IMSA to use these frequency-coordination services.

Spectrum allocated by the FCC for public-safety LMR voice operations are spread over several disparate blocks of frequencies. Systems in operation today are commonly found in the 30–50, 150–170, 450–512, 700 and 800 MHz bands. The availability of usable channels in each band is very limited because of the number of licensees and the number of channels required to support public-safety operations. As a result, the frequency-coordination process is critical.

Coordination staffers must look at such items as height above average terrain of the transmitter (to see how far the signal will travel), power levels, types of emission, the direction of antenna radiation, control mechanisms and other technical requirements, plus a host of legal items to make sure that the applicant is eligible to hold the license. Because of the limited spectrum and the number of licensees already operating systems, it’s important that applicants consider keeping their system parameters, such as transmitter power, area of operation and base station site selection, to the minimum necessary and be willing to work cooperatively and creatively.

Often there are no frequencies available in the desired band for the desired area of operation to allow interference-free communications. When this happens, the coordination staff will contact the applicant to determine if there’s a potential to work cooperatively with existing users in the area. This may require lowering power, reducing the area of operation or sharing a frequency.

When this occurs, the coordinator will request the applicant to obtain one or more letters of concurrence from the existing licensees. The letter simply states that the existing licensee is willing to share the frequency in question with the new licensee with the provision that the new licensee doesn’t create harmful interference. Once the coordination process is complete, the coordinator shares the completed application with other public-safety coordinators and then submits the application to the FCC for licensing.

To facilitate the public-safety community’s conversion to the FCC-mandated narrowbanding deadline (see “Narrowbanding Resources” in this issue), the IAFC offers an easy one-step method to add narrowbanding emissions to your current radio license. The frequency coordination office will complete the FCC application form for you, adding the required narrowband emissions and any missing technical information in the FCC Universal Licensing Service (ULS) database pertaining to your license and making the Canadian Line A notification if applicable.

For more information on about frequency-coordination services, including the online application submittal portal, go to IMSA’s, Frequency Coordination webpage or call 401-738-2220.

Doug Aiken, chief (ret.) for Lakes Region (N.H.) Mutual Fire Aid, is the deputy executive director for the International Municipal Signal Association.

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