[Note: The following is excerpted from the ARRL Repeater Directory.]
The ARRL is not a Frequency Coordinator, nor does the ARRL "certify" coordinators. Frequency Coordinators are volunteers normally appointed by a coordinating body. The ARRL reports only the fact of coordination or non-coordination as instructed by the coordinating body. Publication of coordinator information by the ARRL does not constitute nor imply endorsement or recognition of the authority of such coordinators, as coordinators derive their authority from the voluntary participation of the entire amateur community in the areas they serve. Frequency Coordinators keep extensive records of repeater input, output and control frequencies, including those not published in directories (at the owner's request). The coordinator will recommend frequencies for a proposed repeater in order to minimize interference with other repeaters and simplex operations. Therefore, anyone considering the installation of a repeater should check with the local frequency coordinator prior to such installation.
View the listing of groups or individuals for the United States who are active in Frequency Coordination and are acknowledged, by virtue of the recognition accorded them by the entire amateur community they serve, as the sole Frequency Coordinator in their respective jurisdictions.
Click here for the National Frequency Coordinators Council website.