The Cumberland Mountains in Cumberland County, Tenn., present a challenging terrain for radio communications. The same peaks and valleys that make the area inviting to vacationers, golf enthusiasts and residents hinder conventional analog public safety radio communication.

In 2006, Cumberland County's Emergency Services Committee — representing the sheriff's department, correction facility, fire department, rescue squad, emergency management agency and emergency medical services — decided to replace the area's multiple VHF radio systems with a system with expanded coverage that its agencies could use to reliably communicate with each other. The committee determined that a digital trunked radio system would best meet its needs because it would more efficiently use the available radio spectrum, and have more features and better security than the county's previous system. In 2007, the county contracted with Frisco, Texas-based EADS Secure Networks to design and deploy the system.

The county's new network, which was fully adopted this summer, consists of five sites — each with a tower, radio transmitters/receivers and other network equipment — and four channels (one control and three voice). The system complies with the Association of Public-Safety Communications Officials Project 25 (P25), making it compatible with the existing analog radio system and capable of communicating with neighboring networks through a standard interface. It works with the county's existing radio equipment, including its 911 call-taking and transfer system, and subscriber units (radios) manufactured by Kenwood.

Dispatchers now have radio access to both the P25 UHF network and the VHF conventional networks, so each agency can move to the new network on its own schedule. The new system has increased service coverage from 80 to 95 percent of the county's terrain.

Project: Public safety radio network upgrade
Jurisdiction: Cumberland County, Tenn.
Agency: Emergency Services Committee
Vendor: Frisco, Texas-based EADS Secure Networks
Date completed: July 2009