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Hamilton County Digital Communication Network, United States of America

Key Data

In May 1999, Hamilton County, Ohio took its first steps into digital communications. It approved spending $4.9 million for a limited 800MHz emergency communication system. The commissioners budgeted $6 million to buy radios for about 40 of Hamilton's county fire and ambulance services. The contract was awarded to Motorola, due to its low bid, and all other fire and ambulance services in the county will have at least one of the digital radios. Police agencies are not to be part of the system. The radios were installed at the end of summer 1999, enabling fire and emergency management services to go on line. The second phase of the project is to provide the infrastructure to support police and mobile radio communication.

In February 2001, a further contract was awarded to Motorola to design and install a countywide 800MHz digital communications system, enabling more than 100 public safety agencies and local government entities to talk directly with each other for the first time. It will also provide better communication during emergencies as it will not get jammed with radio traffic and will penetrate areas of the county the current system cannot. The $19 million communications system will be used by county public safety agencies - including police, fire and emergency medical services - throughout Hamilton County. The system's capability will also be available to other local government public service entities, including the county engineer and Metropolitan Sewer District, to improve day-to-day communications and operations. The infrastructure for the system was complete in 2002, and as funds become available over the next seven years, law enforcement and public works will be integrated.


The system to be installed will be the new Motorola Astro25 Smartnet digital system, which complies with the Common Air Interface (CAI) included in Project 25 digital standards for communications systems. Project 25 is the functional and technical standard for public safety digital systems adopted in 1995 by a consortium of two-way radio user groups to ensure that public safety personnel would be able to communicate directly with each other. The system uses nine Motorola Centracom Gold Series consoles installed at the main dispatch centre for the county. County officials project approximately 3,500 Astro xts 3000 digital portable radios and Astro Spectra mobile radios will be incorporated into the system over a three-year period. The 15 site system will include 20 channels and use simulcast technology to enhance communications coverage throughout Hamilton County, which has a population of about 850,000 people and includes the city of Cincinnati. The individual system sites are connected by a digital microwave system. The simulcast feature means the system will transmit each message at the same time from all sites.


The system will give interoperability with agencies around the county that was not possible before. This will enable the county to co-ordinate communications rapidly and efficiently. The technology will help enhance coverage in previously hard to reach areas (such as inside buildings) making it easier to communicate in emergency situations requiring multi-agency response. The technology included in this digital system will provide Hamilton County with the interoperability and other features and capabilities it will need to address changing communications needs for years to come.