800MHz

The following information and pictures show typical installations at the 800MHz sites.

When the final contract was in place it had some clauses that Motorola had some concerns about. The system had to give 97% mobile coverage 100% of the time, and the state would not pay anything until first phase was up and running and passed coverage test.

The entire state was divided into 2 X 2 mile grids. The audio quality of both transmit and received signals were tested by an officer with a moving mobile unit in each grid and had to receive a Circuit Merit 3 signal (minimum). 97% of all grids had to pass - no two contiguous grids could fail.
(Grid Testing)

Original installation consisted of 181 sites throughout the state and when completed it was to be maintained by MSP radio technicians. As of January 2009 the state had 223 tower sites to watch plus another eight scheduled to come on line by the end of the year.

All sites run on electrical power supplied by local power company. A gas, (Propane) generator takes over if electrical power is lost. An uninterruptible power supply large enough to hold the site in operation until generator starts and comes up to speed. This keeps the site 100% active with no down time. The UPS will keep the site in operation for at least one hour incase of a generator malfunction, normally enough time for service personnel to get to the site to investigate.

The entire radio system is monitored at a Network Control Center with alarms on almost every piece of equipment at each site.

Above are pictures of equipment found at every site. The UPS size is dependent on how much equipment needs to be backed up, some sites could have 4 to 12 or more Intel repeaters and 2 to 6 microwave units. Sites are kept at 72 degrees, but just incase note the emergency air vent.

All sites are have same equipment lay out with microwave and associated equipment in the right racks and the 800MHz Intel Repeaters and it's associated equipment in the left racks. Picture on right is Intel Repeaters with Mutual Aid as top unit. All sites were built with the ability to expand for addition of more equipment, doghouses near large population areas are larger then those in remote less populated areas.

In addition to digital Intel Repeaters every site has an analog repeater called Mutual Aid. This is on a common frequency that any agency that has their own 800MHz system even from out of state can have communications while visiting or in pursuit across state lines.

As one can imagine, the design, site location, property acquisition, frequency coordination, equipment choices, training, building of sites and towers and so much more were not a simple thing to take on.

The state runs an intensive preventive maintenance program, above is Charles, not sure if he is working or on coffee break, but it can be seen he has test equipment and computer set up to do microwave testing. Charles is one of several that came into MSP communications before it was all moved to Department of Information and Technologies. If you have any questions go to Web Master and get my E-mail address.

Typical post desk setup for dispatching and handling of all information needed by patrol cars. This happens to be the desk at Jackson, MI.

Typical installation in trunk of patrol cars. This one happens to have the 800MHz radio and siren box mounted on top with a high band Syntor X mounted to the right for local area work with county at Jackson, MI. Below is the control heads and associated equipment between front seats of same vehicle.

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