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Re:Need Police Scanner Freqs - 2005/09/08 23:38
If you are in a trunking area:
Trunking is the capability for a local government to purchase (for example) six frequencies instead of twenty-six. Each radio has a 'talkgroup' programmed into it. It has been programmed to only listen to certain talkgroups. When a police officer keys up his mic, it requests a channel. If there is a free channel available then the channel that currently has the clearest reception out of those available is designated to that radio. All other radios that have been programmed to listen to that particular one also change to the new frequency and listen. If no frequency is available, then a hierarchy of importance is used. Generally, life support gets precedence over police. For example, if an officer is communicating, and there is a major fire or triage event, all of the radios that are related to saving lives will cause the control computer to kick off the police officers until there is a free frequency available at that authorization level.
Unlike the old way of each public safety department (fire, police, water, sewer) having their own broadcast frequencies, now they each share a few of them. A main control computer determines who will use which frequency at any given moment.
A normal (cheap) scanner can still follow these communications, provided it is capable of receiving the higher band frequencies. You do need a trunking capable scanner to predict what you will hear. It will allow you an easier method of following police, fire, etc. and possibly separately.
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