800 mhz freq

[svrablic]

Having a hard time locating 800 Mhz Frequencies for Law Enforcement in Michigan, Specifically county and State Police, I located the list of talk groups for the State and County Law enforcement but can't find specific 800 Freqs.

 

[ecps92]

Michigan's Public Safety Communications System (MPSCS) Trunking System, Statewide, Multi-State - Scanner Frequencies
Pick your nearest Tower to start with

Having a hard time locating 800 Mhz Frequencies for Law Enforcement in Michigan, Specifically county and State Police, I located the list of talk groups for the State and County Law enforcement but can't find specific 800 Freqs.

 

[svrablic]

How do I decipher which frequently goes with which talk group?

 

[n5ims]

Having a hard time locating 800 Mhz Frequencies for Law Enforcement in Michigan, Specifically county and State Police, I located the list of talk groups for the State and County Law enforcement but can't find specific 800 Freqs.

If your agency's database page lists talkgroups, there won't be a single frequency listed. There will a pool of frequencies that all talkgroups will share as needed. This is what is known as a "Trunking Radio System". A good description of trunking is in the RR Wiki here --> Trunked Radio Systems - The RadioReference Wiki

As already indicated, there is a statewide system in your area that many PD agencies use. You'll need to find the site for your area and program in those frequencies for your scanner to use. Next, you should program in the talkgroups for the agency or agencies you are interested in. This will allow you to easily see who is talking (for example, you may see "My City PD Dispatch" instead of "39459").

With the correct software and a premium subscription to RadioReference, you can often save time and trouble by downloading your trunking system(s), site(s) and talkgroups. Some scanners have their own software and build-in SD-Card memory to make it even easier to get started (but this won't be all that customized) where all you may need is your local zip code.

 

[ofd8001]

There are also a number of excellent YouTube videos explaining the basics of trunked radio systems. One of these describes the Minnesota radio system, which is similar to the Michigan system in that they are both statewide radio systems. https://www.youtube.com/watch?v=OMT4gHXmTVw

Also, assuming you are new to the hobby, not just any scanner is capabile of monitoring the Michigan system. The scanner must be a digital trunked scanner.

 

[DickH]

How do I decipher which frequently goes with which talk group?

This will give you a basic understanding of how a trunked system freqs. and Talk Groups work.
MOTOROLA TRUNKING (most common)

The object of trunking is to allow many users to share a relatively few frequencies.
A trunking system is controlled by a computer. Information (data) is exchanged between the system radios and the computer on a control channel, sometimes called a data channel. It sounds like a strong buzz.

A large system can have up to 28 freqs., 4 of which may be used as control channels. The control channel may be changed once a day or as often as the programmer decides. Some scanners need only the control channels to track an entire system. Just put in all the Control Channels.

Each group of users (Fire, Police, etc.) is assigned TALK GROUPS. In a Motorola Type II system, the most common type, TGs are usually in 32 number steps starting with 16 and going up to 65536; 16, 48, 80 --- 4656, 4688, 4720 --- 28944, 28976, etc. System radios can have more than 100 TGs programmed into them.

Digital systems are similar, but the talk groups use every number (like 2491, 2492, 2493, etc.).

When a user pushes the talk button on his radio, data is sent to the computer. The computer chooses an unused freq. and sends that data to all the radios using the TG of the originating unit. This all happens in a fraction of a second and it happens EVERY TIME a radio is used.

EXAMPLE:
Fire Dispatch calling Engine 4 (TG 4528 on 856.7125)
Engine 4 answering Dispatch (TG 4528 on 852.2625)
Respond to 73 Elm Street (TG 4528 on 855.9625)
Engine 4 responding (TG 4528 on 851.6375)

If you have entered TG 4528 into your scanner, it will decode the control channel data and change your scanner freqs. to follow the conversation on TG 4528.