Radio Scanner Guide
Part 3A: Land-Mobile Radio Systems
Police, Sheriffs, Highway Patrol, other law enforcement, fire departments, road maintenance, other local government, utilities, taxis, tow trucks, news media, and other businesses are all classified as land-mobile services. They use their radios primarily to communicate between officers or agents in the field and with the dispatcher. Public Safety and Business users are allocated frequencies in the following land-mobile radio bands: 25-50, 150.8-161, 450-470, 851-869, and 935-941 MHz. These radio bands are shown in dark green in the radio spectrum diagram below.
Types of Radio Systems:
There are four main types of radio systems your local police, fire, and emergency services may be using. The type of system used will determine which features you need in your scanner, and therefore, which of the six scanner categories you should browse through to find a suitable radio. The information is summarized in a chart at the bottom of this page.
Conventional, Analog System without 800 MHz - Conventional systems assign certain users or functions to each frequency and often the frequencies are given channel numbers. For example, the police department may have five frequencies, the fire department another five, and so on. The police department would only use its own frequencies - you would not hear police deputies on fire channels or vice-versa (except, of course, for inter-agency communications.) Conventional systems not using the 800 MHz band (i.e. systems in the 30-50, 150-162, and 450-470 MHz bands) can be monitored using scanners in any category. Category 1: Budget Scanners and Category 2: Conventional Scanners Without 800 MHz contain the least expensive radios since they lack other features like 800 MHz or trunking. Click here for more information on Conventional systems.
Conventional, Analog System with 800 MHz - As above, except your agency uses frequencies in the 800 MHz radio band (repeater outputs between 851-869 MHz). Any scanner in the following categories will work: Category 3: Conventional Scanners With 800MHz, Category 4: Analog Trunking Scanners, Category5: Digital Trunking Scanners, or Category 6: Continuous Coverage Scanners. Category 3 radios will generally be the least expensive since they lack other features like trunking. Click here for more information on Conventional systems.
Analog Trunked System - These systems share a pool of frequencies among a large group of users. Users or agencies are not assigned certain frequencies on a permanent basis, but instead are given frequencies on an ad-hoc basis each time they transmit. The purpose of these systems is to conserve frequencies - most users do not transmit continually. Systems in this group include Motorola Type I, Type II, and Type I/II hybrid systems, EDACS systems, and LTR systems. To find a scanner, look in Category 4: Analog Trunking Scanners and Category 5: Digital Trunking Scanners. Note that scanners in Category 4 tend to be less expensive since they receive only analog but not digital systems. Click here for more information on Trunked systems.
Digital (APCO-25) Conventional or Trunked System - Digital voice modulation is usually used with certain trunked systems, but may also be used in conventional mode. Either way, a scanner that can demodulate digital audio is needed. For digital systems using APCO Project 25 (APCO-25) digital format, Check Category 5: Digital Trunking Scanners. At the time of this writing, the few radio systems using other digital formats can not yet be received on scanners. Click here for more information on Digital Radio.
The following chart shows which scanner categories may be used to monitor each type of radio system. You may follow the links in the chart to view scanner models in that category, or follow the links at the bottom of this page to continue reading the site in order, to read more about other listening topics, and to read more about features to look for in a scanner.
* Scanners in Category 3 will receive 800 MHz conventional systems and will receive the audio on analog trunked radio systems, but cannot track conversations on trunked systems as they move across frequencies.