ˆTrunking Operation

The scanner tracks transmissions that use the Motorola Type I, Type II, hybrid, and Ericsson EDACS analog trunking systems. The frequencies for many of the 800 MHz, 900 MHz, and EDACS public safety systems are listed in the separate National Public Safety Trunked System Frequency Guide included with your scanner.

TYPES OF TRUNKING SYSTEMS

This trunking scanner monitors two basic types of sys- tems — the Motorola Type I/Type II or hybrid system, and the Ericsson EDACS system. Instead of selecting a specific frequency to transmit on, a trunked system chooses one of several frequencies in a 2-way radio us- er’s talk group when that user presses their PTT (push to talk) control. Thus, trunking systems, in general, allocate a few frequencies among many different users. Motorola Type I and Type II systems achieve the same results in a slightly different way. One important distinction between these systems is the amount of data transmitted by each radio when the operator pushes the PTT control. A Type I system transmits the radio’s ID and its current affiliation or the trunk system to which it belongs. A Type II system only transmits the radio’s ID.

Why the difference? In Type I systems, each radio in the trunk group individually transmits its own affiliation, while the trunk system maintains a database that determines each radio’s affiliation(s) in Type II systems.

Another difference between the systems is that Type I systems are arranged in a fleet-subfleet hierarchy. For example, it is possible for a city using a Type I system to designate four fleets, each with eight subfleets.

The police department, fire department, utilities group, and city administration could each be a separate fleet. The police might decide to further divide its fleet into subfleets, such as dispatch, tactical operations, detec- tives, north, south, east, and west side patrols, and su- pervisors. All the available police radios would then be assigned to one of the police subfleets, letting the police

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Trunking Operation

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Radio Shack PRO-94 owner manual Trunking Operation, Types of Trunking Systems
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PRO-94 specifications

The Radio Shack PRO-94 is a versatile and feature-rich handheld scanner that has garnered attention from both amateur radio enthusiasts and professional users alike. Renowned for its accessibility and performance, the PRO-94 serves as an ideal device for those looking to stay connected with various radio frequencies.

One of the main features of the PRO-94 is its ability to receive a wide range of frequencies. The scanner covers VHF low and high bands, UHF, and even the 800 MHz frequency range, allowing users to pick up signals from local police, fire departments, amateur radio operators, and more. This broad frequency range ensures that users can monitor diverse communications and stay informed about local events.

The scanner is equipped with an advanced trunk-tracking technology that allows it to follow trunked radio systems. This is particularly useful for monitoring state and local emergency services, as many of these organizations have migrated to trunked systems to maximize channel efficiency. The PRO-94 simplifies this process by automatically scanning through the trunked frequencies, making it easy for users to catch important dispatches without manual adjustments.

Another standout characteristic of the PRO-94 is its 200 memory channels. Users can program these channels to store specific frequencies, making quick access seamless. The scanner also supports multiple banks, allowing for organized grouping of channels, which is advantageous for users who monitor different types of services or agencies.

With its user-friendly interface, the PRO-94 includes an LCD display that shows relevant information, such as the frequency being received or the bank and channel currently in use. The keypad is designed for efficient navigation, making it straightforward to enter frequency modes and access programmed channels easily. Additionally, the scanner features priority channels, which allow users to monitor certain frequencies continuously, ensuring they do not miss critical communications.

The PRO-94 runs on AA batteries, providing convenience in terms of power supply. Its compact size and lightweight design ensure portability, enabling users to take it on the go, whether on a hiking trip or during community events.

In summary, the Radio Shack PRO-94 stands out as a robust and user-friendly handheld scanner. Its diverse frequency reception, trunk-tracking technology, extensive memory capabilities, and portable design make it a compelling choice for anyone keen on monitoring radio communications.
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