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The fleets might be the police department, the fire de- partment, utilities, and city administration. The police might decide to further divide its fleet into subfleets such as dispatch, tactical operations, detectives, north, south, east and west side patrols, and supervisors. All the avail- able police radios would then be assigned to one of the police subfleets, letting the police centralize their com- munications and control the type of users on a single system. Determining the exact fleet-subfleet hierarchy for a particular area is referred to as fleet map program- ming.

The disadvantage of a Type I system is that the brief burst of data sent when a user transmits must contain the radio’s ID and its fleet and subfleet. This is three times the amount of data a Type II system radio sends. Since the data capacity of Type I systems is limited and the amount of data increases with each user, Type I sys- tems usually accommodate fewer users than Type II systems. Nevertheless, Type I systems are still in use.

There are also hybrid systems which are a combination of both Type I and Type II. Your scanner defaults to monitor Type II systems, but you can change to Type I or a hybrid of Type I and Type II systems by selecting a preprogrammed fleet map or creating a custom fleet map for your area (see “Scanning Type I and Hybrid Trunked Systems” on Page 44).

You do not need to determine the fleet-subfleet hierar- chy for Type II systems unless you are tracking hybrid systems that contain both Type I and Type II systems.

SETTING THE SCANNER TO THE TRUNK TRACKING MODE

Repeatedly press TRUNK to switch between the scan- ner’s conventional and trunk tracking modes.

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Radio Shack PRO-90 owner manual Setting the Scanner to the Trunk Tracking Mode

PRO-90 specifications

The Radio Shack PRO-90 is a compact yet powerful handheld scanner that has garnered attention from both hobbyists and serious enthusiasts of radio communications. Introduced as a versatile scanner, the PRO-90 is designed for ease of use while providing a myriad of features that enhance the scanning experience.

One of the key characteristics of the PRO-90 is its advanced scanning technology. The unit boasts a 100-channel memory, allowing users to store and quickly access frequently used frequencies. The scanner supports a wide range of frequency bands, making it suitable for monitoring everything from police and fire frequencies to aviation and marine channels. With programmable scanning capabilities, users can effortlessly create their own scanning routines tailored to their interests.

The PRO-90 also features a fast scanning rate, with the ability to scan across frequencies at remarkable speeds. This minimizes the wait time for users who want to listen to different bands or channels, ensuring they never miss critical transmissions. Additionally, the scanner includes a dedicated "Hold" function that allows users to temporarily pause on a specific frequency for extended listening.

In terms of ease of use, the PRO-90 is designed with an intuitive interface. The scanner includes a backlit LCD display, making it easy to read in low-light environments. The keypad is arranged logically, enabling quick access to functions such as volume, squelch, and memory management. Users can also program the scanner via PC, thanks to its compatibility with programming software, making it easier to manage and transfer frequency lists.

Another standout feature of the PRO-90 is its ability to decode various digital signals. This includes some types of Motorola, GE, and other digital technologies, which are commonly used in modern communications. This capability extends its usefulness beyond traditional analog signals, making the scanner relevant in today’s digital landscape.

Moreover, the Radio Shack PRO-90 is designed with portability in mind. Its compact size and lightweight construction make it an ideal companion for outdoor activities, road trips, or simply enjoying the local communications landscape. Whether you’re a seasoned radio enthusiast or a newcomer to the field, the PRO-90 provides a rich set of features, advanced technology, and user-oriented design that enhance the scanning experience. It stands out as a worthy tool for anyone looking to immerse themselves in the world of radio communication.