Understanding Trunking | Radio Shack PRO-92 guide

codes in the ID memory (see “Storing Talk Group IDs” on Page 55). To listen to the transmission, the mode of the programmed channel must be the same as that of the trunking channel (LT, MO, or ED).

When an ID code is received, the ID list for the bank is searched, and if found, the text name stored for the ID appears. If not found, scanning resumes immediately unless the bank is in open trunking mode.

Note: There might be more than one talk group transmit- ting at a time in some Motorola trunking systems. If you set the scanner to manually tune in Motorola trunking mode, you will hear the talk group on that channel, but the display will alternate between all active IDs.

Trunking group frequencies are included in the supplied Police Call Trunking Guide. Frequency fleet map and talk group information is also widely available on the In- ternet, at www.trunkscanner.com for example.

UNDERSTANDING TRUNKING

In the past, groups that transmit frequently, such as po- lice departments, could transmit on only a few frequen- cies. This resulted in heavy traffic and often required 2- way radio users to wait for a specific frequency to clear before transmitting. Trunked systems allow more groups of 2-way radio users to use fewer frequencies. Instead of selecting a specific frequency to transmit on, a trunked system chooses one of several frequencies when the 2- way radio user transmits. The system automatically transmits the call on that frequency, and also sends a code that identifies that 2-way radio user’s transmission on a control channel.

This scanner lets you easily hear both the call and re- sponse transmissions for that 2-way radio user and therefore follow the conversation. For EDACS and Motor- ola (above 806 MHz range), the scanner monitors the control channel between each transmission to identify talk groups. For some Motorola (under 512 MHz range) and LTR systems, the scanner uses the subaudible data sent with each transmission to identify talk groups.

Trunking Operation

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Radio Shack PRO-92 owner manual Understanding Trunking

Contents

PRO-92 Handheld Scanner Contents Operation Special Features Care Specifications TroubleshootingTrunking Operation General Guide to Scanning Features Scanner scans Features Scanning Legally FCC Notice Preparation Power Sources Using Batteries Preparation11 Replace the cover Charging Rechargeable Batteries Using AC Power PWR DC 9V jack Using Vehicle Power Connecting an Optional Antenna Connecting the Antenna Listening Safely Connecting AN EARPHONE/ Headphones Using the Belt Clip Connecting AN Extension SpeakerTraffic Safety About Your Scanner Connecting the Clone Cable Look AT the Keypad About Your Scanner Look AT the Display Understanding Banks 7 are turned off Search ModeChannel Storage Banks Search Banks Understanding CTCSS/DCSPL Codes DPL Codes Open and Closed Modes Understanding Your SCANNER’S Modes AM Mode LTR E. F. Johnson Mode FM Mode Motorola Mode Edacs Mode Operation Turning on the Scanner and Setting Squelch Bank Channel Manual Storing Known Frequencies Into Channels Assigning a Text Tag to a Channel Storing Text Tags Assigning a Text Tag to a Bank Press To Enter a Character from this Group Text Input Chart Searching a Preprogrammed Frequency Range Finding and Storing Active FrequenciesPress Func 9 w x y z Current Search Bank Changing a Search Range with a Preprogrammed Range Storing a Frequency While Searching for a Specified ChannelFunc then Tune Manually Changing a Search Range Scanning the Channels Turning Channel-Storage Banks Off and On Manually Tuning a Frequency Listening to the Weather Band Deleting Frequencies from ChannelsListening to a Weather Channel Displaying Weather Messages Using the Delay Function Special Features Locking Out Channels Locking OUT Channels or FrequenciesReviewing the Lock-Out Channels Locking Out Frequencies Clearing a Locked-Out Frequency Reviewing Locked-Out FrequenciesClearing All Lock Out Frequencies in a Search Bank Locked-out Priority Special Features Changing the Frequency Step Changing the Receive ModeDisplay Description Range MHz Search Step kHz Using the Attenuator Using the Keylock Using the Display BacklightTurning the KEY Tone on and OFF Changing the Display Contrast Cloning the Programmed Data from Scanner to Scanner Trunking Operation Understanding Trunking Programming Trunking Frequencies Setting Squelch for the Trunking Mode Programming Motorola Trunking Systems UHF-Lo Offset Frequency Size Code Programming Fleet Maps Talk Group IDS Talk Group ID Hold Storing Talk Group IDs Reviewing Locked-Out Talk Group IDs Locking Out Talk Group IDsClearing Talk Group IDs Clearing All Talk Group IDs in One Bank Open and Closed Modes Closed Mode Mode Open Closed Changing the Open/Closed ModeGeneral Guide to Scanning US Weather Frequencies Guide to FrequenciesHam Radio Frequencies Birdie Frequencies General Guide to Scanning Typical Band Usage Guide to the Action BandsPrimary Usage VHF Band Band Allocation Abbreviations Services VHF Low Band- 29-50 MHz in 5 kHz steps Meter Amateur BandMeter Amateur Band- 50-54 MHz Aircraft Band- 108-137 MHz Cm Amateur Band 420-450 MHz Government Band 406-420 MHzLow Band 450-470 MHz Frequency Conversion Problem Possible Cause Remedy TroubleshootingSquelch is not Resetting the Scanner RESETTING/INITIALIZING the ScannerDC 9V jack Care ResetInitializing the Scanner UHF T Specifications 9V DC Specifications71 Limited One-Year Warranty