Publishing Venue
Motorola
Related People
Authors:
Herbert Wolf
•
Daniel McDonald
•
Bill Felderman
Abstract
In today's existing Tnmking Communication Sys- tem, it is possible to assign a voice channel that was receiving interference from a previous call. Interfer- ence on a Trunking System can be received from many sources including neighboring Trunking Sys- tems, Conventional channels, harmonic transmissions from other transmitters, IF desensitization, and distant Trunking Systems when atmospheric conditions cause "RF ducting".
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MOTOROLA INC. Technical Developments Volume 13 July 1991
AVOIDING THE ASSIGNMENT OF CHANNELS WITH INTERFERENCE
by Herbert Wolf, Daniel McDonald and Bill Felderman
In today's existing Tnmking Communication Sys- tem, it is possible to assign a voice channel that was receiving interference from a previous call. Interfer- ence on a Trunking System can be received from many sources including neighboring Trunking Sys- tems, Conventional channels, harmonic transmissions from other transmitters, IF desensitization, and distant Trunking Systems when atmospheric conditions cause "RF ducting".
The system can detect interference when the chan- nel is not assigned and the interference is present for some duration, but during the time when a Trunking System is heavily loaded, the system does not cur- rently keep track of channels that are receiving carrier without connect tone and as a result may never take the channel out of service.
Depending on the signal strength of the interference, and the signal strength of the transmitting radio, it may not be possible for the radio to capture the receiver. Typically a channel with this kind of problem will be removed from service until the interference has no longer been detected for about 10 seconds.
This problem can be avoided if the channel is re- evaluated at the end of the call. Under normal condi- tions, all channel traffic signals will have ceased just after the last radio unit has signaled it is no longer transmitting. Whe...
