The channels shown are approximately 50% loaded, which means that they are occupied by a carrier 50% of the time.The dark areas in the top 5 lines indicate when the repeater is in use, and the dark areas in the bottom line indicate when all five channels are busy.It can be seen from this chart that if the channels are not trunked and only one channel is available to the user (as with a community repeater), there is a much lower chance of obtaining a channel at any instant.
Figure 2 shows that for a given percentage of airtime loading, blocking probabilities are reduced as the number of trunked repeaters increases.
Advantages of trunking include less waiting to access the system and increased channel capacity for a given quality of service.
Since the probability of all channels being busy at the same instant is low (especially in larger systems), the chance of being blocked is much less than when only one channel can be accessed.
7.1 SELECTABLE SYSTEMS AND GROUPS 7.2 RECEIVE PRIORITY ID CODES 7.3 RIC REPEATER INTERCONNECT ID CODES 7.4 SYSTEM SCAN 7.5 GROUP SCAN 7.6 PROCEED (CLEAR-TO-TALK) TONE 7.7 TRANSMIT INHIBIT 7.8 FREE SYSTEM RINGBACK 7.9 BUSY QUEUING 7.10 SYSTEM SEARCH 7.11 TRANSPOND 7.12 CALL INDICATOR 7.13 HORN ALERT 7.14 TIME-OUT TIMERLTR radio systems utilize a control concept called trunking.
As it applies to radio, trunking is the automatic sharing of channels in a multiple repeater system.
A repeater is held for only the duration of the transmission with dispatch calls.