Trunking PTT Latency Part 2

March 11, 2007

The local trunked UHF radio system causing interference wanted to talk about more than just interference–they have a problem with radios randomly failing to transmit. Monitoring for LTR trunked radio system overloading: in a modern digital trunking radio system, many statistics are available. For an LTR system, most controllers are not that sophisticated. What will happen in LTR is that if too many groups are homed on one repeater, the chance of two people keying up before the repeater can make its first response goes up. Then, either neither party can transmit if the overlap is early (no clear-to-talk), or both will transmit. In the first case, out-of-range tone is given. In the second case, clear to talk is given but the transmissions are uselessly garbled (or maybe, one signal dominates).

Solving LTR trunked radio system overloading involves reprogramming every radio in the system, so plan first. Distribute home channels for different groups that talk at the same time. If the system needs an “all call”, have a small dispatch console that can key multiple radios simultaneously–if not, you’ll need to implement one. This solution is fairly unique to LTR.