Bill, Though I have no personal experience with a trunked simulcast system, I did have a class from the engineer assigned to a large end to end system that the company that I work for takes care of. Among the other problems that may arise are frequency stability which the GPS should take care. All transmitters must be aligned and set with the same service monitor so all frequencies are as close as possible to being the same, as well as transmitter deviations and PL/DPL levels/frequencies (if used). One other problem with the overlap is controlling the overlapping coverage so it may not be too large an area, and/or adjusting for areas of prime coverage importance, by increasing or decreasing transmitter power output. The other problem to be addressed is line compensation for time delay so the audio arrives at all base stations at the same time. This step is to eliminate or decrease possible audio distortion due to arriving at a different time/phase. I am sure there may be other factors to consider as well. When set up right it appears to work well, when not there may be problems (customer related of course). I hope my brief explanation of what I know is a help.
Steve KB3FPN ----- Original Message ----- From: Bill Powell To: [email protected] Sent: Sunday, September 30, 2007 9:28 PM Subject: [Repeater-Builder] Overlapping Coverage I'm considering a trunked (type TBD) system on 470 that will have significant on-channel overlap. The overlap comes about due to the need for multiple sites to fill the many holes that will exist with a single site regaurdless of location or (reasonable) tower height. Assuming that ALL the transmitters are GPS locked and properly set up for simulcast operation, what operational problems might I expect? Thanks, Bill Powell
