Ron Wright wrote: > Have not done the math, but for 25 kHz spacing as on UHF what about > putting 2 > D* repeaters one + 6.25 and one -6.25 kHz from a standard channel.
You're starting to "think like" the folks who are trying to come up with good ideas, now you've got it! However... you forgot the next step... Next you have to think about the original adjacent channel analog systems on either side. It's a "matrix". Now mess around with the locations of all three. Trying to do a "raw" matrix analysis gets complex, real fast. > Might be necessary to seperate distance wise as we do for 2m 15 kHz > adjacent repeaters. Here it is 35 miles. We have to go a LOT further here, based on Height Above Average Terrain (HAAT). On VHF we have some systems that will EASILY hear a mobile user out past 80 miles. (And this is why each area has their own coordination bodies... tailoring the situation to the local conditions, is key.) > The D* rigs can do this and might be enough seperation. However, I do > not know the D* rcvr selective spec. They might use the same IF filters > that is used for the analog. Needs more bench testing and real-world experiences with digital "against" digital and digital "against" analog. I suspect we'll see more good work out of people who've already published. (Utah's coordination group, and Mark N5RFX have both done some very nice published work for D-STAR systems specifically, and I've talked to a number of radio folks who DID similar or useful work to test such things on their systems, but never had time or energy to publish.) Nate WY0X
