Coy, it seems you are confusing technologies here. D-Star repeaters and the analog repeater systems you are accustomed to are all FM and all conventional. D-Star is a digital audio format, that's all. It still operates on an FM carrier. What I think you mean to say is that the D-Star repeaters do not pass an analog audio FM signal as well as a D-Star digital audio FM signal. I also wish they did this.
In the U.S. land/mobile industry that uses the P25 digital audio format this is known as "mixed mode" (a term Motorola coined). I agree that Icom missed the boat when they did not build this feature into the new D-Star repeater systems. Perhaps they were unable to overcome some technical barrier, I don't know and they won't say (neither Icom or Icom America). Also, as you pointed out, D-Star digital voice is a narrowband signal occupying only about 6Khz vs. the 25Khz or so that amateur repeaters have often required to date. It is difficult to do a comparison between a digital audio system like D-Star and a conventional analog system so what my friends and I have done instead is we programmed several channels in our D-Star radios with the same simplex frequency only one channel is set for "DV" (D-Star digital voice) and another is set for narrowband analog while a third is set for wideband analog. We have performed numerous point-to-point (simplex) comparisons under varying conditions (day, night, clear, rain, dry, humid, etc.) so that we could each hear the differences for ourselves. Under some conditions analog works just fine and certainly sounds more natural but under other conditions, especially long distance, the digital voice can make communication more readily possible by audio compression and virtually eliminating the path noise that we usually hear on a distant analog signal. I frequently use P25 conventional, D-Star, and analog equipment and while the D-Star format and its error correction abilities may not be the best it does a very good job and I hope more amateurs explore this digital voice format and, I hope more amateur equipment manufacturers offer D-Star capable gear. Soon I hope to try out the European TETRA digital format for more comparison and education. These are the voice modes of tomorrow so I think it's in my best interests to learn them today. 73, Gary Coy Hilton wrote: > This brings some questions to mind. none of the D-STAR repeaters that > I know of (ICOM) have the ability to do FM repeat, If the repeaters, > antennas and the rest of the equipment weren't the same or nearly the > same and coo-located how can the test be fair? Also the D-Star is > narrow band with respect to the standard Fm repeater. With digital > either it's there or it's not. > > Granted digital is a good way to go but it is way too pricy right now > for me to think of purchasing I'll stick with my FM machines for now. > > AC0Y > > --- In [email protected], "Ron Wright, Skywarn > Coodinator" <[EMAIL PROTECTED]> wrote: > > > > hi all, > > > > In the FILES section of this board is a Weak Sig D-Star demon by > > WB9WZB. Most impressive test. > > > > Can anyone give details of the test...was same rig with power levels > > and antennas used in the test??? > > > > 73, ron, n9ee/r
