Hi Peter, The D-Star is a JARL open protocol and was developed in Japan based on their desires for a digital mode. It falls far short of what I would ever want but there are those who are investing a lot of money in trying out these technologies.
The VHF/UHF rigs from ICOM are dual mode and can work with either digital or analog. The 1.2 GHz rig is strictly digital and operates at a much higher data rate and has a raw 128 Kbps speed. You are correct that if using the digital protocol, it is only going to be able to communicate with other D-Star units since it can only use the one protocol. If other protocols eventually develop, and based on the performance of D-Star, I would expect this to happen, newer equipment may be possible to be backward compatible. My hope is that eventually there might be some digital voice protocol that was compelling enough to consider "investing" in such a system, but it just does not seem to be there at this time. It might have been better if they had had input from other potential users around the world, but you have to give them credit for coming up with an open protocol. The main advantage to using D-Star is the much narrower bandwidth. While this is not really much of a concern here in the U.S., perhaps it is in other parts of the world. From the audio quality comparisons that I have heard, the disadvantage seems to be the much narrower bandwidth:( The audio quality is very poor compared to analog. Some say it is a necessary tradeoff and since cellphones have low quality audio, people will accept it. Maybe this will be true for new hams? But most of the time we are talking to other stations who are full quieting or reasonably close, so any advantage from hearing a quiet signal (though of lower audio quality) is minimal in many cases. One of the main reasons for using FM modes on VHF and up is the voice quality and the practical use of repeaters. And we had the space on the higher bands, which we did not have on the lower ones. This may not have been such a problem if they had used the entire bandwidth for voice, but if I understand it correctly, they have a slow speed channel (~ 1 Kbps) that can be used for digital data. I don't think that this bandwidth can be used by the voice channel if the data channel is not being used, but if anyone knows for sure it would be good to have a definitive understanding. My view is that they may have had a better quality audio if they had used the entire bandwidth for voice when you consider that voice has very high throughput requirements to work well. 73, Rick, KV9U pcooke2002 wrote: >Am I correct in believing > >these digital transciever only talk to other digital transcievers. >They don't have a switch in there that allows them to talk to non- >digital trancievers. > >If not why doesnt some smart company put a switch in a radio that >allows ditial analog usage? > >Also DSTAR seems to be propriatary protocal. >does that mean a DSTAR radio can only talk to another DSTAR radio, or >can they talk to other digital vendor radio? > >Peter >KG6OUE > > > > >
