Anyone who buys a D*Star radio thinking that it can send and receive bi-directionally concurrently should go back and take a look at some basic radio theory. On these radios, when the transmitter is up, the receiver is shut down. Add to that the fact that there is only a single AMBE chip onboard, and you can easily see that you're limited.
However, if one uses a little bit of brain power, and learn what the technology capabilities are before buying, one shouldn't be disappointed. There are limitations with every radio technology out there, no one has figured out how to bend the laws of physics yet. That's why amatuers can provide backup communications to the other commercial users. Amatuers should not only have a larger selection of radio modes and bands available to them, but also a better understanding of the physics involved, and through that, radio propagation characteristics. You can argue till you're blue in the face, but you're not going to change the laws of physics, nor the capabilities of the current batch of radios. However, those that understand both of these concepts and are willing to work within those constraints will eventually leverage all they can out of the gear, and be able to do interesting things with it. Those who don't have the gear, and only point out the limitations won't be the ones making interesting things happen. As with all of the amateur world, there are always different avenues for people to follow, and there's no one forcing anyone to operate in a mode or band that they don't want to operate in. Everyone can play where they want, and with the toys they want. James VE6SRV On 7/12/09, Daron Wilson <[email protected]> wrote: > >>No problem to send sub channel text files or text (dchat/d-rats etc) >>simultaneously during voice transmission if you include that as slow >>speed data (I do). >>Just any file transfer or that requiring target feedback error >>correction will be corrupted during simultaneous voice transmission. > > Exactly. The marketing folks say you can do simultaneous voice and data, > which technically on one data stream, you can. The field folks interpret > that to mean they can carry one a conversation with anyone in voice while at > the same time, seamlessly sending data hither and yon. The reality is that > it doesn't work that way. What I'm seeing happen is users bought the radio > thinking that they could do the former, tried to do things with it and > discovered the inherit limitations, and we're already seeing folks > frustrated and selling the gear because it doesn't really do what it > 'sounded like' it would do. The laws of physics still apply to Dstar. > There is only one RF path via the repeater, and while that path > simultaneously supports voice and data packets, it is not as versatile as > two independent systems (i.e. two RF paths vs. one). Only one user at a > time can transmit simultaneous voice and data, the other users must wait > their turn. If I'm transferring a data file to someone, having a third > party jump in on voice trashes my transfer. > > 73 Daron N7HQR > > > > > > ------------------------------------ > > Please TRIM your replies or set your email program not to include the > original message in reply unless needed for clarity. ThanksYahoo! Groups > Links > > > >
