Randall WW5WR wrote: > You know I really must say what in the name of HAYDEES > was ICOM thinking when they opened this can O worms? > But to go DIGITAL and leave out MSG capabilities is > really really a waste of band width wouldn't you say? > I mean if you are putting so much info in such little > space why wasn't that part of the idea? Look at the open > possibilities that could be added if they had only left > room for that? Sure would have been nice to have one > mode that would have done it all huh? So it seems we > will still have to have our FM Voice radio, D-Star > Radio and APRS Radio if we want to be able to run all > modes. Plus an HF Rig of course. =D
Can O worms? The JARL designed a "open" standard for the transmission of information using digital technologies. ICOM has implemented that standard ... and in a few areas ... taken some liberty to extend / expand it. The stream of bits that comes out of a D-STAR DV radio contains mostly the encoded voice (audio) information ... and a little more information transmitted in parallel, so to say, with the voice information. So at that level of implementation - D-STAR could be thought of more like another modulation scheme: AM, FM, D-STAR (This is not totally accurate but I am trying to find a way to convey what's going on - again I suggest at least a simple look at ICOM or JARL marketing brochures and maybe one of the PowerPoint slide decks from any one of the numerous D-STAR presentations.) In that DV digital data stream includes some "fields", which among other things include your call, a destination call (often just programmed as CQCQCQ), and a couple of "repeater" callsigns (used when you are using repeaters and possibly Internet gateways). That is really all the standard provided for ... it is the foundation to build other things on top of. This is not much different than: - APRS information is encoded in AX25 packets - AX25 is typically encoded into FM transmissions using a TNC - an FM transceiver is involved There is nothing stopping anyone from building a PIC based application like the TinyTracker (or similar devices), HamHUD, etc. and connecting that to a D-STAR radio. You could essentially build a similar system on the D-STAR architecture. So ... your comment: "But to go DIGITAL and leave out MSG capabilities is really really a waste of band width wouldn't you say?" Absolutely not. My perception is that your view of a D-STAR radio should be more like a cell/mobile type device? If so ... what you are looking for then is a radio that in addition to supporting digital communications (TX/RX from the RF level) you want a bunch of applications to be built into the radio as well? What are you willing to pay for it? (Consider that the cell/mobile devices are "cheap" as compared to amateur radio equipment largely because they are manufactured in large quantities for the masses which helps offset the development and manufacturing costs.) A good example of a waste of bandwidth is a lot of 1200 baud 2m packet transmitters beaconing excessive information that in turn is picked up and relayed by a lot of digipeaters ... one of the biggest problems IMO with the packet network is the lack of network design and consistency of parameters in use by users of the network. I used to have a HamHUD in the car and some friends have trackers; our local group that I'm the president of has a wide area APRS digi ... >> ... will still have to have our FM Voice radio, >> D-Star Radio and APRS Radio ... I'm not aware of any APRS radio (correct me if I am wrong). As I noted above - to do much of the APRS things you need either a computer program or a PIC based device (that implements basic APRS functionality) ... PLUS a TNC and radio. When I had the HamHUD II in my car I had the Alinco 2m radio with the built-in TNC -- that had to be dedicated to the HamHUD (APRS) device. > So can the D-Star dual band rig scan FM Repeaters > on the Sub Band and run D-Star on the Main band? I can speak to the functionality of the IC-2820. It has two VFO's - but I don't believe they are ever referred to main and sub bands. Both can receive analog transmissions simultaneously. If you add the UT-123 D-STAR module into the radio ... you can use D-STAR on *either* of the VFO's, but only one of the VFO's at a time. In other words - you can have: analog/analog d-star/analog analog/d-star but not: d-star/d-star (simultaneously) And that is because in this implementation there is only one D-STAR digital decoder. The same D-STAR module for the IC-2820 also includes GPS support ... with a small GPS antenna. I have my rig setup to transmit my position in the D-STAR transmissions. And suitably configured D-STAR repeater systems (using non-ICOM supplied software on the repeater gateway computer) can decode that GPS information and then submit it to the APRS network over the Internet. Therefore you can see my position reports as if they had come from an APRS device connected to a TNC to a 2m radio, etc. 73 Bob W1QA
