Hi Ron, I have been setting up D-STAR 23cm DD access points for the Marine Corps Marathon for three years now with other hams using their ID-1s at a dozen or so aid station and command locations. Works great to distribute tcp/ip access to the sports database via the ID-1s to remote computers using chat, browsers, and email. Crashes when some forgets to turn off automatic updates for their computer. Latency also tends to crash chat more than we are used to seeing. You should not operate two access points on the same frequency if they can see each other.
D-STAR Digital Data (Icom calls it DD) is not like AX.25 packet. It is not packet radio in the sense that we use AX.25 packet radios and nodes. It is a mode for transporting tcp/ip using ethernet over radio in a 128kbps raw channel between a user and an access point or other user. The DD Repeater is actually a one to many access point so that many ID-1s can connect to network services via one access point. It is not a packet node. Multiple ID-1 pairs can work as Ethernet bridges on the same frequency sharing the single 128kbps channel but effective bandwidth goes down. You are better off putting different pairs on different frequencies. Since there is no collision detection like on a wired Ethernet you just start getting bit errors, retransmissions, and delays when you have too much traffic. But works great as a long range bridge. The DD mode as well as the DV mode are described in the protocol definition that Icom, the ARRL and others have on their web sites. I do not think that packet type operations is a good match for D-STAR. But there are several nifty data applications (D*Chat and D-RATS). If you are using the slow speed data/voice mode called "DV" then you are chewing up a 4800 bps channel to try to get about 900 bps data across. Better to just set up a 1200 bps AX.25 packet channel. Or a 9600 bps AX.25 packet channel. In fact for the Marine Corps Marathon we set up a 9600bps access point and run packet in parallel. Depending on how well you type versus how well you mouse one or the other works better. In addition we run our 9600 bps packet on 2m so with the D-STAR DD up on 23cm there is considerable propagation difference as well. We are required to provide redundant data paths so this is our solution. Works great. I would say pick you solution based on what you are trying to accomplish. If you are just loading messages into a BBS use packet. If you have users trying to use WebEOC then use the 23cm D-STAR DD mode (but make sure they do not try to pull up the page with the huge map with all the nice detail.). And so on. There has been some reports of being able mesh network a set of ID-1s but have not tested it myself. Also, D-STAR is an acronym (silly one but means Digital Smart Technology for Amateur Radio) so I do not shorten it as "DS" but say D-STAR or D*. Sorry for being picky. 73, Tom Azlin n4zpt Ron Wright wrote: > Tom & Scott, > > I am still learning about DS and wanting to take advantage of the > digital modes. I know my question will show I know little, hi. > > I am interested in the Packet type operation of DS. That is a system > that uses a simplex one freq mode for passing info as the old analog > Packet system. Mostly used here for APRS and wx stns, but still some > comm. > > Is DD mode this, but using DStar? If so are packet modems used or is > another true non-tone digital like DS digital used? > > 73, ron, n9ee/r > > > > > > > --- In [email protected], "Tom Azlin, N4ZPT" <n4...@...> > wrote: >> Hi Scott. >> > > > ------------------------------------ > > Please TRIM your replies or set your email program not to include the > original message in reply unless needed for clarity. ThanksYahoo! > Groups Links > > > >
