On May 19, 2010, at 8:55 AM, ve3ei wrote: > > Nate and any others that are interested > Icom/Kenwood and others use NXDN (4 Level FSK/FDMA 6.25 kHz Technology) > see www.nxdn-forum.org. It is a relatively open digital standard for > commercial equipment for its Over the Air (OTA) communcation protocol.
Ah, yes... NXDN was what I was referring to... and I thought it was TDMA. Thanks for the correction that it's FDMA. > > I believe that an amaueur application would be welcomed that did a > translation between NXDN and its unit ID and the DSTAR Callsign > identification. Whoa, back up a bit there... if you have access to the data streams from both an NXDN and a D-STAR repeater in a standard way... you know, a published API and/or protocol... "converting" between the two is a relatively easy programming chore for a "mere mortal" level programmer. D-STAR has no published API, unless you count feeding things in/out through D-PLUS. Out of the box from Icom though, there's certainly no documented way to push/pull audio streams from a D-STAR Gateway to anything else. I'm going to assume, but don't know, that Icom and Kenwood aren't publishing an API to talk to whatever handles Internet connectivity on the NXDN boxes either, but maybe they have to stay competitive with the API integration that Moto allows developers on the Batwing TDMA system (TRBO). > There are a certain group of amayeur radio operators who like to use > commercial equipment on the amateur bands (They have an M branded on the back > of their heads). I agree that sometimes, in certain situations such as > intermod and spurious emissions, that it would make sense to use commercial > equipment. I like using commercial gear that's OLD because the quality level never went down, but people are afraid of "figuring out" commercial gear, and you get them for pennies on the dollar. Example... my "fleet" of GE MP/A HT's on various bands for analog use. Not one of them purchased for more than $80, and yet they outperform any possible Amateur gear I could have bought with the same money. > Myself and one other radio amateur are looking into that possibility. Several > amateur groups are looking to replace their 25 year + Micors or MastrII > repeaters that are getting long in the tooth. The new Icom series FR5000 > (VHF) or FR6000 (UHF) commercial repeaters do both Analog and Digital on the > same frequency "on-the-fly", are small (2 rach units high) and you could have > a VHF and UHF repeater in the rame rack unit thereby freeing up to 2 racks > worth of equipment. (Think of how many computers you could install?) I'm not involved in it, but there's been a surge of MotoTRBO deployments here lately. I think half the State will soon be covered (probably this summer) and the uptake has been way faster than D-STAR which has been on the air for many years here. D-STAR's not growing as fast, but there is a new group putting up a South Denver Metro system. They're putting it in a completely closed site with no physical access where they'll have to call professional repeater maintainers that handle other gear at the site to even reboot it... I'm not sure if that'll work out well for them or not, given the number of times we've had to reboot W0CDS's controller to get things "back to normal". I'd say that we've done that at least annually. We'll see. They'd better buy gear to remotely reboot it, is all I can say. > The protocol is FDMA not TDMA and is similar in structure to P25 (but not > compatible) Yup, I'd read that and then lost it from the brain cells. > Worth thinking about! Definitely am, but the closed nature of the gateways/servers in all systems is the limiting factor for interoperability. Reverse engineering is time-consuming and dumb, if one can buy a working system with a published API. This and the "this acts more like radios I'm used to" is what's driving the up-take of TRBO around here... you program it once at the PC, and use channel numbers after that for linked, unlinked, whatever... no fiddling with callsigns. This seems to be a big draw. Especially for the crowd that wants to link locally, but really could care less if they can link to other countries. They don't want or need to talk to California, or Croatia (joke...), they want to reliably key up and link Statewide as a maximum "linking radius". A well-designed TRBO system can easily do that, as can a D-STAR... but they're seeing the TRBO as their "answer" to this right now. The ARES crowd here are far more appreciative of the user interface on TRBO right now, than the user interface on D-STAR. The other common comment is that the audio amp and speaker configuration are "done right" for the TRBO rigs, and the high output audio blows away all of the Icom D-STAR HT's. I hope for NXDN's sake that Icom put a bit more kick in the audio in their commercial HT's for that product line. (Remember, I'm just the messenger here, I'm not pushing EITHER system locally. I just run the D-STAR gateway. This is just a narrative of "what's going on".) NXDN is the answer to TRBO on the commercial side, but I don't see *easy* interfaces happening to D-STAR anytime soon, unless that's some super-duper developer's "hot button" and they want to spend oodles and oodles of time figuring it out. We'll see... -- Nate Duehr, WY0X n...@natetech.com facebook.com/denverpilot twitter.com/denverpilot
