[DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
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. I believe that an amaueur application would be welcomed that did a translation between NXDN and its unit ID and the DSTAR Callsign identification. 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. 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?) The protocol is FDMA not TDMA and is similar in structure to P25 (but not compatible) Worth thinking about! Eric Meth - ve3ei > (Technically you also pick up the Kenwood/Icom partnership of their > TDMA-based systems when you cross over from Amateur to Commercial... I > haven't seen any significant up-take of the Kenwood/Icom system(s) in > the Amateur world. But they do have a digital product pointed squarely > at the commercial folks, marketing-wise. I leave it out of the > comparisons, because I'm an Amateur and I'm not interested in making > anything about my radio hobby Commercial.)
Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
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 m
Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
The modulation scheme used has the advantage of using half the bandwidth of D-STAR and both Kenwood and Icom supply a range of VHF and UHF moniles, handhelds and repeaters. At a later date there may be some merit in changing the modulation we use for D-STAR to improve spectrum efficiency. The relevent ETSI standards for are TS 102 490 and TS 102 658 ETSI Standards available as free downloads http://www.southgatearc.org/news/february2009/etsi_standards.htm OFCOM Digital PMR446 Interface Requirement IR2009 http://www.ofcom.org.uk/radiocomms/ifi/tech/interface_req/IR2009.pdf ETSI PMR http://www.etsi.org/WebSite/Technologies/PrivateMobileRadio.aspx CMX7141 Digital PMR Processor http://www.spectre-online.co.uk/products/wireless/pmr/ chip/cmx7141_digital_pmr_processor 73 Trevor M5AKA
Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
On May 19, 2010, at 11:06 AM, Trevor . wrote: The modulation scheme used has the advantage of using half the bandwidth of D-STAR and both Kenwood and Icom supply a range of VHF and UHF moniles, handhelds and repeaters. At a later date there may be some merit in changing the modulation we use for D-STAR to improve spectrum efficiency. ,___ 4FSK is permitted under the D-STAR standard. http://www.jarl.com/d-star/shogen.pdf 1.1.2 (1) My question would be compatibility with the installed base. John D. Hays Amateur Radio Station K7VE PO Box 1223 Edmonds, WA 98020-1223 VOIP/SIP: j...@hays.org Phone: 206-801-0820 801-790-0950 Fax: 866-309-6077 Email: j...@hays.org
RE: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
Half the bandwidth of D-STAR? What bandwidths do you believe that each uses? I thought that they were actually the same at ~6.25 kHz. From: dstar_digital@yahoogroups.com [mailto:dstar_digi...@yahoogroups.com] On Behalf Of Trevor . Sent: Wednesday, May 19, 2010 2:06 PM To: dstar_digital@yahoogroups.com Subject: Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions) The modulation scheme used has the advantage of using half the bandwidth of D-STAR and both Kenwood and Icom supply a range of VHF and UHF moniles, handhelds and repeaters. At a later date there may be some merit in changing the modulation we use for D-STAR to improve spectrum efficiency. The relevent ETSI standards for are TS 102 490 and TS 102 658 ETSI Standards available as free downloads http://www.southgatearc.org/news/february2009/etsi_standards.htm OFCOM Digital PMR446 Interface Requirement IR2009 http://www.ofcom.org.uk/radiocomms/ifi/tech/interface_req/IR2009.pdf ETSI PMR http://www.etsi.org/WebSite/Technologies/PrivateMobileRadio.aspx CMX7141 Digital PMR Processor http://www.spectre-online.co.uk/products/wireless/pmr/ chip/cmx7141_digital_pmr_processor 73 Trevor M5AKA
RE: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
--- On Wed, 19/5/10, Woodrick, Ed wrote: > Half the bandwidth of D-STAR? What bandwidths do you believe > that each uses? > I thought that they were actually the same at ~6.25 kHz. D-STAR GMSK is essentially a 12.5 kHz channel spacing system. http://utahvhfs.org/dstar_channel_spacing.html 4-FSK would permit 6.25 kHz channel spacing, twice the channels. http://www.npstc.org/meetings/20080618_NXDN_R%20Grimm.pdf Page 27 shows the FCC designated emission mask requirements for 6.25 kHz channels. 73 Trevor M5AKA
Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
The FCC defines bandwidth differently for Amateur vs Commercial - Amateur bandwidth is -26 db points either side of center in the US. Seems like LMR / PMR is -60 some odd either side of center. When I looked at the mask it seems like reality for DSTAR was around 12 1/2 khz occupied bandwidth @ - 60 points - about the same as narrowband (12 1/2 khz) LMR. JA1OGS - I have connected external GPS to an ID-800 - I remember having to set the GPS to NMEA output and seems like 4800 baud - there should be an older posting on this list - search messages. 73, steve On 5/19/10, Woodrick, Ed wrote: > Half the bandwidth of D-STAR? What bandwidths do you believe that each uses? > I thought that they were actually the same at ~6.25 kHz. > NU5D - Nickel Under Five Dollars
Re: [DSTAR_DIGITAL] Icom/Kenwood Digital Protocol was(RE: Honest Questions)
On 5/19/2010 3:29 PM, Steve Bosshard (NU5D) wrote: > The FCC defines bandwidth differently for Amateur vs Commercial - > Amateur bandwidth is -26 db points either side of center in the US. > Seems like LMR / PMR is -60 some odd either side of center. When I > looked at the mask it seems like reality for DSTAR was around 12 1/2 > khz occupied bandwidth @ - 60 points - about the same as narrowband > (12 1/2 khz) LMR. Gold star! You got it! (They're virtually the same.) For the computer/data geeks in the crowd, one can do the math from the CODECs and figure this out real easy too... voice still takes a specific amount of bandwidth -- albeit compressed heavily by a single manufacturer's chipset, because no one else competes in that market -- and that'll always equate to the same on-air RF bandwidth... CODECs are King. Modulation is just how you get that bitstream from "here" to "there" nowadays. If you see any product that doesn't announce the use of a new CODEC to compress down good old Nyquist's theoretical minimum bandwidth for A-to-D sampling rates to something smaller/compressed... you don't even need to read the rest of the Marketing "slick". It's the same as everyone else. Similar thing happens in "my" industry. Everyone claims to have a better way to skin the videoconferencing cat, but we're all using the same DSP chipsets, and they can do exactly the same things... Or, at the end of the day, only those who invest in mathematicians to write new algorythms and CODECs, gets to really say they've changed anything... then you release them to the standards committees... they get reverse-engineered, and the game begins again... Nate WY0X
