NXDN™ specification released

[KY5U]

Like some of the comments I to believe it is time to figure out what actually works best,is widely deployable, can be used on HF, VHF, UHF alike. A good sauce to make a comparison is simple easy to remember readily available and recognizable to the user/consumer. these are the things that matter most.

Required bandwidth must be considered also. You will be one of many users of the spectrum.

[KB1RXA]

GMSK works for about $300 - no ICOM gear required. $300 covers HF/VHF/UHF with
a single analogue radio. No intermediating hardware required for freq. or time division. Radio to radio. Clear audio synced and/or data.

[K8WHB]

Be careful who you call "ignorant" - my background is in RF & computer systems engineering going back over 40 years.

I'm sorry if I just slew your sacred cow, but D-Star is like DSB AM in the 60s - yeh, it works, but it ISN'T the future.

I'll admit that both Yaesu and the NXDN folks may have an axe to grind in some of their conclusions, but their engineering analysis of the faults & limitations of D-Star are right on the mark.

None of the existing digital voice/data formats are ideal - if one of them was, everyone would embrace it and we could shut down all the research labs. Too much of what is deployed now days in the commercial area is deployed due to political or nationalistic reasons, combined with marketing muscle and crony capitalistic inside dealing (yes, I "DID" say Motorola) and NOT with technical merit. Unfortunately, hams have to deal with such sideshows if we want to piggyback on some of the "economies of scale" in manufacturing the hardware required to deploy digital systems. As time goes on and DSP hardware and other programmable components become more powerful & less expensive some of these constraints may well ease.

I stand by my statement regarding D-Star: yes, for amateur use presently it is by far the most widely deployed digital system, but so was DSB AM in the mid-50s. Just like DSB AM, D-Star won't disappear anytime soon, but I truly believe it will be but a "bit player" (no pun intended) in the future of amateur digital systems.

73,
Bill K8WHB

"D-Star is a dead end for a number of reasons that are well covered in the literature from Yaesu and the NXDN folks, so for the future of digital ham radio I don't even consider it".

I love ignorance ...

[KD4MOJ]

At this point ALL the commercial digital systems (as well as D-Star) are encumbered by patented codecs, and some of the licensing fees are nothing short of extortion (why do you think D-Star radios cost so damn much - the patent fees Icom has to pay are a good chunk of the premium). Developing an open source patent/royality free codec system for amateur digital that works as well as the AMBE+ codec and can be transmitted using C4FM has to be "Job #1".

The chip is $20. Buy the chip and build a radio or dongle/dvap etc.

Yaesu's new digital system

I wouldn't consider one portable a "system". Maybe they have plans for a repeater, maybe not, but they have a LONG road ahead of them since they are on their digital format.

...DOUG
KD4MOJ

[WA6ITF]

Just like DSB AM, D-Star won't disappear anytime soon, but I truly believe it will be but a "bit player" (no pun intended) in the future of amateur digital systems.

73,
Bill K8WHB

If there really is a digital audio future for ham radio anytime in the foreseeable future??? My suspicion is those attracted to digital on VHF/UHF have already made the move and on HF its likely decades away. And it will remain that way until there is developed and accepted a single digital standard that all hams embrace for all bands from DC to light. According to the ham industry, 2 meter FM HT's are still the biggest selling product in the marketplace and thats not going to change until there are like-priced digital radios to a single universally accepted standard. And I'm not holding my breath for that to happen soon -- unless it is government mandated -- which is not likely.

[VA7DGP]

Reminds me of the DVD Blu Ray Battles a few years ago. May the bet mode win.

73

Don
va7dgp

Too many digital modes! We'll have to see how they fight in the ring. Meanwhile I feel like the linux community/hackerspace is hard at work making a truly open radio standard.

NXDN is already in use by Icom (IDAS) and Kenwood (NEXEDGE). It is very much patent encumbered, and will probably remain a protocol for land mobile and professional systems.

EDIT:
Hurray it's on the way! http://codec2.org/. Not quite hackerspace, but definately open source. Currently Codec2 is great for HF, and takes up 1.1 KHz using FDMDV

Frequency Division Multiplexed Digital Voice

). The audio can be sent through FM on VHF/UHF but they're working on implementing it on a C4FM or GMSK modem to allow others to build radios that use it.

A worthwhile watch: http://www.youtube.com/watch?v=KsywWf8dQgU.

[AD7N]

Reminds me of the DVD Blu Ray Battles a few years ago. May the bet mode win.

73

Don
va7dgp

I know where my bets lie

VHF/UHF now have several Digital Voice modes duking it out, and HF is largely open. I think Codec2+FDMDV modem will become the most widely used digital voice standard on HF, simply because it's got a shorter feedback loop from user to developer (who's a ham to boot). Shorter feedback loop means faster turnaround on bug fixes and feature requests.

Not to mention...

it's totally free and software only. It can scale exponentially with just a download. No chip to buy, no "enter credit card here". Hams love free.

[W7QO]

I just have to dive in this abyss ..

I have 2 NXDN repeaters up and functional today with 2 more in the works. Let's be clear about some things.

a) there is no patent costs or should I say royalty costs. The cost of the codec from DVSI is down to the low double digits if not single digits in volume, so while you can call that a patent cost, it's really not much in the grand scheme of things (cost of all the parts of a radio).
b) there is simple no comparison between NXDN and D-Star. Icom did *everything* wrong with D-Star (not their problem they didn't know better just jumped on the JARL spec). And yet they did most everything right with NXDN (probably thanks to the joint development with Kenwood). D-Star suffers from 3 major issues. A religious group called the USTRUST that seems to thing they can *control* the network and callsign routing, the later is what turns most off after the initial "Oh gee, this is cool" factor is gone. Lastly, why on earth didn't Icom implement the FEC that could have been done to resolve this R2D2 issue... instead they elected to use the bandwidth to do low speed data, and yet that's really only available on the upper frequency implementations.

NXDN on the other hand, has NO callsign routing, is fully IP enabled from the factory, supports FEC so no more R2D2, and probably the best part the price. Repeaters are as easy as putting up an IC-FR5000/6000 (or if you want to save about $500, just get an UR-FR5000/6000, that's all that in the 19" rack chassis anyway. They can be had for around $700 complete with controller... Just add duplexer and PS and you are on the air with NXDN. The mobile radios from at least Icom are way cheaper than than a D-Star mobile, the HT's are a little more money, and I honestly don't know why they are that much higher.

To add IP linking, you simply get the UC-FR5000 linux board and plug it in, you'll need a $40 compact flash from Icom with some software on it, but that's it. Poof, you can link 16 repeaters together. I have mine linked currently to FLA and OH with TX and Seattle working to come online.

The repeaters as just brain dead easy to get on the air and quite flexible. You can support *both* 25kzh wide/5khz deviation FM or 6.25khz digital on the same box in either mixed digital or mixed analog modes. This allows for easy transition among any user base

The largest advantage for me is the 20-30% extension in coverage area with digital. For a weak signal on analog, with lots of background noise, that same signal is perfect in digital. The one thing you will notice is that you are either in the repeater or you aren't, there is no gray area .

If in Atlanta, 443.025+ PL 127.3/RAN 1 or 442.025+ PL 127.3/RAN 1 are both on the air. What we in the ham NXDN side are working on now is a more robust IP linked network... Thanks to the NXDN forum for releasing the specs, while it documents all the CAI, it also has allowed us to discover some things in the IP side.

If you think D-star is good, you have got to hear NXDN, it's simply amazing to hear Tampa or Cleveland exactly as if there were next to you on simplex...

And out of the box, there is interoperability with other NXDN devices....

If you have any questions, feel free to contact me directly... but I read through this thread and felt compelled to correct some miss-truths, specifically around the cost of the codec, etc. Would it be nice if it were free, or open hardware, sure, but it also has some advantages at being built by a commercial company and put in silicon, and that isn't cheap to do...

Alan - W7QO
Atlanta

[KE7VZW]

we don't want your halfway chips and specs without code; we want FULL SOURCE CODE. GO CODEC2!!!!!!!

Rick Muething has already showed how to force a paradigm shift with WINMOR in the Winlink system. I'm not sure that the source is released yet, but it's FREE, and Pactor III and above cost thousands of dollars per modem.

Free good, Source better, Free + source best.

Proprietary = doomed to fail