NXDN specification released to the public

[KR4BD]

I just saw this on QRZ.com (a ham radio website). This should be good news for the scanning hobby.

NXDN™ specification released

The technical specification for NXDN™, a FDMA digital voice technology supported by ICOM and Kenwood, is being opened to the public domain.

For the past 5 years both ICOM and Kenwood have been producing VHF/UHF mobiles, handhelds and repeaters to the NXDN™ standard. The equipment has a transmitted bandwidth of 4.0 kHz and is typically used in 6.25 kHz channel spacing systems.

The specification is currently available in response to an email request but the NXDN™ Forum indicates it will be available for direct download later in the year.

NXDN™ Forum To Open Technical Standards

 

[KF0SKV]

That is good news, especially for the railfans, which it appears railroads are leaning towards NXDN Technology for two way communications in the future.

I have heard some Public Safety entities have shown interest in NXDN as well.

 

[SCPD]

There are a few public safety agencies already on the air with it. Depending how much it will cost the scanner makers we may or may not see a scanner that will do NXDN.

 

[fourthhorseman]

My question is,,,NXDN being,to a degree an FDMA technology,,is this something the newer receivers
(psr800) can be updated via firmware/dsp updates?....fingers crossed....my ol-lady wont be smiling at Another
radio crackling away in my den...lol...

 

[JStemann]

There are a few public safety agencies already on the air with it. Depending how much it will cost the scanner makers we may or may not see a scanner that will do NXDN.

If I remember correctly, there are several public safety agencies in kentucky using it. The only "problem" for the scanner listeners is (i think) all the nxdn radios come with basic encryption installed, standard. So, if that is the case, it'd be pretty simple for an agency to go silent (or garbled), when/if the scanners start rolling out.

Jeff.

 

[SCPD]

If I remember correctly, there are several public safety agencies in kentucky using it. The only "problem" for the scanner listeners is (i think) all the nxdn radios come with basic encryption installed, standard. So, if that is the case, it'd be pretty simple for an agency to go silent (or garbled), when/if the scanners start rolling out.

Jeff.

That's a good point about the encryption. If it's already there and very easy to turn on you can bet agencies would love to use it.

 

[balibago]

Basic NXDN scrambling

I guess the next thing we need is a NXDN descrambler. The way it's going you are going to need 50,000 dollars to set up a monitoring post.

 

[balibago]

You know what would be good too. A program to turn Spanish voice into English in real time.

 

[sirsmiley]

Its the same as MOTOTrbo isnt it? Well similar anyways....Trbo can be picked up by some scanners/devices but since there is no cost involved people just turn on the built in encryption which makes it essentially useless to have a trbo scanner anyways. Nexedge will be the same..why not use encryption when it comes built in for free?

 

[baycomm]

The primary issue is not the ability to receive NXDN (or TRBO) but that both use the same voice compression CODEC from DVSI. They are in business to sell this technology. Any commercial product that can recover voice from NXDN or TRBO would require the payment of royalties to them.

 

[burner50]

If I remember correctly, there are several public safety agencies in kentucky using it. The only "problem" for the scanner listeners is (i think) all the nxdn radios come with basic encryption installed, standard. So, if that is the case, it'd be pretty simple for an agency to go silent (or garbled), when/if the scanners start rolling out.

Jeff.

All of my NXDN gear supports basic encryption (16 bit)...

But most Kenwood radios recently supported some sort of scrambling out of the box... how many of your local agencies sound like Donald duck?

 

[canav844]

I guess the next thing we need is a NXDN descrambler. The way it's going you are going to need 50,000 dollars to set up a monitoring post.

Or just a $10 yard sale scanner, a lightly used laptop and DSD
Digital Voice Decoding Software - The RadioReference.com Forums

While many of these offer encryption included, most people at least around me are under the impression if they're digital they're encrypted, and even for the time being they can see that the scanner doesn't pick them up. To make it portable takes a little more work but the beauty of the growth of streaming is that there's the ability to get it to a smartphone.

My hope with the NXDN format being published like this is that it will help a few others start making it, and drive the cost down, and perhaps even lead to it being added in some of the Wuoxon and Baufeng (I'm sure the spelling is off) type radios to help some of the digital modes spread on the amateur bands, as well as the business bands. Texting, APRS (there's software to make the transition now and yes APRS will do texting as well) and voice all on the same frequency, could theoretically simplify things for some applications. It may also lead some amateurs to come across it and develop things similar to the DVAP or the Dongles out there for DSTAR (which this is simpler but already more cost effective on the repeater side, and near pennies compared to a Quantar) or develop means to convert analog repeaters to be able to do mixed analog and NXDN

 

[mmckenna]

NXDN uses the AMBE+2 vocoder, same as MotoTrbo and P25, so the hardware is there in the scanners that support P25, to an extent. Most Kenwood NXDN(NexEdge) radios could be reflashed to support P25, however they will do either NXDN or P25, not both. I think adding NXDN to scanners is only a short time off. Where there will likely be an issue is with the trunking protocols, the trunking protocols used by Kenwood and Icom are not compatible. Also, Kenwood NexEdge radios can run 4KHz bandwidth in a 6.25 channels or 8KHz bandwidth in 12.5KHz channels. Icom only allows the 4KHz/6.25 option.

 

[kruser]

Or just a $10 yard sale scanner, a lightly used laptop and DSD
Digital Voice Decoding Software - The RadioReference.com Forums

the Dongles out there for DSTAR (which this is simpler but already more cost effective on the repeater side, and near pennies compared to a Quantar) or develop means to convert analog repeaters to be able to do mixed analog and NXDN

Have any links for decent DSTAR Dongles? That sounds interesting.

Are there any software DSTAR decoders yet similar to DSD or some of the digital mode decoders such as Multipsk or fldigi?
NXDN capability in a software decoder package like fldigi or multipsk would be neat also.

 

[canav844]

Have any links for decent DSTAR Dongles? That sounds interesting.

Are there any software DSTAR decoders yet similar to DSD or some of the digital mode decoders such as Multipsk or fldigi?
NXDN capability in a software decoder package like fldigi or multipsk would be neat also.

I don't know of any software ones, (DSD Identifies components of the packets but doesn't decode the voice), this is the mainstream one in the US DV Dongle but where it starts to get cool is all the ground up efforts made by enthusiasts to develop solutions, if you take a read at KB9MWR's blog Advancing Ham Radio.. different ideas: DIY Compatible D-Star Repeater - Green Bay there is a wealth of information there, going through the years of posts, that lead to links that lead to more links and so on.

At which point I shall unthreead jack, but that's the kind of thing that I think would be neat to spread to NXDN, as it's clearly a fairly rapidly growing technology in the amateur world; and it's one of those things where as NXDN was originally designed for the business band, may be much more likely to see the engineering efforts of amateurs develop and improve technology used on the business and public safety bands (which I believe was also the case for some of the amateur TRBO pioneers a few years back). As making it easy for the little guy to access the information, will likely prompt more experimentation with the technology.

 

[kruser]

Thanks for the links. The dongle itself looks to be exactly what I was looking for.

The info at KB9MWR's blog also looks like some good reading!
I did not get the D-Star option with my last purchase as it was not very popular at the time but now there seems to be a fair amount of use in my area so It's worth looking into.

 

[plaws]

The primary issue is not the ability to receive NXDN (or TRBO) but that both use the same voice compression CODEC from DVSI. They are in business to sell this technology. Any commercial product that can recover voice from NXDN or TRBO would require the payment of royalties to them.

Or D-STAR - same monopoly chip. This is the same as the D-Star protocol being "open". It is, but the codec used to digitize the voice is still proprietary to a single vendor so you're still stuck paying a toll.

 

[voxiso]

Just about every county in Kentucky is going to NXDN.. My area is damn near silent already.

 

[JStemann]

Just about every county in Kentucky is going to NXDN.. My area is damn near silent already.

Yep, I don't know why exactly, but I have noticed a lot of KY (county agencies) really seem to be heading to NXDN. Maybe I just noticed it more because I'm close to KY, but they seem to be picking it up more than most other states.

I understand it being a cheaper alternative to moto or harris, just kinda surprised by how many agencies in KY seem to be going that route.

Jeff.

 

[902]

I went through the posts and don't recall seeing another factor between NXDN and Mototrbo. NXDN is an FDMA technology - it's something like P25 except the rate is slower and it conforms into either an 8K3 or 4K0 channelspace depending on the configuration. Mototrbo is actually ETSI's DMR standard. This is a 2-slot TDMA technology, where the radios have to sync up to get a channel slot. The NXDN system achieves 6.25 equivalency as a stand-alone device. The DMR achieves it by having two slots out of a legacy "narrowband" channel. DMR "looks a lot like" P25 Phase 2.

That standard is out there, too. A scanner manufacturer could potentially make a scanner for DMR and for NXDN that is additional firmware. But it has to give them some return on investment and it would probably not include any of the proprietary embellishments and adulterations of the standards.