ICOM/Kenwood Consortium Has 6.25 kHz Digital AMBE++ Radio

[ASTROMODAT]

This is bizarre! The ICOM/Kenwood consortium is pursuing a 6.25 kHz AMBE++ digital radio utilizing 4-level FSK via FDMA. APCO P25 Phase II 6.25 kHz calls for the use of TDMA. What in the heck is ICOM thinking?! Great, come out with a 6.25 kHz radio that isn't compliant with APCO P25 Phase II. I suppose they may be (exclusively?) thinking of the ETSI market, and maybe they have (wisely) written off the US P25 Phase II market to the Big Gigantic Winner, Motorola. Guess one can't blame them for not wanting to pick a fight with someone who can definitely whip them in a heartbeat!

At least if they were SONY they'd have a fighting chance to change (or at least ever so slightly influence a wee bit) the P25 Phase II standard, but as that ol' fart told Dan Quail, "ICOM ain't no SONY!" (I'm paraphrasing, of course)

http://www.icomamerica.com/press/?id=20050406

[Wowbagger]

This is bizarre! The ICOM/Kenwood consortium is pursuing a 6.25 kHz AMBE++ digital radio utilizing 4-level FSK via FDMA. APCO P25 Phase II 6.25 kHz calls for the use of TDMA.

Not true. Phase 2 calls out 2 different protocols. The first is a 6.25 kHz CQPSK that is otherwise compatible with Phase 1 APCO (9600 bps, 4800 baud, no timeslotting, IMBE vocoder).

The second is a proposed 2 slot TDMA, 12.5 kHz channel bandwidth, with 9600 bits per second (4800 baud) using the AMBE vocoder to reduce the data rate per channel.

The reason they are not combining the CQPSK modulation with the AMBE vocoder and TDMA is that to do CQPSK your power amps have to be linear (class A or at least AB) rather than the class C amps used in FM.

[ASTROMODAT]

Does this mean that the ICOM/Kenwood approach (4-level FSK using FDMA) would be a potential fit for Phase II P25?

[tvsjr]

ICOM/Kenwood announced their digital development to offer digital voice to users that can't/don't want to afford P25. Looks to me like they're developing technology that waxes P25 Phase 1 and keeps up with P25 Phase 2, and they're aiming sub-$1K per radio.

P25 is all well and good, but the technology is lagging (IMBE sucks compared to AMBE), the spectral efficiency didn't increase (at least with Phase 1), and it's rather expensive.

The more stupid stuff that Motorola does (see selling their depot and sending the work to Mexico, charging $4K per portable radio, etc.), the more people are swearing them off and going to Icom/Kenwood gear (look at how many rather large departments are going Icom/Kenwood/Vertex that have been Motorola-only shops for 2+ decades). A better digital implementation would only provide one more draw away from Motorola.

I know, Larry, Motorola's got P25 in the bag, they can do no wrong, etc. The next few years are going to be rather entertaining... Motorola's already losing ground - will they fix it or will they slide off into the abyss?

[ASTROMODAT]

The more stupid stuff that Motorola does (see selling their depot and sending the work to Mexico...

Where is the post/info about Motorola selling their Repair Depot and sending the work to Mexico?

[tvsjr]

In the General forum. You mean you haven't read it? I figured we hadn't heard from you because your head exploded as a result.

In a nutshell, Elgin is being reformed and will be managed by CTDI. Mobile and portable service will go to El Paso, TX, for "management" or whatever, and will be sent to Guadalajara for the actual service work.

[mr.syntrx]

This is great news on Icom and Kenwood's part.

ALL two-way radio in Japan is going to be narrowband digital within a couple of years, due to a government mandate - in fact, quite a lot of Japanese commercial radio already is. I suspect that is the reason behind Icom and Kenwood's motivation to produce these products.

ETSI are working on an open digital standard. It is initially intended for the European FRS-like PMR446 service, but it has real potential for commercial radio, too. It'll be interesting to see how this pans out over the next few years.

Commercial users do not care if they're on the same page as the public safety community. Plumbers and dump truck drivers don't talk to the cops or fire over the radio. The excessive expense of Project 25 equipment can't be justified by the vast majority of the commercial 2-way radio user base.

[Wowbagger]

ALL two-way radio in Japan is going to be narrowband digital within a couple of years, due to a government mandate.

Ahhh - that explains this. I'd wondered what was the driving force behind D-Star, as (from a ham perspective) it really doesn't seem to me to give you that much of an advantage, and greatly increases complexity. But if amateur radio in Japan is ALSO being forced to narrowband digital, that would be the driving force.

I am a little disappointed in TAPR for picking AMBE as the core of a ham protocol - the whole idea behind amateur radio is that, at least in theory, a ham can build their own gear. You cannot build your own AMBE vocoder - you have to have a licensed vocoder from DVSI. (personal opinion here, not Aeroflex!) I'd have rather seen D-Star based upon something like speex, given that it is Free for all.(end personal opinion).

[mr.syntrx]

I actually meant all commercial land mobile radio, I don't know if amateur activity is in the same boat. The Japanese have a bit of a spectrum crisis - they have a huge population density, and of course, there's only so much spectrum to go around.

[ASTROMODAT]

ALL two-way radio in Japan is going to be narrowband digital within a couple of years, due to a government mandate.

Ahhh - that explains this. I'd wondered what was the driving force behind D-Star

Not true.

D-STAR was NOT driven by commercial radio users' interests. The JARRL drove the D-STAR standard, and the standard was designed exclusively for Ham radio use. The original driving force behind the JARRL's push for the D-STAR standard was for mobile HSD on the Ham band, and not specifically because of spectrum efficiency. Keep in mind that the D-STAR HSD standard calls for 130 kHz of spectrum per each data channel, a not too efficient use of spectrum! (Note: Motorola's VRM uses a scant 25 kHz of spectrum for 96 kb/s HSD, whereas Icom's D-STAR uses a gargantuous 130 kHz of spectrum for only 80 kb/s!). Heck, in Japan they can't even use repeaters on VHF, and most of their Ham activity is on simplex in Japan, with 1.2 GHz being their most popular repeater choice. It's MUCH different there than here in the States.

We also have a huge spectrum shortage problem in the US that is worse than Japan's spectrum situation. Don't forget the US also has a mandated requirement for federal radio users to increase their spectrum efficiency, with a date certain, etc.

There may be spin offs and carry overs from D-STAR to commercial interests, such as the fact that Icom now has some experience with the AMBE vocoder, etc. On the other hand, Icom already has P25 radios, so I don't know if there is much of a relationship, even in the most general technical sense, between D-STAR and commercial digital radio development.

BTW, so far to date, D-STAR has been a dissasterous flop, as equipment is not selling. This may (or may not) change once Icom releases the VHF and UHF D-STAR repeaters (which have no HSD capability). Only time will tell, but so far, the commercial success of D-STAR looks bleak, at best. And that's too bad...

[MTS2000des]

D-Star is not designed to compete with P25. Once Vertex and Kenwoodjoin the affray, I think it may be a hit, but then again, US hams have a long history of resisting change. It took HOW LONG for most old gasbag farts to STFU and accept the fact that tone squelch (aka PL), a 30+ year old analog signalling format, should be the norm on FM repeaters ? I rest my case.

As a sidenote though, the poor freq response and "watery digital sound" of IMBE CAI/P25 makes it unfit for sending signgalling tones such as DTMF and singletones/dual call/QCII however Icom tested the D-star radios using the AMBE vocoders and it had no trouble sending DTMF and other audio tones reliabily.

[mancow]

quoting ASTROMODAT- "We also have a huge spectrum shortage problem in the US that is worse than Japan's spectrum situation. "


I tend to disagree. I think it's a spectrum management problem.

There are vast chunks of spectrum sitting absolutely silent in most of the nation.

Look at the Vhf and Uhf low Fed bands. Does the FBI really need hundreds of frequencies assigned to them? Why not do it like the DEA. Assign a plan and keep it the same everywhere.

In most places you can search those ranges for weeks and maybe get one or two hits. Those are just two chunks of spectrum as an example.


Also, I wonder what's going to happen to vhf low when everyone finally leaves? It's not really much good for anything. Will the military just sit on it and that's the end of it?

[ASTROMODAT]

The poor freq response and "watery digital sound" of IMBE CAI/P25 makes it unfit for sending signgalling tones such as DTMF...

P25 with IMBE does NOT directly encode/decode DTMF tones through its IMBE DVSI vocoder. Instead, it sends DTMF as a packet data stream in a P25 standard format known as Data 12 (which are unacknowledged packet data). You simply punch in (real time) the DTMF codes via the touchpad on your XTS-5000 and/or XTL-5000---no problem, and the user transparently thinks he is sending DTMF. He is actually sending Data 12 packets that represent the relevant DTMF codes.

Data 12 works much better and far more reliably than analog DTMF, especially under weak signal conditions, and there is no DTMF falsing problems like you have with analog DTMF over analog FM systems. The DIU 3000 encodes DTMF into Data 12 packets, and it decodes Data 12 packets back into analog DTMF.

This way, you can connect your MRTI 2000 patch, and or a repeater controller, to the DIU 3000 and have a completely secure AES phone patch (for non-Ham use, of course). We have a controller hooked up to our Qunatars via the DIU 3000, and it automatically ID's, and the like, in analog or IMBE. The DIU 3000 auto tracks the nature of the incoming mixed mode traffic so the outgoing voice announcements from the controller go out in analog or IMBE, depending on the real time/on-the-fly nature of the mixed mode incoming traffic.

The "magic" of all of this depends upon the DIU 3000, which is necessary to make those Quantars really sing. This is just one example of the tons of cool things that the Quantar can do with the DIU 3000 and the latest firmware load.