D-Star – a Delight or a Disaster?

The D-Star system has both interested me and left me wondering since Icom brought it to the USA several years ago.

 The discussion at Jeff KE9V’s “CQ Calling” Blog D-Star Rising Article & Comments pointed out:

  • With only a computer dongle for a non-Icom option it appears that no other manufacturer sees enough market to launch a D-Star enabled product line.
  • While promoted as an open standard, we should be clear that D-Star is like Pactor II & Pactor III  (another closed single-source product) in that it is based on a closed proprietary CODEC.
  • Advanced Multi-Band Excitation (AMBE) is a very powerful proprietary speech coding standard developed by Digital Voice Systems, Inc. as a commercial product.
  • D-Star with the AMBE Licensing adds $150/$250 per radio unit – though the exact $ for DVS is a secret.
  • Though promoted as one system Icom’s D-Star implementation is a set of various Digital Voice and Digital Data systems on several different bands.  The capabilities and through-put vastly differs between the various implementations on each of the bands.
  • A D-Star user and D-Star systems are subject to complete denial of D-Star service through any of several layers of software administrative control.  No other amateur radio system is so completely at risk of being taken down by either a technical problem or deliberate action.
  • With much of the CODEC being licensed and not open for examination, D-Star is at its base level a “black box,”  making Amateur lead user improvements difficult.  This is much like building a new car that uses a special fuel only available from one manufacturer who won’t disclose what the fuel is.  

Other serious limitations are mentioned in the D-Star Rising article & comments, and in my previous D-Star posts (searcg box is on the right side of the webpage for this blog).

More simply the limitations of the D-Star system eliminates it from being a single sole configuration for the communication tasks.

A worthwhile experiment, but not one ready to replace other Emcomm options.





D-Star Rising by Jeff Davis KE9V

added June 30th:  D-Star Experiment Ended on Jeff KE9V’s assessment that D-Star is a Disaster.


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8 thoughts on “D-Star – a Delight or a Disaster?

  1. Christopher A. Bohn N0RZT says:

    Personally, I don’t plan to hop onto the D-Star bandwagon anytime soon. I have enough concerns that I’d like to see how things play out first.

    – It’s a one-dog show. Icom’s the only vendor selling D-Star equipment. I’ve heard of no one homebrewing D-Star equipment. The word “experimentation” seems to be limited to “let’s see how well it works”. This twitches my “risk” nerve… I don’t foresee widespread adoption unless Icom is willing to continue its promotions almost indefinitely or unless other vendors start playing. Microsoft generally can change the direction of the market because it’s the only 900-pound gorilla in its room; Icom may be the heaviest gorilla in its room (or might not be; I don’t know), but there are a couple of other sizy gorillas that keep it from achieving dominance.

    – It’s a little intellectually offensive. To me, at least; I suspect there aren’t many of my particular mindset. When I teach software design, I caution my students to minimize the “semantic gap” between the user’s world and the software design. In the context of radio, I think of semantic gaps between the message and the transmitted signal. AM and SSB, hands-down, have the least semantic gap. FM and PM don’t have that much greater of a semantic gap; that I can get someone studying for their tech license to hand-draw the approximate waveform for these modulations, or to re-construct the original message from the waveform, speaks volumes. Going to digital increases the semantic gap further still. In of itself, that’s not bad. Of course, each tweak to the encoding broadens yet the semantic gap, and the design tradeoff must always be considered: what do you get in return for the increased complexity? Going to FM, you get increased SNR over the short haul. Going from, for example, phonographs and tapes to compact discs buys you increased quality in the presence of physical damage; the designed-in loss in audio quality is beyond the range of human hearing. Going to MP3s introduces compression, and the loss of quality is beyond what my ears can detect. Compress it more, for example to “digital telephone”, and you’d better believe I can tell the difference! I’ve already heard that D-Star sacrifices the nuance-quality of the transmitted message; it has a wide semantic gap between the message and the signal; what does it gain us?

    – I’d like to know how it handles multi-path reflection. I’ve heard that the new “digital television” standard is horrible in the presence of multi-path. With analog, you’d get ghosts; with digital, you’d get a black screen. In a sense, this gets back to the semantic gap: the low semantic gap you have with vestigal sideband means that your brain can re-construct the original message despite the ghosts. When you’re working a station on SSB and there’s a weak overlaying signal, your brain can re-construct the desired message in the presence of the interference. I don’t think you’re going to get that with a digital signal. Of course, to be fair, FM isn’t exactly the poster child for tolerating multi-path reflection (as anyone who’s heard picket fencing can tell you).

    Chris N0RZT/8

  2. Jeff WA4ZKO says:

    I’m a repeater sysop myself and know many others. The going trend across the country is that most analog repeaters set silent 99% of the time. I can’t count the number of sysops that have told me they are going to run current gear till a major repair comes up, then it will fade away. Even SERA had an article in their journal magazine about “where have the users gone” not so long ago.

    So? Conventional repeaters are fading away one by one due to lack of activity. I just don’t see that the introduction of DSTAR repeaters is going to change this trend. We’ll just have more repeaters, even more expensive to install/maintain, setting around idle most of the time. Sure, you might get a burst of usage in the beginning that quickly fades as the “new” factor wears off. DSTAR has been around for several years now…nearly a decade?

    I find it interesting that only ICOM offers DSTAR gear and none of the other manufacturers have joined in after all these years. Plus when you factor in the poor quality of most ICOM gear of late, not good. In fact I gather DSTAR gear sales have been so poor they recently started all kinds of promotions. The only DSTAR system in my area is, interestingly, heavily sponsored (read subsidized) by the local ham radio gear dealer and ICOM.

    I’m also disturbed by the misinformation (outright lies at times) and exaggerations often used by the DSTAR crowd when it comes to “is this a repeater or not,” and the comparisons with APCO25.

    Then to build this on another proprietary CODEC is, IMHO, a big mistake. Why reinvent the wheel when a well defined digital standard already exists. It would of been much wiser to use a interoperable standard (ah, APCO25 anyone).

    Yeah, I know the codec is still proprietary JUST LIKE DSTAR’s. At least this would offer INTEROPERABILITY options for those that want to have commercial/ham channels in one rig..legally. Plus it would allow hams a great deal of choice in terms of obtaining commercial grade gear to be used for the repeaters…just like we do today with analog repeater hardware. ICOM’s repeaters have never been known to be a very good value and reliable.

    From what I’ve seen of it, DSTAR would be an administrative nightmare to use in a typical real world emergency. This is especially so if you’ve got users coming in from out of the area to assist and they are not already setup on the system. Not to mention the potential for system failure with such a setup. The audio quality of DSTAR leaves a lot to be desired in comparison to just about any P25 radio I’ve used. The P25 commercial gear is unarguably much more durable than ICOM’s toys anymore.

    In many cases, APCO25 gear can do both analog and digital. DSTAR repeaters (sorry, a repeater is a repeater) are digital only. Yes, the mobiles/handhelds can do analog FM and DSTAR, but not the repeaters. Granted you probably wouldn’t want to be doing both on the same system on a daily basis, but it’s a nice fall back option to have there. AKA, flexibility.

    Before someone comments that APCO25 locks you in to Motorola gear, it just isn’t so. You can buy all kinds of APCO25 gear from a multitude of manufacturers. APCO is a public safety group that defined the standard, a standard created with a lot of thought towards the future, interoperability, and preventing vendor lock in. We hams don’t know it all and could learn a lot from today’s communications leaders and pros.

    Most hams are just glorified appliance operators anymore. That’s not always a bad thing, everyone is in the hobby for their own reasons. Problem is that many need to learn just how far behind the rest of the communications world we are. A great example was the hoopla created when SERA tried to get the 2m repeater owners to adopt PL tones (something public safety adopted decades ago). Yeah, the way SERA went about it didn’t help, but to read the rational behind the resistance to it was an eye opener for many as to why our hobby stands where it is today. Even Riley Hollingsworth made comments that made it clear we needed to get at least halfway in sync with the rest of the communications world!

    Many of your repeater owners are going to want to carry commercial gear on their hip, not a 2nd radio just to work DSTAR. It would of been much better to take the existing digital standards and design for interoperability. I’ve been around a lot of this group and they are not impressed the DSTAR gear and choices made. Digital is the future for sure, but implementation is key.

    If they wanted a data layer, then strap it on top of an existing standard and allow backward compatibility to APCO25. This layer should be completely open and extensible. Let us hams do what we used to do best…innovate. Seems we didn’t learn much from Katrina and 911.

    No I’m not saying that the average ham needs to be able to access a local public safety system via APCO25 using ham gear. In most, if not all cases this would be illegal for a variety of reasons. But what many need to realize is just how many hams that are active in public service are also employed in public safety. As radio systems are upgraded across this country, guess what’s replacing them? APCO25 gear. Many of these guys/gals are already carrying high quality APCO25 gear on their side are not going to go for yet another expensive digital radio because ICOM couldn’t go with a standard. Hence ICOM immediately lost themselves a good chunk of users, users that are often the front and center face of ham radio to the agencies we serve. Give this some thought folks.

    From what I gather from my travels and talking with other repeater sysops, most hams going digital are deploying P25 commercial grade gear. These P25 repeaters are seeing more interest/usage than comparable DSTAR repeater systems, but even they admit that usage is nothing compared to the 80’s and 90’s. In general the attitude from these guys is that if you’re going to do digital repeaters, then you do it right and use an open standard like P25. Yeah, P25 stuff is expensive, but DSTAR isn’t cheap either. Both will come down over time and P25 surplus gear is already pretty easy to find on ebay.

    Many other concerns about DSTAR exist, but I think just the above will prevent it from ever being anything more than a niche toy. The sad part is that if it had been done right, we wouldn’t be closing in on nearly a decade of DSTAR with so little actual usage beyond a few highly vocal niches.

    Both DSTAR and APCO25 are interesting technologies with pros and cons both ways. In the end things will have to stand on their own merit, not hype. I predict ICOM and the DSTAR folks are going to regret their choices.


    • APCO P-25 uses the IMBE vocoder, which is the older version of the AMBE decoder, used by D-STAR. IMBE is no more open then AMBE. D-STAR was created by the Japan Amateur Radio League and is open source with the exception of the proprietary vocoder, which, yes, is a big drawback, but as you said… why reinvent the wheel? The vocoder is actually just a very small part of what makes the radio work. The entire D-STAR standard is otherwise published and any manufacturer can jump in at anytime. It’s still pretty early in the ballgame.

      D-STAR was created with amateur radio operators in mind. P-25 was not. Callsign routing, callsign display, on-screen messages and the D-PLUS add-on suite (plus more) demonstrate that fact. It offers so much more for amateur radio operators that P-25 doesn’t. What does P-25 bring to the table? Digital voice. Not much else for amateur radio operators to enjoy unless you’re made of money.

      It’s also worth noting that yes we can innovate and enhance this open digital radio standard — the D-PLUS suite was created by one ham, AE5PL, to enhance D-STAR. He wrote the gateway software for D-STAR. Why? Because it’s open-source and we’re hams! Reflectors and repeater linking? That’s all him, not Icom, not JARL, not the ARRL. That’s all from a ham like you and me.

      There’s no reason for D-STAR to need to be interoperable with P-25 (read: public safety). What a silly reason to complain that you can’t put D-STAR systems in your commercial portable side-by-side with public safety P-25 systems. Who would really have a reason to do that? It would be an extremely small subset of users who would want that capability that it would not be feasible for D-STAR developers/manufacturers to let that hold them back from what D-STAR is today. D-STAR is meant to be a tool, but it isn’t used only by emcomm operators. It’s actually few and far in between for D-STAR to be used in emergency drills or actual emergencies so far. But, like I said, it’s still early in the ballgame.

      P-25 Phase II standard is actually set to use the AMBE vocoder — yes, that’s the same vocoder as D-STAR.

      “From what I’ve seen of it, DSTAR would be an administrative nightmare to use in a typical real world emergency. This is especially so if you’ve got users coming in from out of the area to assist and they are not already setup on the system. Not to mention the potential for system failure with such a setup.”

      Wait, what? What if you have P-25 users converging on a disaster area with their commercial rigs and they don’t have the local frequencies programmed into their commercial radios? Talk about an administrative nightmare! Those radios would be useless. In some areas it’s downright difficult to find an authorized vendor to program ham frequencies in a Motorola radio, let alone on the fly. Sure, front-panel programmable P-25 radios are becoming more available as surplus, but that’s only if you want to feel like spending a shade under $1,000 for the ability to program frequencies on the fly — something D-STAR equipment already does by nature.

  3. Christopher KI4YMD says:

    I agree with this message.

    My reluctance on jumping on with the other hams in my area has to do with single source and price. I do not like the fact that ICOM is the only game in town.

    Watching the “giving away” of repeaters by HRO and ICOM, I can see the way to sell radio gear. I joke with my pals and say that if you want to sell gear just push it on ARES. Then any nobody who wants to be a somebody will buy your radio :) ICOM is marketing D-Star as a “standard” for emergency communications. It is a tool. Just like Analog FM, HF, 802.11b, etc.

  4. Matt Bush KA9RIX says:

    D-Star is a disaster just like other digital formats. The real problem with all these systems is their inability to recover from a fade. They do not process in real time. Once in a fade they produce R2D2, not simply some noise that the human ear and brain can immediately recognize which allows the user to instantly react to. The Codec doesn’t know the difference between data and noise so it just continues spewing garbage.

    D-Star, P-25, MaCom- all garbage…

    • Brian N0ZSG says:

      Matt you don’t know what you are talking about. Fade and Multipath are 2 different things. Also you mention D-star, P-25 and MaCom.All Garbage. MaCom is a manufacturer not a technology. Also when people start comparing Digital TV to P-25, I know they havent a clue. I use it and work on P-25 everyday. And I can’t stand to listen to analog anymore. Digital really is all it is cracked up to be. Just my 4 cents. Don’t mean to slam you matt just had to be said, when you say digital is garbage in general terms.

      PS. P-25 does recover from fading, very nicley I might add.

      It would be in the public saftey sector if it was garbage.

  5. Matt Bush, Ka9rix says:


    You are right, P-25 does recover nicely. Multipath and fading have the same effect on the processor, P-25 recovers but the M/A-Com Pro-voice and D-Star do not.

    P-25 using the IMBE vocoder doesn’t seem to function with noise, whereas analog does. Numerous agencies have complained about this and many have switched back to analog.

    I personally want to build P-25 ham repeaters when the prices drop…

    I wish ICOM and Kenwood would make P-25 radios for hams…

    Thanks for your comments,

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