Do we think that anyone other then Icom will ever support the mode? I'd love to experiment with it on the birds but until there is competition to drive the price down will that be possible.

Maybe a GNU project?

Dave WB7DRU Minnesota

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of ka3hsw@att.net Sent: Sunday, June 08, 2008 9:53 AM To: amsat bb Subject: [amsat-bb] Re: D-STAR experiment on Cubesat

Successful D-Star contacts have been made on AO-27... see www.ao27.org

73,

George, KA3HSW

----- Original Message ----- From: "Satoshi Yasuda" 7m3tjz@jk1zrw.ampr.org To: amsat-bb@amsat.org Sent: Sunday, June 08, 2008 8:47 AM Subject: [amsat-bb] Re: D-STAR experiment on Cubesat

Hi Giulio and All,

...

my questions are:

what do you think about this experiment? and, is it possible to use this digital protocoll on a satellite (cubesat) ?

Yes, it is possible. Because the RF protocol of D-STAR is 4800bps GMSK (with BT=0.5) on FM mode.

Satoshi Yasuda 7m3tjz

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On Jun 8, 2008, at 9:18 PM, David Donaldson wrote:

Do we think that anyone other then Icom will ever support the mode? I'd love to experiment with it on the birds but until there is competition to drive the price down will that be possible.

Maybe a GNU project?

Dave WB7DRU Minnesota

Sadly, it's basically impossible to make a software version which interacts with D-Star because of the fact that the vocoder they chose to use is encumbered by patents. This is one of the principle reasons that I can't generate any enthusiasm for D-Star, despite having a number of interesting capabilities that would be useful for amateur radio.

The Wikipedia page sums it up pretty well:

D-STAR has been criticized for its use of a patented, closed-source proprietary voice codec (AMBE). [4] Hams do not have access to the detailed specification of this codec or the rights to implement it on their own without buying a licensed product. Hams have a long tradition of building, improving upon and experimenting with their own radio designs. The modern digital age equivalent of this would be designing and/or implementing codecs in software. Critics say the proprietary nature of AMBE and its availability only in hardware form (as ICs) discourages innovation. Even critics praise the openness of the rest of the D-STAR standard which can be implemented freely. An open-source replacement for the AMBE codec would resolve this issue.

The problem as I see it is that there really aren't a lot of choices for low bitrate audio coders. LPC is of course a possibility, and is free from intellectual property encumberments, but it makes everyone sound like a speak n' spell. The speex codec is open, but doesn't really work down into the 2400bps that we'd like to have. There aren't a lot of other choices that I'm aware of. It sure would be nice to find one though: with all the experimentation with SDR, digital voice could be a no-cost addition to radios, and a rich environment for experimentation.

Mark

On Jun 9, 2008, at 8:55 AM, David B. Toth wrote:

At 01:59 AM 6/9/2008, Mark Vandewettering wrote:

...

Sadly, it's basically impossible to make a software version which interacts with D-Star because of the fact that the vocoder they chose to use is encumbered by patents. This is one of the principle reasons that I can't generate any enthusiasm for D-Star, despite having a number of interesting capabilities that would be useful for amateur radio.

Mark: I had raised some of the same concerns as you have, but let us put this into perspective. We (hams) needed something in the form of a chip to go into portable radios. It already existed in the form of a chip that does AMBE, and it IS cheap (less than $20) ...

Yes, I understand. It's not a miserable state of affairs, but it's not great either. I'll expound more at the end.

Even if ham radio had waited for an Open Source Vocoder, we still would not have it and certainly not in chip form.

Other manufacturers CAN get the chip, there is no lock on it. In fact, Kenwood makes a D-STAR radio in Japan, like the ID-1 ...

It is my understanding that it is simple a relabeled Icom radio. If it really weren't an issue for other manufacturers, one might reasonably ask why we aren't seeing D-Star radios from other manufacturers. Granted, there could be other reasons, but something is apparently keeping other manufacturers from building these radios. This means that essentially we are in a single source situation, where we can expect D-Star to remain fairly expensive. Indeed, the codec chip costs $20, but we see the price differential for these radios to be well over $100, even on an HT which is fairly expensive to begin with. That's a pretty high markup. (IC-91AD is $524, IC-91A is $408 at universal radio). The UT-118 to do an upgrade is $189. The DV- Dongle is $200.

That being said, I know that Bruce Perens is pushing for an Open Source standard for HF and VHF (different ones if necessary) and I agree we should work towards that goal. That does not mean that we should categorically ignore D-STAR ... as others have pointed out, almost EVERY development in radio was patented, and in comparison, this is nothing. If I recall correctly, people had to pay royalties to build regenerative receivers, and that didn't stop anyone.

I don't think I actually said we should ignore D-Star. I merely said that it didn't capture my own enthusiasm. If it captures yours, by all means, do whatever you desire to advance it. There is little doubt that if, say, your own reason for being in amateur radio is EMCOMM, that D-Star gives you some nifty capabilities at a reasonable cost and with reduced bandwidth requirements, and we shouldn't be especially afraid of these radios.

But I do think there are reasons to be less than fully happy.

1. We have committed ourselves to building a system with parts from a single manufacturer. On this list, we have heard that Kenwood is unable to build new TH-D7As because they can't get a part which is single sourced, only 10 years into its lifetime. It doesn't seem to me to be good engineering to design our repeater systems around such a part, given our expected longevity for repeaters. I admit, this concern is largely paranoia, but paranoia pays off occasionally.

2. We are denying ourselves an opportunity: the opportunity to understand, modify, and create new digital voice systems. If we go to using AMBE, we are stuck: stuck with a technology that we can't extend or expand because of IP property law. Indeed, we will have invested considerable sums of money in such a system, which will present a serious impediment to future developments, since we will have so much money already invested in the old system.

3. Gadgets like the DV-Dongle cost $200, and you hook them to your PC. Your PC could do _everything_ that the DV-Dongle does in software (obviously, since the AMBE chip is just a low end TI DSP, mask programmed with the AMBE decoder). Imagine how much higher the deployment of D-Star would be if we could have a freely available open source application that people could run on their Windows, Mac and Linux machines for _zero cost_. As Gordon Bell once said (paraphrasing from memory) "the cheapest part of a computer are the parts that aren't there". Replacing a $20 with, well, nothing but electrons is a big deal.

Bruce echos most of these issues on his page:

http://codec2.org/

Mark KF6KYI

Your mileage may vary ...

Dave

VE3GYQ/W8 Spencerville, OH

On Mon, Jun 9, 2008 at 7:48 PM, Tony Langdon vk3jed@gmail.com wrote:

At 03:35 AM 6/10/2008, Mark Vandewettering wrote:

...

It is my understanding that it is simple a relabeled Icom radio. If it really weren't an issue for other manufacturers, one might reasonably ask why we aren't seeing D-Star radios from other

I believe you are correct there, a rebadged ID-800, according to what I've read.

...

manufacturers. Granted, there could be other reasons, but something is apparently keeping other manufacturers from building these radios. This means that essentially we are in a single source situation, where

Only the other manufacturers can answer that. The situation certainly hasn't stopped ham experimentation, and there has been at least one somewhat D-STAR capable radio built (there were issues, but they were related to the specific components chosen). There is a software based D-STAR demodulator (http://groups.yahoo.com/group/dstarsoftware) that apparently works quite well, when connected to a 9600 bps capable radio. Of course, a DV Dongle is needed to recover the audio, but the software will decode the headers and the low speed data stream. Transmit is just a matter of the author getting around to writing that capability. At this stage, he has been focusing on improving the receive performance of his demodulator.

...

we can expect D-Star to remain fairly expensive. Indeed, the codec chip costs $20, but we see the price differential for these radios to be well over $100, even on an HT which is fairly expensive to begin with. That's a pretty high markup. (IC-91AD is $524, IC-91A is $408 at universal radio). The UT-118 to do an upgrade is $189. The DV- Dongle is $200.

I suspect that will change with time, if (or more likely, when)

...

But I do think there are reasons to be less than fully happy.

1. We have committed ourselves to building a system with parts from a

single manufacturer. On this list, we have heard that Kenwood is unable to build new TH-D7As because they can't get a part which is single sourced, only 10 years into its lifetime. It doesn't seem to me to be good engineering to design our repeater systems around such a part, given our expected longevity for repeaters. I admit, this concern is largely paranoia, but paranoia pays off occasionally.

You have a point. The true single source issue is not ICOM, it is really DVSI. We can fix the ICOM part ourselves over time, with DV adapters and surplus FM radios with direct discriminator/modulator access. The controller might be trickier, but not beyond our capabilities, given time.

...

2. We are denying ourselves an opportunity: the opportunity to

understand, modify, and create new digital voice systems. If we go to using AMBE, we are stuck: stuck with a technology that we can't extend or expand because of IP property law. Indeed, we will have invested considerable sums of money in such a system, which will present a serious impediment to future developments, since we will have so much money already invested in the old system.

We are stuck with AMBE... for now. Perhaps in the future, there will be a way to incorporate other (i.e. open source) vocoders alongside AMBE. However, the developers will also need to push to get the vocoder into silicon fairly rapidly, once it's performing acceptably, so a manufacturer can produce the chips in the millions for installation into radios. The ideal vocoder will have readily available and unencombered software (for running on a PC) and hardware (i.e. DSP chip for installing into a radio) implementations.

...

3. Gadgets like the DV-Dongle cost $200, and you hook them to your

PC. Your PC could do _everything_ that the DV-Dongle does in software (obviously, since the AMBE chip is just a low end TI DSP, mask programmed with the AMBE decoder). Imagine how much higher the deployment of D-Star would be if we could have a freely available open source application that people could run on their Windows, Mac and Linux machines for _zero cost_. As Gordon Bell once said (paraphrasing from memory) "the cheapest part of a computer are the parts that aren't there". Replacing a $20 with, well, nothing but electrons is a big deal.

In an ideal world, yes. I believe we need to work with what's there now, and at the same time push for a better future.

...

Bruce echos most of these issues on his page:

    http://codec2.org/

Unfortunetely, he does get a few critical technical details wrong, if he is interesting in writing a vocoder compatible with D-STAR. Such a vocoder needs to (1) compress voice down to 2400 bps (not the 5000-6000bps he states for VHF), and (2) provide FEC, as the D-STAR protocol itself doesn't provide FEC. The difference in bit rate between 5000 and 2400 bps is a world of difference for performance. Of course, we can always use LPC-10 and sound like Daleks... ;)

73 de VK3JED http://vkradio.com

I appreciate very much this civilized debate, which helps me understand the issues involved in this new technology. I, too, find it frustrating that this protocol has no prospect for an in-software codec as of yet, but I understand the practical trade-offs that led to this situation. I wonder if people who are aware of the design could comment on if LPC-10 could theoretically be put ontop the transport layer. I'm not sure I'd mind 'sounding like Daleks', at least for the purpose of operating this cubesat.

Secondly, does anyone know which d-star radios have CAT, and does the CAT control line conflict with the data line, as it does on the Kenwood radios? If this were the case, I'd be inclined to stick with the Dongle approach.

At 01:35 PM 6/9/2008, Mark Vandewettering wrote:

It is my understanding that it is simple a relabeled Icom radio. If it really weren't an issue for other manufacturers, one might reasonably ask why we aren't seeing D-Star radios from other manufacturers. Granted, there could be other reasons, but something is apparently keeping other manufacturers from building these radios. This means that essentially we are in a single source situation, where we can expect D-Star to remain fairly expensive. Indeed, the codec chip costs $20, but we see the price differential for these radios to be well over $100, even on an HT which is fairly expensive to begin with. That's a pretty high markup. (IC-91AD is $524, IC-91A is $408 at universal radio). The UT-118 to do an upgrade is $189. The DV- Dongle is $200.

Well, those prices seem high but I guess the recent price increase pushed things up to compensate for the drop in the US dollar. The 91AD was less than $350 at Dayton so your price seems too high. I got a 92AD for $516 ... I just checked the price of the 91AD at HRO and it is $434.95, so you need to shop elsewhere I guess.

But to be fair, you need to use the Universal site properly. The LIST price for the 91AD is $524 - you need to push the button and see that their price is $399.95 ... I don't want to start an argument here but a big part of your argument surrounds cost and you are presenting VERY inflated prices to back your argument.

I understand all of your other points but do not believe that these are show-stoppers. If you are quoting Universal prices, you may live near Columbus .... they apparently have a D-STAR system on down there so you can check things out.

73, Dave VE3GYQ/W8 Spencerville, OH

Some options are becoming available...

An open codec like Speex COULD run in the existing D-STAR protocol...

http://www.speex.org/

On Mon, Jun 9, 2008 at 8:55 AM, David B. Toth ve3gyq@amsat.org wrote:

Even if ham radio had waited for an Open Source Vocoder, we still would not have it and certainly not in chip form.