[amsat-bb] Re: D-STAR experiment on Cubesat

Mark Vandewettering kf6kyi at gmail.com
Mon Jun 9 10:35:15 PDT 2008

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:


	Mark KF6KYI

> Your mileage may vary ...
> Dave
> Spencerville, OH

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