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[aprssig] Mobile Packet Range

Scott Miller scott at opentrac.org
Mon Sep 17 14:58:52 UTC 2007


You still can't use it.  Either you pay an exorbitant licensing fee, or 
you buy their hardware, or you get sued.

I've got nothing against the AMBE codec.  I just don't think it has a 
place in amateur radio.  Check out the manual at 
http://www.dvsinc.com/manuals/AMBE-2000_manual.pdf - when was the last 
time you used a chip with a full-page, fine-print EULA?

Yes, there are dev kits.  With the SAME chips, enriching the same 
company, and you still can't implement the codec yourself.  At least 
with something like EVRC-B you can get DSP code, and it's standards-based.

I just can't understand how that black box requirement is acceptable to 
hams.  I suppose most hams have just grown to accept that their radios 
are full of things they don't understand as they've filled up with DSPs 
and FPGAs, but there are plenty of us who DO understand those things, 
and anyone can learn the details of how it works and duplicate it 
themselves given the time and inclination and a modicum of skill.

The fact that the FCC didn't object surprises me.  The fact that the 
ARRL didn't object disappoints me.  Better to ensure there are plenty of 
new easy-to-use digital radios on the market to keep up the interest of 
the masses than to worry about interoperability and home brewing, I suppose.

Scott
N1VG



Dave Baxter wrote:
> Lots of stuff if you follow the links at...
> 
> http://wiki.multimedia.cx/index.php?title=AMBE
> 
> Found by googling for AMBE, strangely enough.  Just one of dozens of
> hits.
> 
> Including as someone said, a source of dev' kits from the makers.  Dunno
> how much in $'s though.
> 
> With my limited knowledge of such things, there seems to be quite a bit
> of information as to how it all works in the patent details.   Someone
> will no doubt rev'engineer it in some time, then come up against a wall
> of suits no doubt waving writ's at them.
> 
> The chances are, that there are some very similar commercial AMBE based
> radios about, or soon to be about, "our" D-Star system could be a quick
> way for the makers to get them beta-tested world wide, and get some of
> the investment back.
> 
> I've not seen or heard a D-Star radio yet, but I have played with some
> GSM software based codec's, and you can get quite acceptable audio and
> low-ish bit rates with them (messing about over networks) but I have no
> idea how they would compare to an AMBE based system.
> 
> 73
> 
> Dave G0WBX.
>  
> 
>> -----Original Message-----
>> From: Scott Miller [mailto:scott at opentrac.org] 
>> Sent: Saturday, September 15, 2007 8:46 PM
>> To: TAPR APRS Mailing List
>> Subject: Re: [aprssig] Mobile Packet Range
>>
>> Or without paying money to either Icom or Digital Voice Systems.
>>
>> (Hint - you legally CAN'T do the latter.  Every voice D-Star 
>> radio has to have an AMBE codec.  You can't duplicate it, you 
>> can't disclose how it works even if you pay thousands of 
>> dollars for a license, and you can't reverse engineer it.  I 
>> can't think of ANYTHING more contrary to the spirit of 
>> amateur radio then a mode that depends on one critical piece 
>> that we're not ALLOWED to understand.)
>>
>> Scott
>> N1VG
>>
>> Joseph M. Durnal wrote:
>>> D-Star is great technology, but try putting a D-Star 
>> station together 
>>> for less than $100!
> This mail has been scanned by Palmer Cook Computer Services Limited.  www.palmercook.co.uk
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