[amsat-bb] Re: Icom D-Star

Tony Langdon vk3jed at gmail.com
Fri Apr 22 14:58:05 PDT 2011

At 06:06 AM 4/23/2011, Gordon JC Pearce wrote:

>No, but transmission using secret codes is.

Assuming the purpose is to obscure the meaning of the message.

>How, *exactly*, does DStar work?  Be sure to include a full and accurate
>description of how each frame of audio is compressed...

No need to, there is a device readily available on the market that 
will decode the audio for you, complete with data sheets, so anyone 
with the relevant technical knowledge can build an AMBE decoder (and 
some have).  The purpose of the audio coding is compression.  While 
the algorithm is protected by patents, and the only economic way to 
license it is to buy a chip from DVSI, they are readily available, as 
is the documentation.  And of course, if that's all too hard, you can 
simply go to your local ham store and buy a D-STAR radio (as can the 
authorities), or buy a DV dongle.

Your argument doesn't make sense, and I've clearly shown that the 
purpose of AMBE is not to "obscure the meaning of the message", but 
to facilitate communication, with means to decode it readily 
available off the shelf.  I certainly don't need any encryption keys 
to decode D-STAR, just the right hardware. :)

73 de VK3JED / VK3IRL

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