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 http://vkradio.com