Codec2 - Open Source DSTAR Digital Voice

The same thing happened during two world wars. After "The Great War" the Navy wanted all of the RF spectrum. After WWII (when we decided war was so much fun so we would number them) it took the amateur community several years to recover ground. Look at the old requirement for hams to have CONELRAD receivers at the operating positions.

All governments have a great distrust over the free exchange of information. The more repressive the regime the greater that distrust. Look at how many hams are licensed in North Korea (0).

Back to the topic;
We would be advancing the art if we were doing the research. When we just buy a mode (protocol) from a manufacturer we are merely consumers.

 

love it..

i remember all the bad things the am'ers said about this new thing called single sideband in the late forties and early fifties.. and some of them are still around convinced that AM sounds better, some never learn.. we shall see....love it... Elsie Kay

 

We all just use the internet now...except it's still ham radio because we use super special secret agent callsigns.

 

I admit I don't know much about Dstar so I have (2) questions about your reply about "More Secure System".

1) How does the use of dstar make a more secure system?

2) More secure from what or who?

K2WH

 

Something only an American could think, let alone say.

There is a world outside of the US, you know - and 11/09 didn't change Amateur Radio.

 

It's encrypted with a patented codec, making it illegal to listen unless you buy a radio or dongle containing the codec chip bought from AMBE.

Only secure from people who aren't stupid enough to pay a fortune to Icom (or a slightly smaller fortune to 2 other companies) for the equipment to listen.

 

Actually, you don't have to digitize the audio. FHSS hops frequencies and can be applied to an existing modulation, such as voice over FM.

Leigh/WA5ZNU

 

I already use frequency hopping, its called RTTY!!

K2WH

 

FYI Dstar is not encrypted, it is patented, however there is nothing preventing its reverse engineering, in the Public Safety radio communications front Harris (or Tyco, or Macom) have their AMBE codec called Provoice it as of last month has be reverse engineered through soundcard on a linux Machine

Digital Modulation can be encrypted but not always so breaking AMBE is not neccesarily illegal.

i am all for an open codec, however i am pro dstar but then again i look at this as a hobby, dont like dstar dont buy it, like dstar buy it

 

http://www.youtube.com/watch?v=sDUIU2rVn5s&playnext_from=TL&videos=ghyVuiyVLUc

G6LVB "G-Star" / Microchip PIC32 LPC10 codec demo with low bitrate 2.4kbps bitstream.

 

http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

This Digital Speech Decoder software package is able to successfully decode the audio from MotoTRBO and P25 Phase 1. The funny part is I was under the impression the IMBE vocoder used in P25 Phase 1 was also proprietary and licensed by DVSI.

So never say never.

 

BUt even with a codec you still need layers 2 through 5 right? The codec is just an application and since there is no encryption probably don't need layer 6 but maybe you do.

Looking at each layer:
Layer 1 Physical we have in analog FM transceiver.
Layer 2-5 we don't have
Layer 6 likely don't need, but maybe.
Layer 7 application is the codec.

Maybe everyone is looking at the system different but I would like to hear what everyone thinks about these different layers. The ICOM patent and the JARL standard generally deal with layers 2-5.

 

Apparently David Rowe has made an early release of Codec2, a new open voice codec intended to be a (incompatible) replacement for AMBE+. Currently it runs about about 2550 bits per second, the rate will probably fall with additional work. You can find the announcement and code at http://www.rowetel.com/blog/?p=839

Bruce Perens K6BP, will be presenting on this codec at the TAPR/ARRL DCC this month.

 

Is it going to be available to others "soon" ?