D-Star with gnuradio?

Hi people,
Have anyone successfully built a D-Star transmitter with gnuradio
blocks?

Best regards,
Rafael D.

schrieb Rafael D. on 2011-01-08 03:30:

Hi people,
Have anyone successfully built a D-Star transmitter with gnuradio blocks?

For the protocol part, see the archives[1]. IMO D-Star is a thing to
make money rather than a system to foster independent communication.
There are legal, privacy and free implementation issues.

For the codec parth D-Star uses AMBE+ as codec, which is non-free. You
can buy codec ICs, but you cannot implement it in Open Source. See the
archives again for a discussion.

Have a look at “codec2” [2], this should work fine for quite the same
requirements: low NF bandwidth, low bitrate, low latency.

Regards Patrick

[1]
http://search.gmane.org/?query="d-star"&author=&group=gmane.comp.gnu.radio.general&sort=relevance&DEFAULTOP=and&xP=d star&xFILTERS=Gcomp.gnu.radio.general---A
[2] http://www.rowetel.com/blog/codec2.html
[3] http://codec2.org/

Hi Patrick,
Thanks for the answer.
I know about codec2, but how about what modulation to use?
I read about the AOR ARD9000MK2[1] modem, that uses the:
“G4GUO open protocol”.
Do you know if is possible to implement this OFDM based one?

Best regards,
Rafael D.

[1] - MOVED | AOR U.S.A., INC. Authority On Radio Communications

schrieb Rafael D. on 2011-01-09 03:56:

Hi Patrick,
Thanks for the answer.
I know about codec2, but how about what modulation to use?
I read about the AOR ARD9000MK2[1] modem, that uses the:
“G4GUO open protocol”.
Do you know if is possible to implement this OFDM based one?

Unfortunately I could not find any document that describes the G4GUO
protocol. Would be very interested too.

From MOVED | AOR U.S.A., INC. Authority On Radio Communications I got:

Modulation method: OFDM
Band width: 300 Hz - 2500 Hz, 36 carriers
Symbol Rate: 20 mS (50 baud)
Guard interval: 4mS
Tone steps: 62.5 Hz
Modulation method: 36 carriers: DQPSK (3.6K)
AFC: +/- 125 Hz
Error correction: Voice: Golay + Hamming
Video/Data: Covolution + Reed-Solomon
Header: 1 Sec. 3 tones + BPSK training pattern for synchronization
Digital voice: AMBE2020 coder, decoder
Signal detection: Automatic Digital detect, Automatic switching
between analog mode and digital mode
Video Compression: AOR original adaptive JPEGFrom

Seems not too far off to implement in Gnu Radio/USRP.

Patrick

Wow, G4GUO is great ham operator Charles B…
May be he is here in this mailing list, I don’t know.

Best regards,
Rafael D.

Video/Data: Covolution + Reed-Solomon


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