Page 1 of 1

Diving Into GMSK on Arduino

Posted: Tue May 01, 2018 3:09 am
by kd4iz
Just starting to play with this. Looks like it is particularly for repeater/hotspot use. Was hoping that using Guus’ GMSK and AMBE 3000 shields together on an Arduino Mega board would get me to a local combo that would do the work of the MOENcomm *board for HF and up. If anyone has tried it and succeeded, it would ne good to know... TIA! Jack :geek:

Re: Diving Into GMSK on Arduino

Posted: Tue May 01, 2018 8:02 am
It really should work, the ABME add-on gives you and audio bridge to the GMSK board, remember that GMSK is D-Star only... so its going to be single mode if that is what you have.

Guus does answer e-mail, so if you are stuck, talk to him; remember that if the bridge is audio based, there is no callsign data available so its not really suitable for public use.

Hope that helps.

Re: Diving Into GMSK on Arduino

Posted: Wed May 02, 2018 10:13 pm
by kd4iz
Thanks Andrew,

Aware of the D-Star only bit. I am not much of a DMR user and don't have C4FM at all - my emphasis is really on non-voice digital modes and HF (including D-Star).

I have been in conversation with Guus sporadically about the idea. He indicated that he had planned to work on it a while back, but I also know that he has been very busy working on the DVMEGA dongle and the DVMEGA Cast radio. IIRC, his plan was to make it an option or offshoot of the Cast project firmware.

I believe that he is preparing to show and talk about those two projects at the Dayton Hamvention this year. Probably where his focus is just now, not on lower margin projects like this. We will get there.

BTW, I enjoyed eavesdropping on your conversation/interview with Steve the other day. Thanks for doing that, very interesting.

Jack - KD4IZ

Re: Diving Into GMSK on Arduino

Posted: Thu May 03, 2018 6:51 am
It's rare that I get time to spend on the radio, if you hear me on, dive in next time;

I am making the wild assumption here that what you want to do is take audio (ignoring the source for a moment) and wrap that up and push it to the D-Star network, that should be entirely do-able with the kits out there; if you are trying to go directly from RF sample to D-Star, then not so much.

Maybe you could elaborate a little more on what you plan to do, also have a look for videos by Michael, ZK5ZEA if memory serves, he had some good videos on doing almost exactly that on VHF/UHF.

I may well be barking up entirely the wrong tree here, so set me straight if that is the case.

Re: Diving Into GMSK on Arduino

Posted: Fri Jun 01, 2018 10:46 pm
by kd4iz
Been swamped with work and a few critical projects so just read your reply! Sooo far behind...

What I am trying to do is create a "D-Star modem device" that connects to the high speed modem port of an IC-7000. The purpose is to use the AMBE encoder/GMSK modem/separate mic and speaker to encode and decode a D-Star data stream. I could then use the 7000 in the shack in place of the 7100 (which I would like to move to my car).

In retrospect - I would certainly entertain using an RPi instead of the Arduino, but the shields were the hardware that Guus offered that looked like it would work. I just have been so busy that I have not even had time to look into the code that is out there. Hope Guus will have some bandwidth after the Friedrichshafen show is over.

I have another project about to arrive... I got a ship notice of the Northwest Digital XC-3006 multichannel DV board just yesterday, so cross-mode is going into the queue for a local club repeater cluster. Fortunately I have some friends that are excited about that project so I will probably just be the "benefactor".

Best 73,