Re: [Freetel-codec2] TDMA and digital voice

Hi Adrian, Totally agree about the SDR hardware getting cheaper, a good case in point is the limeSDR mini which has more than enough flexibility for any ham style project. https://www.crowdsupply.com/lime-micro/limesdr-mini#products-top Couple that with a rock64 and you could have a great low

Re: [Freetel-codec2] TDMA and digital voice

Hi Ross, My initial GSM tests were done in the 70 cm band with low power (0.5 W). I recorded them here: https://www.youtube.com/watch?v=LC3GH0vp-iQ After that, as suggested by some local amateurs who are also part of the regulations comittees here, I moved it in the 1.2 GHz band with increased

Re: [Freetel-codec2] TDMA and digital voice

Hi Adrian, I suspect that many of the people here use proprietary SDR hardware - if code is linked with an appropriate HAL (hardware abstraction layer) eg libosmosdr/GNUradio, then it is pretty easy to swap the USRP for a BladeRF, or LimeSDR, or any other SDR with suitable capabilities which

Re: [Freetel-codec2] TDMA and digital voice

Hi, I know talking about proprietary SDR devices is probably frowned upon on this list, but doing TDMA with a modern SDR, let's say the Ettus USRP, is fairly easy and there is a lot of open source code for ex. GSM. Myself, I have been running a GSM network in amateur bands to play with some

Re: [Freetel-codec2] TDMA and digital voice

..@cortexrf.com.au> > *Sent: *07 November 2017 09:20 > *To: *freetel-codec2@lists.sourceforge.net > <mailto:freetel-codec2@lists.sourceforge.net> > *Subject: *Re: [Freetel-codec2] TDMA and digital voice > > > > really good points Sam on slot timing and radios. > &g

Re: [Freetel-codec2] TDMA and digital voice

really good points Sam on slot timing and radios. whatever you guys do, just remember to keep the SYMBOL rate BELOW 1500 symbols per second if you want the thing to work well in hilly/ echoey terrain if the symbol rate is low enough, you can run simulcast easily... On the FDMA uplink- you

Re: [Freetel-codec2] TDMA and digital voice

Having had some experience with TDMA data protocols (not voice, just data), my 2 pence on this is that I feel you are considering far too fast a slot timing for most radios to cope with. Yes, SDR radios could cope with 300hz slot timing or whatever, but "older" radios with PLLs will struggle

Re: [Freetel-codec2] TDMA and digital voice

Ross, I really resonate with your desire to just jump right into the protocol its self, I've played around with many such ideas - it really is fun to dream about what could be possible! But I had to realize I was getting ahead of my self though, for something to really gain traction like you are

Re: [Freetel-codec2] TDMA and digital voice

> would it be best to spin off a new forum for this topic? Probably not. The active members are so few, that nothing is going to get pushed off the top very fast. 73 -- Check out the vibrant tech community on one of the

Re: [Freetel-codec2] TDMA and digital voice

Regarding TDMA (for Codec2 +), would it be best to spin off a new forum for this topic? I think that it would be sensible to have both half-duplex TDMA (single RF frequency) and full-duplex TDMA (split frequency repeater) modes. This is because whilst half-duplex TDMA has the advantage of

Re: [Freetel-codec2] TDMA and digital voice

Brainstorming (no code, no circuit boards): If we are talking VHF (hopefully) then probably the 3200 vocoder is a better choice to get a better voice quality. This is 64 bits 50 times a second (20 ms frames). But that's just the voice. Obviously you want data and protocol as well. Say a

Re: [Freetel-codec2] TDMA and digital voice

Hi, I'm also working on some TDMA code (SDR based). There are a few issues. Codec2 frames are 40 ms which are a bit too long to fit into the slots (with guard times involved). Because code schedules radio bursts in the future and updates the scheduler clock every X frames, long delays are to be

Re: [Freetel-codec2] TDMA and digital voice

On 04/11/17 13:27, Alan Beard wrote: > In the DMR camp, in particular the TYT MD-380 and clones group, > we have a possible hand-held with downloadable firmware that > could support another codec. Good luck with that. It's theoretically possible, but I doubt the CPU in the MD-380 is brauny

Re: [Freetel-codec2] TDMA and digital voice

On 11/2/17, Paul Sperbeck wrote: > He mentioned a 'fusion' (not the yaesu kind) of digital voice and TDMA > that could be used to create single frequency repeaters. Having built a > set of cans years ago this looks like quite an advancement. ... > I don't have any coding

[Freetel-codec2] TDMA and digital voice

I was watching Bruce Perens on the DDC youtube from HRN. see: https://www.youtube.com/watch?v=giZi4Y7FlwM He mentioned a 'fusion' (not the yaesu kind) of digital voice and TDMA that could be used to create single frequency repeaters. Having built a set of cans years ago this looks like quite