Icom D-Star?

bellersley · Post by **bellersley** » Wed Nov 22, 2006 6:47 pm

I saw a thread on another website about a new DSTAR repeater in the Toronto (Ontario) area. I was wondering if anyone has any audio samples of this technology? I'm curious how it stacks up to P25 IMBE.

tvsjr · Post by **tvsjr** » Wed Nov 22, 2006 6:56 pm

It's about the same. It uses a better codec (AMBE2020), but the effective data rate is 3.6Kbps instead of 9.6Kbps for P25.

DPL · Post by **DPL** » Thu Nov 23, 2006 9:52 am

http://www.lubbockradio.net/D-STAR-vs-FM.mp3

This is the best (only?) sample that I have found on the 'net.

As tvsjr said, it sounds about the same as P25. I tried it out at Dayton and I thought it was pretty good sounding.

bellersley · Post by **bellersley** » Thu Nov 23, 2006 9:59 am

That doesn't sound too bad at all. I'd be curious to see a "real world" test where you have two people at a distance (IE, on the fringe) both using a D-Star radio and an ASTRO radio.

tvsjr · Post by **tvsjr** » Thu Nov 23, 2006 10:28 am

bellersley wrote:That doesn't sound too bad at all. I'd be curious to see a "real world" test where you have two people at a distance (IE, on the fringe) both using a D-Star radio and an ASTRO radio.

Done it, on simplex anyway. Relatively similar results. Again, I believe the GMSK used by Icom gives it some advantages on the fringe, but the FEC used in P25 is substantially better. I'd do more tests, but I don't have a Quant on the air (yet).

Wowbagger might have some thoughts too.

mr.syntrx · Post by **mr.syntrx** » Thu Nov 23, 2006 10:32 pm

I'd be interested to find out what mode Icom operates their vocoder - ie how many bits per second are data, and how many are FEC.

I have three AMBE2020 chips in wirewrap adaptors here to play with. Just waiting on some codecs to show up as well.

I saw something in an XTS5000 price sheet a while ago about operating in a 3.6kbps mode - what's the go with that?

tvsjr · Post by **tvsjr** » Fri Nov 24, 2006 12:24 am

mr.syntrx wrote:I'd be interested to find out what mode Icom operates their vocoder - ie how many bits per second are data, and how many are FEC.

I have three AMBE2020 chips in wirewrap adaptors here to play with. Just waiting on some codecs to show up as well.

I saw something in an XTS5000 price sheet a while ago about operating in a 3.6kbps mode - what's the go with that?

2.4Kbps voice, 1.2Kbps FEC (for voice only), 1.2Kbps serial data (no error correction - must be done at the application layer.)

On the 5000, I bet you're referring to operating on a 3.6Kbps control channel trunked system (old Type II/SmartZone/etc. control).