Proposal Draft: New Voice Codecs for Amateur Radio

Douglas Cole

Wed May 14 21:53:20 -0700 2008

Where and when will you be speaking? I would like to attend, but need to keep my schedule squared away.

Planning on being there with a couple friends starting Friday morning.

Speaking of digital modes, I am planning on getting active using some Project 25 capable radio's on Amateur frequencies.

I believe it is legal since the codec is known, or at least that is what many Amateurs are saying on the west side of the state (Washington)...

Hope to see you there.

Doug Cole

N7BFS

Proposal Draft: New Voice Codecs for Amateur Radio

Charles E Hill

Thu May 15 05:30:02 -0700 2008

Well, Hamvention is tomorrow, Saturday and Sunday in Dayton, OH, but I don't see Bruce listed on the Forums schedule for speaking.

Hmmm...I was supposed to drive home (Chicago) this weekend but Dayton is only 2 hours the other direction...

Charles
N3DEY

Proposal Draft: New Voice Codecs for Amateur Radio

wowbagger

Thu May 15 06:35:56 -0700 2008

IIRC Mr. Hollingsworth has said P25 CAI on the ham bands is OK - however, using any of the encryption is, of course, a big no-no.

And the legality of actually using a P25 trunking control channel is in question, as that could be taken as broadcasting.

Speex

Charles E Hill

Thu May 15 05:37:14 -0700 2008

The Speex modification sounds like the right track to take.  Especially since there is the possibility of one of the developers (David Rowe) doing some work as a hired consultant.

Does it really have to 100% match or beat AMBE, or is there a point where it would be "good enough" for general replacement?

Speex

wowbagger

Thu May 15 06:21:23 -0700 2008

Does it really have to 100% match or beat AMBE, or is there a point where it would be "good enough" for general replacement?

This is just my opinion, but I'd say that, considering the roles D*STAR and the AOR protocols are being used for, "good enough" is "intelligible speech" - after all, the AOR protocol competes against SSB, which distorts speech pretty badly if you and the TX station aren't exactly matched in frequency.

Let me stir up even more trouble, then

wowbagger

Thu May 15 06:50:52 -0700 2008

I'm really flattered that my concerns are shared by such notables in the Amateur Radio Service.

So let me lob another grenade into the fray: the issue of amateur fast scan TV and the sunsetting of NTSC in the US.

My radio club (The Wichita Amateur Radio Club) recently had a presentation on the NTSC -> ATSC conversion. While the speaker was more focused upon the sorts of questions non-hams would have had, we did have some technical questions (some of which I fielded). One of the questions was on how the end of NTSC would impact amateur FSTV.

AFSTV is important - as I type this, the Wichita River Festival is going on, and several members of WARC are (and have for several years been) providing assistance to law enforcement by stationing multiple cameras throughout the event, linked back to a command center by Amateur Radio, to help the cops see any trouble before it gets too bad. FSTV is used for emergency response, to give the EOC "eyes-on" the problems.

Today, it's no big deal to get a receive-only solution for FSTV - any TV set with a "cable" tuner setting (in short, just about any TV) will tune the 70cm band FSTV frequencies. However, what will happen in a few years when that is no longer true — when TV's no longer have NTSC tuners (yes, that will still be a few years due to cable and satellite, but 2012 isn't that far off.)

ATSC isn't really suited to what we hams do - I'd say it's pretty rare that we need to push a 1080i stream over the air. Also, it's bad enough trying to push a 4MHz wide analog VSB signal any distance - just imagine what it would take to push an 6MHz wide 8VSB signal. Then there is the whole problem of the patents on MPEG and AAC - while there may be Free software implementations of them, the use of those solutions without paying for the patents is not technically legal.

So it seems to me that, in addition to needing Free vocoders for voice operations, we hams need Free video codecs for FSTV. It seems to me that if you could take a standard definition 720x480i stream and bung it through Theora, you could get a low enough bit rate that, coupled with something like OFDM, we should be able to get a signal that is only 1MHz wide or less — which would bit much easier to push over the air.

Discussion?

Let me stir up even more trouble, then

AB3A	Fri May 16 04:12:52 -0700 2008

Umm, where does one start with this issue? There are all sorts of design parameters that haven't been discussed yet.

Frankly, I think that we ought to be working on standards for high speed data transmission in ham radio. We can always use various digital video CODECs such as MPEG.

The larger question is how we should modulate, whether any error correction coding may be used, and what protocols can be used over the air.

This is such a morass, that I feel we ought to just take it one layer at a time, and see who gets excited about what.

DE AB3A

Let me stir up even more trouble, then

wowbagger

Fri May 16 05:00:46 -0700 2008

OH, I whole-heartedly agree, voice first, then use the experience from that to move up the food chain.

But, my hope is to start people thinking about the issue now, so that when the time comes to tackle it we have thought about how best to begin.

Proposal Draft: New Voice Codecs for Amateur Radio

Dick York

Fri May 16 17:52:43 -0700 2008

I thought JARL (The Japanease Amateur Radio League) and NOT Icom is the sponsor of D-STAR?? They are like the ARRL (non-profit).   I think they call it "Digital Smart Technology Amateur Radio".  And why wouldn't an AMBE codec be "in the spirt" of AR?   Lots of commercial products get used.  Why not software?   "D-STAR Is anyone else worried" - I'm not!  Great product, price is right and the usage is coming WAY up.   Why try to stop a landslide when it's already over your head?  Used 91AD's are being had for under $250 now, you can't touch failing Motorola products for that,clunky feature(less) American technology. 

Exciting development has already occured with using D-STAR as a backbone.  Don't reinvent the wheel - go with the flow!  OR some smart ham geeks start building homebrew D-STAR gear and repeaters.