On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why can't people
be left to enjoy their pet facets while others get on and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Yeti wrote:
On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why can't people
be left to enjoy their pet facets while others get on and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Over here it is probably the mode with the most experimentation going
on in ham radio today...

Of couse not with the codec.
But in any communication system there are things that cannot be changed
or incompatability would result.
That does not mean there cannot be experiments elsewhere in the system,
or in the application of the system as a whole.

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time. It was very clear that
a couple of critical mistakes were made in the design, and there were
proposals on how to fix them, but they never took off as it simply
wasn't practical to change AX.25
It really made no difference if it was open or closed, it was unchangable
anyway.

Yet, amateurs used it as a black-box building block in many applications
and experimented a lot with it.

On 24 Sep 2010 16:34:08 GMT
Rob wrote:

Yeti wrote:
On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why
can't people be left to enjoy their pet facets while others get on
and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Over here it is probably the mode with the most experimentation going
on in ham radio today...

Of couse not with the codec.
But in any communication system there are things that cannot be
changed or incompatability would result.
That does not mean there cannot be experiments elsewhere in the
system, or in the application of the system as a whole.

Remember packet. The AX.25 protocol was open, but it could not
really be changed because that would break compatability between the
many implementations that existed after some time. It was very
clear that a couple of critical mistakes were made in the design, and
there were proposals on how to fix them, but they never took off as
it simply wasn't practical to change AX.25
It really made no difference if it was open or closed, it was
unchangable anyway.

Yet, amateurs used it as a black-box building block in many
applications and experimented a lot with it.

And ultimately it failed (what's left of the packet network is a shadow
of what it was) because of that lack of flexibility.

Amateur radio has a difficult-to-overcome problem in that we always
build systems from the bottom up and don't design in the features that
allow growth and variation. D-STAR is another example of a system that
shares that same fault.

I hope that it's possible to create something that doesn't have these
limitations, provides better function and allows more experimentation
with all aspects of the technology.

--

Brian Morrison

"Rob" wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.

--
73
Brian G8OSN/W8OSN
www.g8osn.net

On Fri, 24 Sep 2010 18:08:15 +0100
"Brian Reay" wrote:

"Rob" wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not
really be changed because that would break compatability between
the many implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will
be limited- unless they only want to talk to themselves or with
others they've co-ordinated experiments with.


Well the plan is that eventually any closed system becomes out evolved,
so the advantages of the open alternative become available to all. I am
more than happy to share, DVSI are not.

--

Brian Morrison

In article ,
Brian Reay wrote:

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.

Seems to me there's plenty of opportunity for flexibility with regards
to codecs. The protocol could be designed to allow for negotiation of
a common codec between two radios - start out with a simple
"universal" codec to get the communication started, and then
optionally switch to a different one.

Something like this is done in the commonest voice-over-IP protocol
family (SIP). There are numerous codecs available, ranging from
bog-standard telephony-style (uLaw and aLaw), to simple linear PCM, to
ADPCM, to various forms of sophisticated coding and compression. Some
of these require paid licenses (e.g. G729), some come with a
commercial- but-free license (e.g. ILBC), some are based on patents
which have now expired and can be implemented freely (e.g. versions of
GSM), and some are aggressively open-source and free-as-in-
speech-and-beer (e.g. Speex).

Protocol negotiation becomes tricker when you're dealing with a
repeater system, or a more-than-two-way simplex conversation, but
that's where the fun and experimentation comes in!

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Fri, 24 Sep 2010 10:42:10 -0700
(Dave Platt) wrote:

Seems to me there's plenty of opportunity for flexibility with regards
to codecs. The protocol could be designed to allow for negotiation of
a common codec between two radios - start out with a simple
"universal" codec to get the communication started, and then
optionally switch to a different one.

Yes, that's what's wanted, but the current D-STAR implementation
appears to have no flexibility to do this and there are no version
fields in the frame structure so it can't be made backwards compatible.
The design ought to have had this built in, but seems not to have
considered doing it.

--

Brian Morrison

In article ,
Brian Morrison wrote:

Seems to me there's plenty of opportunity for flexibility with regards
to codecs. The protocol could be designed to allow for negotiation of
a common codec between two radios - start out with a simple
"universal" codec to get the communication started, and then
optionally switch to a different one.

Yes, that's what's wanted, but the current D-STAR implementation
appears to have no flexibility to do this and there are no version
fields in the frame structure so it can't be made backwards compatible.
The design ought to have had this built in, but seems not to have
considered doing it.

I agree, that was a bad design choice. I always like to put
field-type and field-version tags into the data structures I use...
it's a bit more work up front but saves an incredible amount of pain
further along the line!

Anybody for "Free*Star"? :-)

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

appears to have no flexibility to do this and there are no version
fields in the frame structure so it can't be made backwards compatible.
The design ought to have had this built in, but seems not to have
considered doing it.

The exact same stupidity has long crippled the advancement of the
AX.25 protocol, and the APRS protocol, and nearly every other *amateur*
designed protocol.

Worse, AX.25 was coded into law (in the USA, and elsewhere), thus
preventing any other air protocols from even having a chance because
they could not be used, or used unattended, such as a BBS.

D*Star apparently has the same problem - it's a lot like commercial P25
(or MotoTRBO), but it's a lot different too, and there's really no way
to fix that.

And how about all those surplus TETRA radios? Yah, the USA can't currently
use TETRA for commercial/industrial radio, but the rest of the world does
and there's nothing stopping USA hams from doing so.

I sure would like to see someone make an off-the-shelf digital voice ham
radio that made use of openly-available codecs, especially if they were
flashable.

AX.25's other remaining use, that of carrying tcp/ip, has also got a
real problem: the minimum IPv6 packet is bigger than the maximum AX.25
packet. Oops.
- Brian

On 24/09/2010 18:08, Brian Reay wrote:
wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.


In this case, you can always re-flash the chip containing your chosen
version of the codec.

Something very few had the capability to do back in the days when packet
was a big thing, and something you're expressely forbidden to do
(indeed, prevented from doing) with an AMBE DSP chip.