[App_rpt-users] AMBE question

[Mike Zingman]

Last comment on this since it is off topic for this group (but I would love
to continue it on a side channel).

When we played with this type of thing we used the DV3000 and a custom
version of the DSD code.  I grabbed audio off of the discriminator of the
radio (or from an RTL dongle), piped it into DSD, took the AMBE frames from
the decoder and fed them to the DV3000.  PCM was then fed to Allstar
through the USRP channel driver.  This gave me DMR and DStar (P25 P2 was
never tested) decode directly into a test system from the RF side.  Today,
I would use MMDVM rather then DSD as it implements a much better radio
interface and digital path.

Mike

On Thu, Oct 29, 2015 at 9:42 AM, Bryan Fields <Bryan at bryanfields.net> wrote:

> On 10/29/15 9:33 AM, Mike Zingman wrote:
> > The MBE (mbelib) code you are thinking about is both patent encumbered
> at this
> > point and only decodes AMBE frames.  It does not implement the encoder.
> I
> > have extensive experience with that code base and the audio quality as
> > compared to the chipset is not acceptable.  It is good for
> experimentation,
> > but I would never deploy a solution with it.
>
> Also in typical ham radio fashion they pissed off the original developer by
> taking his code and making it closed source.
>
> Bruce Perens K6BP is working on some legal stuff regarding the AMBE
> patents,
> but that's still a while out.  What I'd suggest is to use the TIA standards
> document and then base it off that, host it in a foreign country and make a
> script that pulls it in at compile time if the user wants it.
>
> Frankly, I'd like to see the same thing for the IRLP channel driver.
> Pulling
> that just cuz Dave got his panties in a bunch is caving to bullies.
>
> There is a channel driver for dstar that uses a dongle, written by KI4LKF.
> http://zipwww.com/a/rtpdir.weebly.com/chan_dstar.zip/chan_dstar.c.html
> I've messed with it once, it was not ready for prime time IMO, but then
> again
> there is lots of stuff we runs that's not exactly stable either.
>
>
> 73's
> --
> Bryan Fields
>
> 727-409-1194 - Voice
> 727-214-2508 - Fax
> http://bryanfields.net
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