Subj : Re: VARA Modem
To   : echicken
From : Vk3jed
Date : Wed Feb 23 2022 12:49:00

-=> On 02-21-22 06:05, echicken wrote to Vk3jed <=-

 Vk> Apparently it works quite well, but it is proprietary, so you're stuck

 ec> Yuck. I remember seeing some other data mode like this recently, though
 ec> I believe its creator stated some intent to share the details later on.
 ec> Seems like a sure way to prevent adoption of your mode.

Yeah, one wonders.  Open source not only allows multiple implementations to
flourish, but it also can attract a community of developers, testers, users and
others interested in the project.  The M17 project is a perfect example of a
community that's arisen from open source in ham radio.

 Vk> kinda like the AMBE nastiness in many DV modes, where you have to have a
 Vk> chip to (legally) process the audio.

 ec> Yep, and most DV modes have not seen very wide adoption, except DMR in
 ec> the past decade thanks to cheap HTs with said codec on board.

DMR and to a lesser extent, Fusion (the FT-70 is reasonably priced too).  Will
be interesting to see what happens with M17, once suitable radios become
available.  M17 is a 100% open source DV mode.  It uses the Codec2 vocoder for
its speech compression.

 ec> I suppose it could still be a replacement, but one would have to
 ec> coordinate with every other station that normally connects to theirs.
 ec> That seems ... unlikely.

Unloess you can run multimode somehow.

 Vk> You can always use Direwolf if you want a software modem/TNC that's

 ec> I've used it briefly and have heard great things, but I have no real
 ec> need for it at the moment.

Direwolf is excellent.

 Vk> compatibile with legacy systems - software implementation with better
 Vk> performance than hardware - there's a writeup somewhere on how Direwolf

 ec> Performance as in being able to decode weaker signals? I'll have to
 ec> look for some info on that.

Direwold is more tolerant of maladjusted radios.  It actually uses multiple
modems in parallel on receive to process signals with different levels of twist
between the two tomes and takes the best decoded output.  Direwold also has an
extension to the AX.25 protocol that allows lower BER (and more decoded frams)
at low SNR.  This extension is backwards compatible with standard AX.25, and
the extra error correction is ignored by standard TNCs.  This is because the
extension is a wrapper around the standard frame that contains the extra FEC,
and a standard TNC simply sees the standard frame within.

The more I learn about Direwolf, the more I like it.


.... DOS never says EXCELLENT command or filename...
--- MultiMail/Win v0.52
 þ Synchronet þ Freeway BBS, Bendigo Australia.  freeway.apana.org.au

.