Welcome!
Thank you. I would like to work on the soundmodem package. I do understand that debian is all about packaging and distribution and not so much on working on the upstream.
However, since almost all upstream links are looking defunct and I have not been able to contact Thomas Sailer (the original author) and I want to contribute changes to the source code as well I am seeking for advice or suggestions of how to proceed.
Re: Roland OE1RSA
Thank you. I would like to work on the soundmodem package. I do understand >> that debian is all about packaging and distribution and not so much onHi Roland,
working on the upstream.
However, since almost all upstream links are looking defunct and I have not >> been able to contact Thomas Sailer (the original author) and I want to
contribute changes to the source code as well I am seeking for advice or
suggestions of how to proceed.
afaict the modem to use these days is direwolf. Is there anything that soundmodem does that direwolf doesn't do?
Generally you can of course also use salsa.debian.org to host
upstream, it might be more sensible to use some "mainstream" git
hoster like github or gitlab if you plan to become the new soundmodem upstream. That way chances of getting other people's contributions
might be better.
(Some googling later) The current upstream repo for soundmodem is
actually on gitlab, and the last commit by Thomas was 1 hour ago:
https://gitlab.com/tsailer/soundmodem
(The hast activity before that was in 2016, though.)
Christoph
afaict the modem to use these days is direwolf. Is there anything that soundmodem does that direwolf doesn't do?
(Some googling later) The current upstream repo for soundmodem is
actually on gitlab, and the last commit by Thomas was 1 hour ago:
https://gitlab.com/tsailer/soundmodem
(The hast activity before that was in 2016, though.)
Yes, I am aware of this fact. Indeed the direwolf modem for sure is a
very solid implementation with a vivid user community. My perception, however, is that direwolf is focused on APRS and comes with its own implementation of an ax25 stack.
What I like about the soundmodem is its tight integration with the
linux ax25 kernel stack and the fact that it is capable of multimode.
There are other reasons as well that make the codebase interesting to
me, but about that later, if you really like.
Direwolf can be directly connected to the Linux AX.25 stack either via
it's PTS pseudo-serial interface or it's TCP-KISS interface and socat.
Next up, yes, soundmodem does offer the ability to send AX.25 packets
over at least one alternative mode but in my experience, that one mode
didn't perform very well and never gained any adoption.
Direwolf offers
multiple modes (AFSK, FSK, PSK, QPSK, IL2P, etc) as well as FX.25
support be it for speed, robustness, etc.
Finally, if you run various
packet decode tests, you'll see that Thomas Sailers's soundmodem gets
about a 60-65% decode rate where as Direwolf, UZ7HO's soundmodem, and
even some hardware TNCs get in upwards of 95%:
https://raw.githubusercontent.com/wb2osz/direwolf/master/doc/WA8LMF-TNC-Test-CD-Results.pdf
Unfortunately kissattach is not very systemd friendly because it
does not store its pid into a file, so it can be controlled.
Yes this could be fixed by fixing kissattach, and yes the issue can be
worked around. "soundmodem" on the other hand does not need kissatach
because it uses the kernel mkiss interface.
...
Perhaps we do not understand the same thing when speaking about modes?
What I mean is that you can set up, say 1200Bd and 9600Bd on the same
radio link at the same time (well almost), i.e. you can work two
different stations each connected at its speed of the same radio
link. To my knowledge this is a feature that is planned for direwolf,
but not available today, correct?
Yes, thank you, I know all these facts and I have successfully tried
them out. The kissattach program, however, is needed to connect the
ptty. Unfortunately kissattach is not very systemd friendly because it
does not store its pid into a file, so it can be controlled. Yes this
could be fixed by fixing kissattach, and yes the issue can be worked
around. "soundmodem" on the other hand does not need kissatach because
it uses the kernel mkiss interface.
What I mean is that you can set up, say 1200Bd and 9600Bd on the same
radio link at the same time (well almost), i.e. you can work two
different stations each connected at its speed of the same radio link.
To my knowledge this is a feature that is planned for direwolf, but not available today, correct?
It's been a long time since I've used Thomas Sailer's soundmodem and I
don't remember if it supported such a configuration but I would be
surprised if it did.
Even if it does, it's decode performance is so low
(especially on 9600bps FSK), why would it really matter?
Btw.. if you're looking for alternatives to Direwolf that are actively maintained and have good to excellent decode rates, you might want to
check out John Weisman's soundmodem which is based on Andy Kopanchuk
UZ7HO's Windows soundmodem:
On 09.11.21 at 16:38 wrote Basil Gunn:
Example of how to use kissattach with systemd. Kissattach is called from
a script ax25-upd
https://github.com/nwdigitalradio/n7nix/blob/master/systemd/ax25/ax25-upd
Thank you for the pointer to these great scripts! After a first look
into them a question pops up: How is the kissatach killed on tear
down?
I cannot see the line where this is done. Would you please so kind and explain it to me?
Example of how to use kissattach with systemd. Kissattach is called from
a script ax25-upd
https://github.com/nwdigitalradio/n7nix/blob/master/systemd/ax25/ax25-upd
Even if it does, it's decode performance is so low
(especially on 9600bps FSK), why would it really matter?
I know all this and I already started working on the "problem".
check out John Weisman's soundmodem which is based on Andy Kopanchuk
UZ7HO's Windows soundmodem:
This might be a good modem, but using a modem on the wine emulator under linux definitively is not something I want to do. So, thank you, but no.
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