[Xastir] revisiting aprsd

[Lee Bengston]

Off and on over the past few years there have been inquiries on this
list about both Igating and digipeating using Xastir, and generally
the response has been something to this effect: "Xastir can do some of
that, but we recommend using something else that specializes in that
function, and that fits better anyway with the Linux philosophy of
using different building blocks as opposed to one monolithic piece of
software".  In some of those conversations aprsd was brought up, and
usually someone chimed in with something like "I don't think you want
to use that".

The main problem that's been brought up with aprsd is a mangling of
mic-e packets evidently due to stripping unprintable characters when
Igating from RF to Internet.  Another issue that's been discussed is
that some versions don't support Linux ax25 sockets.

After researching a somewhat confusing array of documentation, I was
able to determine the following:

- There is evidence in the changelog for the current Debian/Ubuntu
binary package that the mic-e issue is fixed.
- There some evidence in the docs for both the Debian/Ubuntu version
and the sourceforge version that ax25 sockets are supported.
- There is no evidence in the changelog for the tarball available from
sourceforge that the mic-e issue is fixed.

- Some of the documentation submitted with the packages above along
with other docs indicate that aprsd follows the current rules for
Igating, including gating messages from IS to RF and even sending the
'courtesy posit' of the sender when applicable.

Based on the above, I decided to try the current aprsd binary in the
repositories for Debian Squeeze.  It is version 2.2.5-13-5.1 according
to the changelog.  What I found in the trial was as follows:

1) It does support ax25 networking.
2) It does seem to gate from RF to IS properly
3) However, I was disappointed to find that it did not gate a message
originated from my phone (Internet) to my D7A on RF.  Xastir,
APRSIS32, and aprx have all passed that test.

I suppose that given I am new to aprsd, perhaps I missed something in
the configuration that is preventing the gating of messages from IS to
RF.

I also noticed that if I enabled beaconing in aprsd toward the
internet, the raw packets showing up on Findu.com and aprs.fi looked
very strange.  I should have copied one while they were still there,
but they are gone now.  Beaconing on RF looked normal.

So in conclusion I can see why many people 'in the know' have landed
on javAPRSIGate as the software of choice when the OS is Linux.  It
can share a TNC with other applications like Xastir via AX25
networking, and it supports 'all the rules'.  The aprx application is
pretty good, but to the best of my knowledge it does not support the
courtesy posit when gating messages from IS to RF.  That's probably
not that big of a deal, but it would be nice if it did.

I also conclude that Xastir should beef up it's Igating functionality
simply because there are so few Linux apps that actually support it
completely.  :-)

Lee - K5DAT