Cheap (but good...) 9600 baud packet radio
Packet radio is stuck. 18 years after the developers of the TNC-1 said that 1200 baud was only temporary, and that packet radio needed much higher speed to be truly useful, the vast majority of packet operations are still at 1200 baud. A few folks have done work at higher speeds, but for various reasons those efforts have never made it to the mass market.
Amateur radio use of TCP/IP is also stuck. While TCP/IP has become the most widely used data protocol in the world -- if you're on the Internet, you use TCP/IP -- its use in ham packet networks has been stagnant or worse over the last several years.
If you're interested, I've put together some thoughts about Why we are stuck at 1200 baud. This paper is still very much a work in progress.
These pages document a project that ties together some bits of technology, some admittedly ancient and some newer, to move packet radio into a new model, with a new user interface. The idea is to provide users with a low cost, easy to configure 9600 baud packet radio system that enables an amateur radio version of the Web, using standard Windows-based tools like web browsers and email clients.
The building blocks are:
An inexpensive 9600 baud data radio. One commercially available version
is the TEKK TS-900. Our group found itself owning a couple of boxes
full of used Maxon data radios originally designed for 1200 baud work,
so being cheap, we're converting those for 9600 baud. The mod is quite
simple, and may be applicable to many crystal-controlled handy-talkies of
The Baycom PicPar 9600 baud modem, sold
in the US by Tigertronics. This
is a little dongle that hangs on the parallel port of an AT or faster PC and,
with the proper software (which is available for DOS, Windows, and Linux),
provides the equivalent of a 9600 baud TNC. At about $100, it's the lowest
cost 9600 baud packet device available, and it seems to perform well. The
PicPar is supported by (at least) DOS, Windows95/98/NT, and Linux.
The SV2AGW Packet Engine is the
software of choice for end-users in our project. This set of programs
provides a Windows95/98/NT interface to several TNC-like devices, including
the Baycom modems. Not only does this software provide basic packet radio
tools, it has a TCP/IP interface that is easy to configure and provides
good performance. This is the key to providing an Internet-like interface
for end users; the SV2AGW software lets the user's interface be Netscape
or any other Windows-based network program.
- Finally, the Linux Operating System provides the servers that our Windows-based TCP/IP systems want to talk to. Linux has built-in support for AX.25, and makes it possible to provide all the Internet services we've come to depend on, via radio links. I have put some information on Configuring Linux AX.25 at my web site.