This page is just a list of references found helpful in the pursuit of “packet perfection” organized broadly by category.

Bell 202 – Hardware vs. Software vs. DSP

“A High-Performance Sound-Card AX.25 Modem”

This 2012 QEX articles shows the improvements possible to detect the two Bel 202 tones even when they are of unequal amplitudes due to radio de- and pre-emphasis issues.

  • QEX-JulAug-2012.pdf
  • “The author leads us through the process of fixing several known problems with
    AX.25 modems, leading to a new software modem.”

Dire Wolf

A set of software components replicating and improving the decode of Bell 202 signals with an APRS focus, but should be applicable to general purpose packet… I hope.

  • The PDF documentation is a great resource, but GitHub sure makes it more difficult to download and read on your own computer than need be.


“Examining Ambiguities in the Automatic Packet Reporting System”

This 2014 master’s thesis takes a good, long, deep, look at just about every piece of the APRS puzzle including an instructive view of the various network layers.

RF circuit ideas

Industry References

  • ASME Y14.44-2008Reference Designations for Electrical and Electronics Parts and Equipment