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.
- “The author leads us through the process of fixing several known problems with
AX.25 modems, leading to a new software modem.”
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.
- Examining Ambiguities in the Automatic Packet Reporting System.pdf
- Notable quote: “It has been jokingly said that once a digipeater goes on the air, none of its settings will be changed until either the digipeater or its owner dies”
RF circuit ideas
- RF power detector by LA9XNA. Might be useful to help detect and react to an runaway transmitter TOT plus provide a measurement of interest to system housekeeping.
- Simple Digital Power Meter by G8KBB.
- ASME Y14.44-2008 – Reference Designations for Electrical and Electronics Parts and Equipment