QEX Nov-Dec 2024

[KX4QC]

A fine new issue of the experimental journal included with ARRL membership.

This month, some items caught my eye:


Decoding Morse CW with a Variable-
Length Self-Synchronizing Code
Mark R. Titchener, ZL4CDE
This explains in detail not only how a self-synchronizing coder/decoder works, but also the circuitry needed to filter and delive a pure stream of code from the radio. The article is interesting, not only because it shows exactly how to perform the trick, but also how the method could be adapted to other codes, maybe Murray even. Many computer CW decoders are so much worse than an ear, but this shows how to make a good one!

Using Amateur Radio Data to Improve
Intense Sporadic-E Observations
Daniel J. Emmons & Ken Neubeck, WB2AMU
After a lousy Es season that didn't really materialize, analysis of propagation data seems ever more important to make best use of these transient opportunities.

The Design and Implementation of a Zadoff-
Chu Sequence for AGC Burst Transmission in
the Neptune Digital Communications Project
Michelle Thompson, W5NYV
Yes, Amateur radio concerns itself with microwaves too, and satellite and drone communication. The challenge is always to transmit a sufficient bitwidth to carry all necessary instructions and data to and from a flying radio. The Zadoff-Chu sequence is replacing the Walsh for rotating an 11-bit wide channel to efficiently pack data into a narrow time and frequency space. The article describes the new methods, their verification and application. Next time you see press footage of a military or exploration drone in action, and wonder how the heck can so much bidirectional data be sent, this is it!

Sorry, but the sample QEX is only for folks who summon the energy to sign in. Yes, you have to type your callsign once:

QEXnov_dec24.pdf