Talks & Publications

Writing and speaking on amateur radio, digital modes, and the theory behind them. I’m particularly interested in explaining why things work rather than only how, and in finding the parallels between radio and other technical fields.

If you’d like me to speak to your club or group, contact details are in the footer.

Publications

Understanding FT8 through DNA-sequencing parallels

RadCom, Radio Society of Great Britain, May 2026

FT8 routinely decodes stations at signal-to-noise ratios as low as −24 dB, on bands that sound completely dead. My day job is with DNA sequencing systems, which face a strikingly similar problem: reading billions of individually minute, noise-swamped molecular signals at better than 99.9% accuracy. The two fields arrived independently at the same engineering answers, namely structured message formats, precise timing synchronisation, strong error correction, and quality metrics.

The article uses those parallels to explain how FT8 achieves such extraordinary weak-signal performance. No molecular biology or advanced mathematics required, just the engineering trade-offs that make information transfer possible in high-noise environments.

Seeing signals: I and Q from first principles

RadCom, Radio Society of Great Britain, September 2026

IQ data sits at the heart of every modern software-defined radio, yet it’s usually presented as an equation rather than something you can picture. This article builds I and Q up from first principles and with minimal mathematics: why a single measurement of a wave is ambiguous, how a pair of quadrature measurements resolves that ambiguity completely, and what the resulting IQ plot actually shows you for real signals, from a bare carrier and CW, through AM, FM and SSB, to the digital modes.

A reader question about the article, on whether ASK, FSK and PSK can be combined, is answered in Can you combine ASK, FSK and PSK?.

Resources referenced in the article:

Setup for IQ visualisation and digital signal processing
sdrconnect-iq-visualiser, my SDRconnect IQ visualisation plugin
sdrplay-gnuradio-examples, my GNU Radio flow graphs for SDRplay devices
SDRplay · GNU Radio · Radioconda

Invited talks

Understanding FT8 through DNA-sequencing parallels

RSGB Convention 2026, Saturday 10 October 2026, 10.30 to 11.15 Kents Hill Conference Centre, Milton Keynes

FT8 routinely decodes stations at around −20 dB SNR on bands that sound completely dead. DNA sequencing faces the same problem in a different domain: reading billions of tiny, noise-swamped molecular signals at better than 99.9% accuracy. Both fields arrived independently at the same engineering answers, namely structured messages, precise timing, strong error correction, and quality metrics. This session uses those parallels to explain how FT8 achieves its weak-signal performance. No biology or advanced mathematics required. Based on the May 2026 RadCom article of the same title.

RSGB Convention programme and speakers

Making the invisible visible: understanding your SDR through IQ visualisation

RSGB Convention 2026, Sunday 11 October 2026, 10.45 to 11.30 Kents Hill Conference Centre, Milton Keynes

IQ data sits at the heart of every modern SDR, yet it’s usually presented as an equation rather than something you can picture. This session builds I and Q up visually and with minimal mathematics: why a single measurement of a wave is ambiguous, how quadrature resolves it, and what real signals look like on an IQ plot. Examples run from a bare carrier through CW, AM, FM and SSB to digital modes like RTTY, FT8, PSK and QAM.

RSGB Convention programme and speakers
Signal Explorer, which carries the same material

Making the invisible visible: understanding SDR through IQ visualisation

Cambridge and District Amateur Radio Club (CDARC), 8 May 2026

The first outing of the IQ talk, given to my home club. Starting from the idea that a wave is the shadow of something rotating, it builds up to I and Q, then works through what noise, carriers, CW, AM, FM, SSB and the digital modes each look like on an IQ plot, with a live Raspberry Pi and RTL-SDR showing real signals off air.

Raspberry Pi SDR, the demonstration device

Tools

Two interactive tools that go alongside the writing and the talks. Both are free, run entirely in your browser, and are written and maintained by me.

Signal Explorer

A radio simulator you can watch and hear. It covers the analogue and digital modes, and carries every panel of Figures 4, 5 and 6 from Seeing signals: I and Q from first principles under its own number. Currently in beta.

Signal Explorer

Bench Test

Interactive pages for the technical part of the amateur radio syllabus. Each page turns the circuits from a syllabus group into working instruments: move a component value and the browser solves the circuit again, so the readings, the waveforms and the working underneath all update together. The pages are free, run entirely in the browser, and work offline once loaded. They are meant to sit alongside a course and the books rather than replace them.

A work in progress, with further syllabus groups still to come.

Bench Test, at bench.g0lft.org