tinychaseLab · WSPR against three dexes
Do Volcanic Eruptions Impact WSPR Propagation?
WSPR is a global propagation sensor: 200 million beacon receptions a month, each a measured signal-to-noise ratio on a known path. Big eruptions launch pressure waves that reach the ionosphere, which is what shortwave radio bounces off. So a volcano ought to be visible in the radio. It is not. A solar flare, run through the same code, is unmissable.
First, what a real ionospheric disturbance looks like
The X9.0 solar flare of 3 October 2024, peaking at 12:08 UTC. A flare ionises the daylit half of the planet and leaves the night half alone, so the nightside is a control inside the same minutes. Each bin is divided by the same bin on four control days, which cancels the band-hopping schedule WSPR stations share, and then by the hour before the flare.
The eruption, in the wave's own frame
Every spot on Earth is placed at the lag between when it was heard and when the eruption's pressure wave is predicted to reach its path midpoint. A real effect lines up at lag zero at every longitude and local time; no confounder can follow a front moving at 310 m/s. The frame is rebuilt at eleven wave speeds: a real wave must peak at the physical one.
The one thing that looked like a signal
Sign-blind frequency scatter rose about 1.1 Hz near the predicted arrival, and the rise peaked at the physically right speed. That is the shape a real wave makes, so it gets the hard test: is it localized at the arrival?
What would have been detected
Two standard deviations of the control spread, in the same window and frame. An effect larger than this would have shown.