Unnamed project
A hardware tool the author built ("ages ago") to monitor mains power frequency with a resolution of some microseconds, originally intended to test whether power-grid phase jitter correlates with space weather — essentially using the mains power system as a sort of radio telescope. The space-weather correlation never worked (partly due to limited time), though the author could see interesting effects such as generators spinning up to maintain grid frequency. The author believes better code optimization and optocoupler choice could push resolution down to hundreds of nanoseconds, and plans to open source the hardware when done.
What it addresses
The original goal of correlating mains phase jitter with space weather was never achieved (the author had little time to try); improving resolution from microseconds toward hundreds of nanoseconds requires better optimization and optocoupler choice.
Shared over time
Each entry reflects what was shared on that date. Details and invitations may have changed since then.
Unnamed project
A hardware tool the author built ("ages ago") to monitor mains power frequency with a resolution of some microseconds, originally intended to test whether power-grid phase jitter correlates with space weather — essentially using the mains power system as a sort of radio telescope. The space-weather correlation never worked (partly due to limited time), though the author could see interesting effects such as generators spinning up to maintain grid frequency. The author believes better code optimization and optocoupler choice could push resolution down to hundreds of nanoseconds, and plans to open source the hardware when done.
Problem: The original goal of correlating mains phase jitter with space weather was never achieved (the author had little time to try); improving resolution from microseconds toward hundreds of nanoseconds requires better optimization and optocoupler choice.
Audience: Self-described curious tinkerer ('I am not an astronomer, just some random fellow that investigates things at depth'); presumably of interest to other hobbyists and amateur scientists interested in grid monitoring and space weather
Posted by @Saigonautica · Builder identity supported: @Saigonautica · Original comment ↗
From the discussion
A commenter who did something similar years ago offers practical guidance for the measurement approach: most optocouplers only switch at ~100 kHz at best, high-precision instrumentation uses a stable comparator to sync AC zero-crossing events and time the roll-off gap over several cycles, line filters and clip-on chokes can add a digit of precision on older equipment, and hardware beyond 12-bit precision or 60 MHz SDR bandwidth likely faces export restrictions.
“High precision instrumentation just uses a stable comparator to sync the AC line Zero crossing events, and times the sharp roll-off gap over several cycles to estimate the center transition event.”
@Joel_Mckay · Nov 9, 2026 · Original reply ↗
A commenter counters the zero-crossing-comparator advice, stating that actual high-precision instrumentation band-limits the signal before atan2() rather than using a comparator that samples noise from DC to daylight.
“Actual high-precision instrumentation band-limits the signal on its way to atan2(), rather than using a comparator that samples the noise from DC to daylight.”
@CamperBob2 · Nov 9, 2026 · Original reply ↗
Another commenter reacts positively to the idea and asks whether the builder is familiar with magnetotelluric geophysical surveys, a related geophysics technique.
“This is a neat idea. Are you familiar with Magnetotelluric geophysical surveys?”
@thirtygeo · Nov 9, 2026 · Original reply ↗