Radio Communications: FT8 Monitoring Update

 

A while back, I discussed how I had been monitoring FT8 ham radio signals. FT8 is a digital ham radio mode that packs short, structured messages (callsigns, grid squares, signal reports) into 15-second time slots and uses heavy forward-error-correction plus synchronized clocks to decode signals many decibels below what the human ear or older modes could ever pull out of the noise.

It's fascinating, and the screen capture above is from an app that I built to log and map FT8 signals that I receive here in Central Texas from Hams who are engaging in this form of communication worldwide. The furthest signal I have detected is Rodriguez Island, some 11,000 miles away!

Its Creator is an Astrophysicist (and Nobel Laureate). FT8 was co-created by Dr. Joe Taylor (K1JT). In the professional scientific world, Dr. Taylor is a high-profile radio astronomer. In 1993, he won the Nobel Prize in Physics for discovering the first binary pulsar (a pair of dense neutron stars orbiting each other). That discovery provided the first indirect evidence for the existence of gravitational waves - a monumental breakthrough in astrophysics.

Standard FT8 relies on bouncing radio waves off Earth's ionosphere to reach the other side of the planet. The ionosphere is entirely dictated by astronomy - specifically, Solar Physics:

•  - Solar Flares & Sunspots: Energy from the Sun charges (ionizes) the upper atmosphere. When the Sun is active, high-frequency (HF) bands open up globally; when it's quiet, those paths disappear.
•  - Space Weather Tracking: Because millions of automated FT8 signals are sent around the globe every day, scientists use aggregate FT8 data (via networks like PSK Reporter) as a real-time, global sensor array to map how the Sun's radiation impacts Earth's upper atmosphere during solar storms.

The graphic below explains the concept fairly well:

Anyway, good fun and it's been interesting to watch those signals come in as various factors affect our atmosphere. Easy to get into as well. I'll put a post together about how I do it sometime soon!