Ham Radio Weather Basics
In ham radio, “weather” can mean two different things: Earth weather (storms, lightning, damage risk) and “radio weather” (space weather) that changes propagation.
1) Terrestrial weather (safety + readiness)
- Lightning: disconnect antennas, keep feedlines grounded, and avoid touching radio gear during active storms.
- Power: keep a plan for outages (battery, generator, safe fuel storage, proper fusing).
- Go-kit mindset: pre-pack essentials (power leads, coax jumpers, headset, basic tools, printed frequency list).
- Nets: know your local severe weather / ARES / SKYWARN procedures and check-in methods.
2) Space weather (“radio weather”)
Space weather changes the ionosphere, which changes refraction/absorption and can radically alter HF—sometimes VHF (aurora) too.
- Solar flares: can cause rapid HF absorption on the dayside (minutes).
- Geomagnetic storms: can degrade polar paths, increase fading, and enable aurora (hours to days).
- Solar cycle: raises/lowers the long-term baseline for higher HF bands (weeks to years).
A-index vs K-index (quick intuition)
- Kp/K: “How disturbed is the geomagnetic field right now?” (short timescale).
- A-index: “How active has it been over a longer window?” (smoother, trend-like).
- Operator shortcut: rising Kp is often the immediate warning flag; sustained activity (A staying elevated) often means conditions may remain rough.
Operating tips that hold up
- Confirm the path: the same “conditions” can be great to one region and dead to another (latitude + local time matters).
- During absorption events: try lower HF bands, shorter paths, or wait for the sunlit side to recover.
- During storms: avoid polar routes for DX; try mid-latitude paths; expect flutter and rapid fading.
- Log what you see: build your own intuition by comparing contacts vs the Dashboard’s plots.