☰ HF Propagation menu

HF Propagation What-If Simulator

Move the sliders for solar flux, Kp and flare class to see how HF band conditions change from 160 m to 6 m, day and night.

Solar flux: 115 sfu

Kp index: 3.0

Flare class (X-ray)

Presets:

Band	Day	Night

What you can learn here

Raise the solar flux and the upper bands (15, 12, 10 and eventually 6 m) move from Poor to Good in daylight.
Raise Kp to 5 or more and conditions worsen across the board, low bands at night first: a geomagnetic storm.
Choose an M or X flare and every daytime band drops: a radio blackout on the sunlit side. Night paths are unaffected.

The simulator uses the same simplified model as the live HF band conditions page. It is a teaching tool, not a forecast: see the methodology for its limits and the guides on solar flux and Kp for the science behind it.

Data: NOAA Space Weather Prediction Center, NASA SDO. Band conditions are estimates computed by Map For HAM and are indicative only. Methodology and credits · Data feeds · Widgets