Shortwave
Type your ZIP. The set works out what the ionosphere is bouncing into your neighborhood right now, where it came from, and where you can hear it for real.
Chart · where it comes from
Log · what’s coming in
| kHz | Signal | Station · from · path | Language |
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Why shortwave gets out
Radio does not bounce off the sky at every frequency. Below the window, the daytime D layer absorbs a signal before it ever reaches the reflector. Above the window, the F layer still bends the signal, just not far enough, and it leaves for space. Between roughly 3 and 30 MHz — and only there — the sky both lets a signal up and hands it back, over and over, until a few hundred kilowatts have crossed an ocean. Move the slider and watch the window open and close.
The amber band is the slice the sky is returning right now — not a fixed allocation, but whatever the ionosphere happens to be doing. Switch to NIGHT and watch it slide down.
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How the set decides what you hear
Every broadcast on the log is real: the schedule is the EiBi shortwave database, refreshed weekly, with each transmitter’s actual site and coordinates. Solar flux and the Kp index come from NOAA’s Space Weather Prediction Center every hour.
For each broadcast on the air at the chosen minute, the set traces the great-circle path from the transmitter to you, splits it into ionospheric hops of up to about 3,500 km, and checks each bounce point: is the sun up there (daytime D-layer absorption eats the low bands), is the F-layer dense enough to reflect that frequency (the MUF), does the path cross the auroral zone, and is the transmitter’s antenna pointed your way. The tuning meter is the result. It is a model, not a measurement, so treat it like a good propagation forecast, not a promise.