Radio Coverage FAQ

It depends on the frequency. Below 1.6 MHz the ground wave reaches hundreds of kilometres. On shortwave (1.6 to 30 MHz) the ionosphere can carry a signal around the world. From 30 MHz upwards the range is mostly the radio horizon, about 4.1 times the square root of the antenna height in metres for each antenna, changed by the terrain. Use the coverage map for your case.

On VHF, UHF and microwaves it sets the radio horizon and how much of the terrain blocks the path. On HF it sets the take-off angle at which a horizontal antenna works best. Raising an antenna is usually worth more than increasing power.

It is the farthest point two antennas can see each other over a smooth Earth, slightly beyond the geometric horizon because the atmosphere bends radio waves. Try the radio horizon calculator.

Because the terrain is not flat. Hills create shadow zones and open valleys create long arms of coverage, and a beam antenna adds lobes. See how terrain affects radio coverage.

It is the ellipsoid around the line of sight that carries most of the signal. Obstacles inside it add loss, so a good link keeps at least 60% of the first zone clear. Use the Fresnel zone calculator.

Lower frequencies diffract better around hills, so VHF usually covers valleys and shadows better than UHF, and UHF better than 2.4 GHz. In exchange, higher frequencies allow small high-gain antennas and more bandwidth.

Every 3 dB doubles or halves the signal power. Doubling the transmit power gives 3 dB; so does a 3 dB better antenna, which is often easier and cheaper than a bigger amplifier.

Yes. Choose the LoRa, ISM or Wi-Fi presets and the matching mode: the engine uses the right bandwidth, sensitivity and the terrain at 868 MHz or 2.4 GHz.

Yes, with the ionosphere, the day/night cycle, the solar flux and the Kp index. The tool shows the best band for every hour and the usable frequency window.