We have had contact with a teacher from Skåne, who have been a teacher here in Denmark and now lives in Sweden.
Introduction in Radio waves, and their propagation.
This is a picture of the earth with radio waves, the three known kinds of waves, you can see the names of the three kinds of waves in the diagram below. You can also see the distance for the HF - VHF and the UHF waves, including the frequency.
| Band | Frequency (MHz) | Wave | Type | Distance |
| HF | 3.6 | Ground wave | Reflected wave | Up to about. 500 km |
| 7.0 | Ground wave | Reflected wave | Up to about. 1000 km |
| 14.0 | Ground wave | Reflected wave | Most of the Earth Best in daylight |
| 21.0 | Ground wave | Reflected wave | Most of the world, father than Europe |
| 28.0 | Ground wave | Reflected wave | Best in daylight Can be used all over the world |
| VHF | 145.000 | Direct wave | | ca. 100 km |
| UHF | 435.000 | Direct wave | | ca. 75 km |
