Tropical band
| Surname | Frequency range |
|---|---|
| 120 meter tape | 2300-2495 / 8 kHz |
| 90 meter tape | 3200-3400 kHz |
| 60 meter tape | 4750-5060 kHz |
The tropical band is one of three frequency ranges of the limit wave between medium wave and short wave with wavelengths between approximately 60–120 m. They are defined by the ITU in the Radio Regulations VO-Funk and listed in the adjacent table. Countries in the tropical belt use these frequencies to broadcast their internal national radio programs . The frequency 5000 kHz +/- 5 kHz is used by time signal services and is therefore expressly excluded from the 60-meter band.
Outside the tropics, national radio coverage is on long wave , medium wave and ultra short wave (VHF), but this is not possible there due to strong atmospheric disturbances or a lack of infrastructure for VHF. The lower frequencies - here especially the long waves - are severely disturbed by electrical discharges during thunderstorms . In the case of short waves, the dead zone around the transmitter interferes between the end of the ground wave and the first reflection point of the sky wave on the earth's surface ( see also: Reflection on layers of the ionosphere ). VHF transmitters are only suitable locally for some metropolitan areas, but not for large-scale coverage of sparsely populated areas, since there is no complex VHF network.
The tropical band transmitters have a range of 500 to 700 kilometers during the day and are less disruptive during thunderstorms.
Similar to the medium waves, the limit waves are reflected more strongly in the ionosphere as the solar radiation subsides at dusk and at night, and radio stations from the tropics can be received at certain times under favorable conditions in Europe. The hobby of receiving radio stations from all over the world is known as "DX (en)" . The term "DX" stands for long-distance or long distance ( English Distance = Distance) and comes from the portfolio of the numerous internationally recognized radio abbreviations.
Web links
- Danish Shortwave Club International (DSWCI): Domestic Broadcasting Survey (DBS-19 from 2017 contains the 45th Tropical Bands Survey )