Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3 MHz. Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band or hectometer wave as the wavelengths range from ten to one hectometers (1,000 to 100 m). Frequencies immediately below MF are denoted Low-frequency (LF), and the next higher frequencies are known as High-frequency (HF).
Non-directional navigational r...
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Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3 MHz. Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band or hectometer wave as the wavelengths range from ten to one hectometers (1,000 to 100 m). Frequencies immediately below MF are denoted Low-frequency (LF), and the next higher frequencies are known as High-frequency (HF).
Non-directional navigational radio beacons (NDBs) for maritime and aircraft navigation occupy a band from 190 to 435 kHz, which overlaps from the LF into the bottom part of the MF band.
500 kHz was for many years the Maritime distress and emergency frequency, and there are more NDBs between 510 and 530 kHz. Navtex, which is part of the current Global Maritime Distress Safety System occupies 518 kHz and 490 kHz for important digital text broadcasts. In recent years, some limited amateur radio operation has also been allowed in the region of 500 kHz in the USA, UK, Germany...
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