Medium Wave

From Freeradio

Medium Wave (MW) refers to the band between 522 and 1611 kHz. Medium Wave transmissions use Amplitude Modulation (AM), with 9kHz bandwidth.

The main advantage of Medium Wave (over FM and Short Wave) is that high power signals can reach large distances - several hundreds of miles - during daytime hours with a steady signal ie little fading. After dark, the range of MW signals can be thousands of miles, but reception quality deteriorates more locally due to fading and also interference from more distant transmitters.

Another advantage of Medium Wave over FM is that MW signals can penetrate valleys in hilly areas better than VHF signals.

Medium Wave has generally been used as the main frequency for Offshore radio stations, and has been widely used by the Eire super pirates.

The use of MW by UK land based pirates, however, has been more sparse - VHF FM tending to be the preferred band for various reasons.

Possibly the main reason is the disadvantages of MW - the AM signals on MW are more prone to noise and interference than FM signals, the audio quality on MW is poorer than that on FM due to the lower audio bandwidth (4.5 kHz as opposed to 15 kHz for FM), and FM stereo receivers (and transmitters) are much more widespread than AM stereo receivers (almost non-existant in Europe).

In addition, for low power transmission in a relatively flat area, the use of MW gives little if any increased range over that of FM. Also, MW antennas need to be larger (and more visible!) than VHF FM antennas.

Nonetheless, a number of UK land based pirates have used Medium Wave, sometimes in addition to FM and even Short Wave.

UK Land based pirates which have used MW

Radio Jackie (London)

Radio Mersey Waves (Liverpool)

Power FM from Derby, in the late 1980s

Sunshine Radio (Ludlow)

UK Radio (Black Country)