IAN LANG ELECTRONICS

Aerial or Antenna?

These two terms are now synonymous but for the pedantic amongst us there is a difference. The term antenna used to be applied to a solid vertical pole, and the reason for this is that Marconi's earlier experiments used a metal cross-pole from a tent as the radiator, which in Italian was known as the antenna centrale. A piece of wire slung between two poles was hanging in the air, and so became known as an aerial wire. It really does not matter which term you use, people will know what you mean.

Hereto we have not discussed wavelength, it is simply the speed of light divided by the carrier frequency, and so for , let us say Talksport, on 1053 kHz the wavelength would be 285 metres, for Radio 5 on 693 kHz 433 metres. A longer wave can travel further round the curvature of the Earth and that's where AM scores over FM (remember because of the large bandwidth you cannot transmit FM on lower frequencies) in that you do not need as many transmitting stations or repeaters.