The story of microwave and satellite transmission is about harnessing the power of high intensity radio waves and focussing them between fixed points on Earth - or in Space. We may think that these are 'Space Age' technologies but their story starts well over 70 years ago.
Origins of microwave
In a sense, microwave and satellite links go right back to one of the ancient principles of primitive signal beacons - that you need a line of sight between two points. The difference is now the two points can be thousands of miles apart - and not even on the surface ...
Why use a dish? : high beam radiowaves
Why does a car headlamp have a reflector behind the bulb? It is to trap all the light energy from the bulb and focus it out forward where it is needed.
In the same way, radio aerials work most efficiently when arranged to direct or 'focus' the radio energy in the direction required.
The shape of the reflector depends on the frequency or wavelength of the radio signal in use - at VHF and UHF frequencies the reflector is usually made out of a metal rod or 'elements' pointed in a specific direction, but at the shorter microwave wavelengths (which behave more like light), a parabolic reflector, like a satellite dish, is more efficient.
The dishes are used to receive satellite television at home, as well as at satellite earth stations and at the Jodrell Bank radio telescope. The dish itself focuses the radio waves it receives onto the active antenna element at the focal point in the centre - just like a car headlamp.
The need for microwave : shifting the volume
As more lines were installed after the First World War, the volume of calls on the British telephone network started to increase at a dramatic rate.
Routing all these calls along the trunk network meant providing bigger and bigger cables to provide the capacity that was needed.
But extending the trunk network over wild countryside or across water posed a problem - how to do so quickly and without having to lay large cables, which were unwieldy and expensive.
Microwave provided a possible answer - a wireless link that would use focused high intensity point-to-point beams to carry high volumes of traffic simultaneously.
As more lines were installed after the First World War, the volume of calls on the British telephone network started to increase at a dramatic rate.
Routing all these calls along the trunk network meant providing bigger and bigger cables to provide the capacity that was needed.
But extending the trunk network over wild countryside or across water posed a problem - how to do so quickly and without having to lay large cables, which were unwieldy and expensive.
Microwave provided a possible answer - a wireless link that would use focused high intensity point-to-point beams to carry high volumes of traffic simultaneously.
The first satellites
The theory of satellites was simple enough - shoot something out into space at the right speed and on the correct trajectory and it will stay up there, orbiting Earth, for years - if not forever. And if that orbit is just the right distance out in space the satellite will keep pace with the rotation of the Earth - remaining on station out there in the skies. Theory was one thing - but achieving the vision was not so simple.
Pioneer satellites (1957) : 'they're up there...'
Early in October 1957 communications stations started picking up a regular beeping noise coming from space.
The signals were coming from Russia's Sputnik 1, the world's first man-made satellite. The launch of Sputnik caused a panic in Washington, as the USA realised how far it had fallen behind in the space race. The worries deepened three months later, when a Vanguard rocket with America's first satellite exploded two seconds after ignition.
It was January 1958 before a Jupiter rocket successfully launched Explorer 1, the first American satellite.
Early in October 1957 communications stations started picking up a regular beeping noise coming from space.
The signals were coming from Russia's Sputnik 1, the world's first man-made satellite. The launch of Sputnik caused a panic in Washington, as the USA realised how far it had fallen behind in the space race. The worries deepened three months later, when a Vanguard rocket with America's first satellite exploded two seconds after ignition.
It was January 1958 before a Jupiter rocket successfully launched Explorer 1, the first American satellite.
NASA's Syncom programme (1963) : proving the geosynchronous concept
In July 1963 the Hughes Aircraft Corporation launched the experimental Syncom 2 for NASA, the world's first geosynchronous communications satellite. Its earlier sister, Syncom 1, had been blown up on launch earlier that year, but version two was a huge success. It carried the first live two-way satellite call between heads of state when President John F. Kennedy in Washington, D.C., telephoned Nigerian Prime Minister Abubaker Balewa in Africa.
The third Syncom satellite transmitted live television coverage of the 1964 Olympic Games from Tokyo. Syncom blazed the trail for the new generation of communications satellites in geosynchronous orbit.
In July 1963 the Hughes Aircraft Corporation launched the experimental Syncom 2 for NASA, the world's first geosynchronous communications satellite. Its earlier sister, Syncom 1, had been blown up on launch earlier that year, but version two was a huge success. It carried the first live two-way satellite call between heads of state when President John F. Kennedy in Washington, D.C., telephoned Nigerian Prime Minister Abubaker Balewa in Africa.
The third Syncom satellite transmitted live television coverage of the 1964 Olympic Games from Tokyo. Syncom blazed the trail for the new generation of communications satellites in geosynchronous orbit.
