Telecommunications: Transmisson of Radio Waves
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what are curved receiver dishes used for?
- to increase the strength of a received signal from a satellite or other source.
- The curved shape of the reflector collects the signal over a large area and brings it to a focus.
- The detector is placed at the focus so that it receives a strong signal
what are curved transmitter dishes user for?
- used on certain transmitters to transmit a strong, parallel beam of signal.
- In a dish transmitter the signal source is placed at the focus and the curved shape of the reflector produces a parallel beam of signal.
what is diffraction?
the bending of light around obstacles.
what advantage does radio waves have over TV waves?
- Radio waves have a longer wavelength than television waves and therefore can bend round obstacles such as hills, buildings or trees more easily.
- Therefore radio reception is better than television reception in such areas
what does the time taken for a satellite to complete one orbit of the Earth depend on?
- its height above the Earth,
- the higher the orbit of the satellite the longer it will take to orbit
what is a geostationary satellite?
- they take 24hrs to orbit the Earth
- this is the same time that Earth takes to complete one rotation and so the satellite always remain above the same point on the Earth's surface
what is a Ground Station?
- They send signals to the satellite using a curved dish transmitter to transmit a strong signal.
- At the satellite the signal is collected by a curved dish receiver, then amplified and finally retransmitted back to the ground using another curved dish transmitter
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