Telecommunications: Transmisson of Radio Waves

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Telecommunications: Transmisson of Radio Waves
2011-05-18 21:27:52
Telecommunications Transmisson Radio Waves physics

Telecommunications: Section 4- Transmisson of Radio Waves
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  1. 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
  2. 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.
  3. what is diffraction?
    the bending of light around obstacles.
  4. 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
  5. 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
  6. 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
  7. 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