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  • Rights: The University of Waikato Te Whare Wānanga o Waikato
    Published 27 March 2013 Referencing Hub media
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    Kelvin Barnsdale shows us a simple homemade aerial that receives signals from an amateur radio satellite1. Kelvin2 uses his laptop to view the satellite images.

    Point of interest
    The New Zealand Association of Radio Transmitters has branches all over the country. Visit their website to learn more about amateur radio.

    Transcript

    Kelvin Barnsdale

    Anybody can receive a satellite signal with a simple aerial and a receiver like this. The aerial here is something I made using just wood and aluminium. There’s two frequencies this aerial is used for – the longer wavelength3 is the longer rods here, which is the signals that go up to the satellite, and the signals that come down from the satellite use the shorter rods cause they’re a shorter wavelength or a higher frequency4. The satellite we’re looking at today is an amateur radio satellite that has a camera on board that sends pictures from the satellite down to us, and we can decode those pictures on a laptop.

    And this satellite sends the information, the picture from that camera to us, and so we can receive the pictures on the ground and get pictures of whatever’s underneath the satellite at the time – so I can do that. If I connect the computer to this receiver and then I start the software on the computer, and then I point the aerial at the satellite, we should get a picture coming through and it looks like the satellite’s over the north of New Zealand at the moment, and we’re getting a picture of Northland and down into Auckland area.

    1. satellite: Any object that orbits around another object.
    2. Kelvin: 1. Kelvin temperature scale – An SI (international system of units) temperature scale used by scientists. It goes up in the same steps as the Celsius scale, but starts at absolute zero (-273.15 °C).
      2. kelvin – A unit of temperature named after William Thomson (1824–1907), known as Lord Kelvin. It is equivalent in size to a degree Celsius and forms the basis of the Kelvin temperature scale. The starting point of this scale, absolute zero, is the lowest temperature that can be achieved.
    3. wavelength: The distance between two successive points of a wave (from one peak or crest of a wave and the next peak or crest). Usually refers to an electromagnetic wave, measured in nanometres (nm).
    4. frequency: 1. How often something occurs within a specified time. 2. The number of waves per second that pass a given point or the number of waves produced per second by a source.
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      satellite

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    2. Any object that orbits around another object.

      frequency

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    4. 1. How often something occurs within a specified time.

      2. The number of waves per second that pass a given point or the number of waves produced per second by a source.

      Kelvin

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    6. 1. Kelvin temperature scale – An SI (international system of units) temperature scale used by scientists. It goes up in the same steps as the Celsius scale, but starts at absolute zero (-273.15 °C).
      2. kelvin – A unit of temperature named after William Thomson (1824–1907), known as Lord Kelvin. It is equivalent in size to a degree Celsius and forms the basis of the Kelvin temperature scale. The starting point of this scale, absolute zero, is the lowest temperature that can be achieved.

      wavelength

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    8. The distance between two successive points of a wave (from one peak or crest of a wave and the next peak or crest). Usually refers to an electromagnetic wave, measured in nanometres (nm).