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Thread: Spectrum

  1. #1 Spectrum 
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    Ok i know that it is possible to see the visible part of the spectrum and the infrared part of the spectrum with something like a camera with nightvision but is there any way to see radio waves with something like a camera?

    also i have a few more questions is the spectrum made entirely up of light?
    if light cant pass throught a solid object such a wall then how can radio waves?


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  3. #2  
    Forum Isotope Zelos's Avatar
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    camera and see it? think it should be possible

    why light cant? guess its the same reason why visible passes throu glass, while infrared dong, it has the wrong frequens while radio often has the right to pass some, but then it can also be that both passes but we simply see normal light


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  4. #3  
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    if light cant pass throught a solid object such a wall then how can radio waves?

    Radio waves pass through walls yes to an extent - they are attenuated (absorbed if you like) this 'passing through' is because they have a magnetic property - hence when they 'cut' the conductor of your antenna they induce a small voltage, - if your wall is made of steel they will not go through it (though they may be re-radiated which is subtley different). Also water, mountains and most other obstacles/substances will affect the passage of these waves.

    so as long as your wall is 'thin' they appear to travel through.

    As for 'light' that is the human definition for the phenomina of sight, which just happens to occupy a small part (less than an octave) of a spectrum that includes all 'non-zero' frequencies.

    Finally welcome to this forum and please do not be put off by replies which you may receive from time to time which are clearly authored
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  5. #4 Thx :) 
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    Hey well thanks for the info. And a great forum i might add. :-D
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  6. #5  
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    Photographing radio waves? The idea sounds really cool, and I guess you can plot the radiowaves you recieve on a graph. But it probably wouldnt look really spectacular. If you make a normal photo of your living room you record the differences in wavelength (=colour) of the radiation from different objects and places. But a 'radio photo' of your living room would give a uniform mess, because at any place you record the same radio waves (otherwise your radio would only work at some places).
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  7. #6  
    Universal Mind John Galt's Avatar
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    Broken, you might find this link useful. It includes an illustration of the spectrum, with details on frequency, wavelength and energy per photon.
    http://www.lbl.gov/MicroWorlds/ALSTo...c/EMSpec2.html
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  8. #7  
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    Quote Originally Posted by Pendragon
    Photographing radio waves? The idea sounds really cool,
    In a sense, this has already been done, think of radar or radio astronomy, in both cases however they look only at a very small segment of the spectrum, radar can be thought of in it's easiest sense as strapping a torch to a pair of binoculars then going out in the dark.
    Just as you can focus light waves, you can focus radio waves - so for example a satellite focuses it's transmitter on a particular area of the earth (called a footprint). If it were possible to see the whole range through a pair of spectacles, I suspect you would only see a 'fog' as pendragon suggests, occasionally with a few flashes as people used their mobiles.

    Correction, perhaps instead of fog you might see the world in a sort of black and white negative fashion where some objects absorb and some reflect the energy. It depends whether you want to see the radio waves or their effect, e.g you do not see 'light waves' you only 'see' the objects illuminated by them, A beam of light is only 'visible' if you blow smoke or other particulates through it - like lasers at a disco.
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  9. #8  
    Universal Mind John Galt's Avatar
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    Here is a photograph of M82 taken at radio wavelengths.
    http://www.jb.man.ac.uk/news/connected/M82radiotw.gif
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  10. #9 Re: Spectrum 
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    Quote Originally Posted by broken89
    Ok i know that it is possible to see the visible part of the spectrum and the infrared part of the spectrum with something like a camera with nightvision but is there any way to see radio waves with something like a camera?

    also i have a few more questions is the spectrum made entirely up of light?
    if light cant pass throught a solid object such a wall then how can radio waves?


    "Light" can be defined just as "radio waves with a frequency between 400 THz and 750 THz" (i dont remember the exact numbers).

    That is, light has the same properties as every radio wave, with the only special feature that human eye can detect it.

    Frequency makes the difference in radio waves behauviour, as well as polarization.

    You can consider a wall being like a filter: "frequencies above X GHz are strongly atenuated, and frequencies below X can pass through with little attenuation. Well, it's not so simple, but it can help.

    The same occurs with every wave-propagation aspect. For example, HF radiowaves can reflect in the ionosphere, while UHF can't.

    Greetings!
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