• Hagdos@lemmy.world
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    6 hours ago

    AM doesn’t reach further than FM, it’s just that historically we’ve been using AM at lower frequencies, and these travel further. You could transmit with FM just as well on these frequencies, and get the same range.

    These radio telescopes don’t transmit anything at all, they listen to radio waves coming from the cosmos. Much like a normal telescope doesn’t transmit light.

    • cmhe@lemmy.world
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      4 hours ago

      These radio telescopes don’t transmit anything at all, they listen to radio waves coming from the cosmos. Much like a normal telescope doesn’t transmit light.

      If you invert the flow of the electrons, a receiver becomes a transmitter.

      Speakers can become bad microphones and vice versa. Pretty sure that a radio telescope is a very bad transmitter for human music, but it could be possible with some changes…

      • stevestevesteve@lemmy.world
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        3 hours ago

        if you invert the flow of electrons, a receiver becomes a transmitter

        Ehh not really. That’s kind of like saying if you invert the flow of photons, your eyes work as flashlights.

        “It could be possible with some changes” the changes would amount to removing the receiver and replacing it with a transmitter. In this specific case I’m not sure if a transmitter already exists at this antenna and it’s definitely possible one does, but that’s not a guarantee at all

        • cmhe@lemmy.world
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          44 minutes ago

          There is no such big differences between a light emitting (LED) and a light receiving diode (photodiode), they are just the reverse of each other. In fact photodiodes can even emit light, but very inefficiently. Same in reverse, LEDs can also detect light, just badly.