• Daemon Silverstein@thelemmy.club
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    20 days ago

    I once saw a video of a person touching a grounded sausage to the metallic structure of an AM radio tower, the transmission was audible as the sausage was being zapped. If there’s a merely conductible thing grounded near the tower, I guess it’ll sort of “coil whine” (a well-known phenomenon when electrical components physically vibrate due to the passage of current), converting to sound whatever it’s being transmitted at the moment. This includes the tower structure itself, if the electrical grounding isn’t properly done or if there’s some grounding leak. Otherwise, a grounded thing touching the tower would suffice to convert the transmission into sound, if those radio-telescopes use AM modulation (I’d guess they do, because AM modulation is known for reaching longer distances than FM).

    • Hagdos@lemmy.world
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      19 days 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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        19 days 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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          19 days 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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            19 days 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.

            It seems like most efficient energy conversion methods can be used in both directions.

            • Strykker@programming.dev
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              18 days ago

              Yes, but you would blow out most of the amplification circuitry in a radio telescope reciver if you tried to use it for broadcast at any kind of power.