Because you use light to communicate in sign language, and light is just an electromagnetic wave like radio but on another frequency. You just need to be in line of sight

  • wipasoda@lemmy.worldOP
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    1 year ago

    Exactly, I’d still place bursts of radio signals (like that of a pulsar or morse code transmitter) under the umbrella term “radio communication”. Just because it uses the radiation that is at the radio frequency. No matter what the format/arrangement/method, which includes encoding and using carrier waves.

    Then you also have electric waves that travel through conductors, although this is only a part the electromagnetic wave used in the air. But you can change the frequency of this electric wave perhaps to the radio frequency. So perhaps there is also radio communication through wires