
Listening radio with grass
About this video
Two experimenters hold blades of grass near a radio transmitter antenna and hear the AM station through the arc between antenna and grass. It is a short, informal demonstration of unintentional AM demodulation.
Why it appears in the archive
HN commenters bring it out whenever AM radio, strong transmitters or accidental demodulation comes up, as the classic example of grass playing radio.
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From the Hacker News discussion
Not exactly what you were asking for, but made me think of these: [LINK] and [LINK] and if you go down the rabbit hole, you end up here: [VIDEO]
Read original comment ↗I suspect it's accompanied by some speakers too, because otherwise the sound would be a lot "emptier" and less bassy. Similar device: [LINK] Also reminds me of this old video: [VIDEO]
Read original comment ↗Reminds me of this - [VIDEO] Obviously don't do this. I would be concerned about standing this close as well, radio burns are super nasty.
Read original comment ↗Fair point. Call it 60w or even 1w if that feels better. It's still many orders of magnitude over what you would be receiving across space from another solar system. Also, for mild amusement, your comment reminded me of this video [VIDEO]
Read original comment ↗AM radio is such a simple modulation scheme that even a piece of grass can be used to demodulate it, with enough power. [VIDEO]
Read original comment ↗Well, if you're mad enough and don't care about trivial things like life, you can listen to AM radio by just touching the mast with any random item: [VIDEO]
Read original comment ↗I grew up in a house that was next door to a radio rebroadcasting facility, and we could definitely hear the radio station coming from the walls of our house sometimes, e.g. even their station identification so there was no ambiguity. I assumed it was the house wiring (mostly knob and tube) acting as an antenna. I'm reasonably sure that was AM, though. Was the sound you heard like either of these? [LINK] [VIDEO]
Read original comment ↗Certainly a brass headboard doesn't have a semiconductor in it. But that doesn't mean the story is bullshit. Just that it's not working in the way they think it is. Heres an example of a thistle being used to convert an AM signal into audio. Granted, they are touching the plant directly to the broadcast tower, and it's outputting enough power that it starts burning and even burns the hand of the person holding the plant. [VIDEO]
Read original comment ↗