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Sometimes it would be good to have a very tall antenna, but impractical to carry one of the requisite size. Persons in remote areas trying to receive signals might benefit from a tall antenna - likewise lunar or other explorers. I propose that a tall flame jet could serve as an antenna. Flame is
conductive by virtue of the ionized combustion products. Compressed gases can jet very tall flames. Such an antenna could be generated with a compressor and the fuel for a vehicle.
One could MacGyver up a cellphone augmenter using a campfire (or crashed vehicle) producing tall flames. Finally, for deep space communications, one could cause the flame jet from a rocket exhaust to serve as a long antenna. Chemical combustion rocket engines would make flame, but nuclear or even ion drives should serve if dense enough to conduct.
This would make a very slick science project. One could tune a little radio to a distant station. One could have a tall antenna handy and persons looking at the display could connect the tall antenna and hear how reception improves. One could then connect a tall flame jet (from a propane tank) and hear how the flame can function as an antenna as well. I suspect a neon sign could be an antenna if plugged in, but not if cold - again this would be a visually impressive component of a science fair project.
Pretty relevant-ish
http://flux.aps.org...8/abs/S4000009.html
Someone baked the caveman out of your antenna [GutPunchLullabies, Apr 06 2007]
Plasma Speakers
http://en.wikipedia...wiki/Plasma_speaker
Flame plasma conducts well enough to form an electrodynamic loudspeaker [csea, Apr 06 2007]
Plasma Antenna
http://www.laborato...ticl/rad/ar060e.htm
Russian paper with nice explanations and photos /diagrams [csea, Apr 07 2007]
[link]
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Shiny! And I love the idea of a cell phone with a ten meter flame spurting out of the top. Better use a headset though. |
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I have no sence at all whether or not this would work But sounds cool. I am not sure what all wave lengths come from a flame. I get a sence though that if it can pick it up, it puts out that wavelength when excited. Feel free to educate me on antennas. I have never noticed any radio interfearance from flames, like from power lines and engines and such. Whether that would mean nothing, that it would work or that it wouldn't pick up or recieve I don't know. |
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I beleive I have heard that the ionosphere on the dark side bounces short wave and AM? My guess is that excited by the sun light or solar wind it loosed the bouncy property. On that level I know it interacts. |
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Is flame really conductive? Because that is pretty cool. If Ionization is the only requirement, perhaps you would consider a powerful laser? Your antenna could be much longer and have, perhaps not less, but different risks to users. |
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I am not sure that a laser passing thru atmosphere would ionize its path adequately to conduct. For example, I cannot imagine completing a circuit using a laser pointer, but apparently a flame can do it. |
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I used to have a very ancient drier. The motor was unshielded. However, it caused interference on the TV upstairs only when the gas flame jet came on. My hypothesis: the flame jet acted as an antenna and transmitted to interference. |
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That plasma antenna linked by [Gut] sounds essentially like the neon tube I describe at the end of the idea. Although I did not use the term "afterglow mode". |
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Alternate hypothesis: The electrical ignition system ran continuously while the gas was on? |
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mmm. that is probably right. |
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I have just done a quick experiment
involving a candle, a digital multimeter
and a carrot. Conclusions: |
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1) A candle flame is less conductive
than a carrot |
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2) The plastic handles on my meter's
probes are not heat-resistant. |
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So, I suspect that the conductivity of a
flame is not high - but maybe high
enough to work as an antenna (I have
no idea). But a carrot antenna would be
cool too. |
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With a large enough flame you won't need to use any other form of communication. |
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Should be possible to make work. Could also work as the speaker (and perhaps even the microphone?) on a cellphone. Not even halfbaked, but a great millibaked idea. [link] |
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I demonstrated a plasma loudspeaker for a highschool science fair in 1972. It didn't work very well. |
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[MaxwellBuchanan] IIRC The conductivity of a flame depends on the applied voltage; you won't see much at the multimeter's applied voltage (9V.) It gets a whole lot better at several hundred volts. |
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This would suggest you could actually
speak via a burning bush, provided it
was wired in advance. |
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Apart from the conductivity, the antenna must be tuned to the wavelength, which means it must have a certain length. Right now, I can't think how that could be done with ionised air, unless there is a 'ground' terminal at the other end. |
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//The conductivity of a flame depends on
the applied voltage// Ah - OK. That's
weird, but I guess plasmae are weird. But
how does this relate to the voltages you'd
be using? |
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//you could actually speak via a burning
bush// Persumably to ask "who set my
bush on fire". |
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[Ling] Seems it would be fairly easy to vary the height by adjusting the rate of combustion. Quarter wavelengths, I suppose. I'm not sure exactly where the electrodes would need to go. On further thought, if they have to extend the length of the flame, one might as well use the wire as the antenna! Hmm, just did a search for "plasma antenna", and seems that such exist [link]. |
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"Private Parts, have you been monitoring
the emergency channel for any signal from
the downed aircraft?" |
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"No sir - sorry sir. I got distracted by that
enormous jet of flame on the horizon sir." |
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Farts are flammable. An anal wire could charge them but you'd have to eat gassy foods to have a long conversation. (plus asbestos pants) |
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