What kind of effect would result from a spark gap transmitter powered by lightning?

Question

Would there be any HERF/EMP effect by creating a HUGE copper antenna and coil which was powered by attaching a long wire to a model rocket and firing it during a lightning storm, hoping the lightning strikes the rocket/wire and following it down into the coil and antenna then going through a spark gap and into the ground? No I'm not going to try it, just curious. I know this sounds stupid, but I would like mature, serious answers only. Please don't answer "I don't know" just for the points!

Answer 1

See the reference for how the spark gap transmitter worked.  The spark generated a signal that was essentially white noise, with energy distributed across the whole spectrum.  But the tuned circuit resonated at a single frequency, so the energy at other frequencies was dissipated.  The lightning strike would just provide a single pulse, whose timing you couldn't control.

The setup you described would actually operate as a spark gap transmitter during the lightning pulse, but the signal would be undetectable, since it would be overwhelmed by the signal produced by the much larger spark of the lightning itself.

Think more along the lines of a lightning rod rather than a rocket and a wire.  The wire would likely be vaporized too quickly to even test.  Set up the lightning rod on a natural peak (not a building) when it isn't storming!  Observe it from a distance with a recording radio receiver with a spectrum analyzer.

Answer 2

Why would you think that there wouldn't be any HERF or EMI?  Marconi's first transmissions were based on spark gaps: http://en.wikipedia.org/wiki/Spark-gap_t...

However, your concept would be

>  absurdly expensive, since the rocket and lead wire will get destroyed

>  absurdly time consuming, waiting for the right conditions

>  absurdly expensive, since the FCC would probably fine you for interfering with local radio and other transmissions, think multi-kilodollars here

It would be more practical to simply duplicate Marconi's transmitter.  The lower power would at least keep you from getting into hot water with the FCC.

HERF  -- Hazards of Electromagnetic Radiation on Fuel

EMP -- Electromagnetic Pulse

Answer 3

Well, I don't know what a HERF/EMP effect is, but if it means the copper antenna and coil increasing the amount of RF radiation, like when Marconi used a spark transmitter to transmit a radio signal from Cornwall to Newfoundland, the answer is yes, it would work.  With an ordinary radio receiver, you get crackling from nearby lightning strikes.  With the experiment you describe, I'd guess that you'd be able to pick up the interference at intercontinental distances.  By the way, what is the HERF/EMP effect please?  My email is [e-mail].