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Tesla Coil QRM
Posted by David C. on 6/1/2005, 12:43 am
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Re: Tesla Coil QRM
Posted by Bert Hickman on 6/1/2005, 9:16 pm, in reply to "Tesla Coil QRM" Hi Dave, Fortunately, Tesla coils are relatively poor radiators at their relatively low operating frequencies because their "antenna" is so small relative to their wavelength. However, the peak power in disruptive coils may be hundreds of kilowatts or even megawatts, so it doesn't take a very efficient radiator. Tesla Coils do radiate significantly at higher frequencies due to the spark gap in the primary circuit and the streamers coming off the topload. The negative resistance characteristic of a spark gap shock easily excites parasitic inductances and capacitances, creating VHF and UHF "hash" that can be quite significant near an operating coil. While radiation from the primary spark gap can be reduced somewhat by using relatively large ferrites on the leads going to the spark gap, you're pretty much stuck with the stuff coming off the secondary. And, because of the higher current, power arcs to ground radiate significantly more than air discharges. Once you're sure they won't kill you, you may want to try doing some Tesla Coil experiments with your (former?) friends in the club to see if you can get any actual radiation measurement data... :^) Best regards, Bert
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Re: Tesla Coil QRM
Posted by David C. on 6/2/2005, 10:37 am, in reply to "Re: Tesla Coil QRM" --Previous Message--
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Re: Tesla Coil QRM
Posted by Bert Hickman on 6/2/2005, 12:34 pm, in reply to "Re: Tesla Coil QRM" Bert --Previous Message--
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