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Re: tuning coils
Tesla List wrote:
> If I wanted to construct a receiving coil to receive the generated
> transmission of a Tesla coil to experiment with local wireless
> transmission (ala Richard Hulls experiments), but instead of the same
> size coil or same frequency, could it be a smaller coil at an harmonic
> of the larger? I guess that's more my specific question. If I'm to
> understand you correctly, I should be able to do it if I keep the
> harmonic below 1gH?
For best coupling, the frequency of the receiver must match the
frequency
of the transmitter. And if you want reasonable coupling coefficient, so
there is time to collect some energy (not only signal) before everything
is dissipated, the receiving coil shall be as large as possible, and the
Q of the receiving circuit shall be as high as possible.
> A radio tower is massive and generates megawatts of RF. But the receiver
> in a radio is small and tunes to the proper frequency. Can I mimic this
> with a tesla coil and a smaller receiving coil for a series of
> experiments I want to perform? I know there will be losses. I just want
> to know if the idea is viable.
A small receiver will perform as well as a small radio receiver,
receiving microvolts of signal if far from the transmitter.
But if the transmitter is at short distance, useful energy can be
received. A similar system is used to power microcircuits that use a
small loop antenna tuned to a particular frequency as power supply.
These circuits are activated when a powerful transmitter is nearby.
Applications are identification devices that are attached to railroad
cars, containers, or even implanted under the skin of animals. They
transmit an identification code once powered.
Antonio Carlos M. de Queiroz