Hello, everyone. Today, I’d like to share Don Smith’s fundamental RF principle. Using some equipment, I’ll demonstrate how high-frequency RF, at 100 MHz or more, can feed a pure high-Q antenna at the transmitter. This process creates a reactive near-field zone around the coil using Don Smith's secret: pure magnetic resonance.
In this setup, the reactive field induces a vibration in a nearby high-Q resonant mirror antenna. The beauty of this reactive field lies in its ability to separate the electric (E) and magnetic (M) components since they are highly out of phase as reactive power. While this reactive power isn’t directly usable, it can stimulate a state of magnetic RF resonance.
At the right frequency and within the reactive near-field zone—typically up to the wavelength of the frequency in use—the receiving antenna selectively couples to the magnetic component. This results in the generation of a real in-phase sine wave AC current with usable power, entirely decoupled from the primary system.
This effect bypasses the traditional limitations of mutual inductive coupling seen in standard transformers. However, finding the "sweet spot" is essential. This is the precise location within the near-field zone where the transmitter antenna neither reflects power back to the input nor stresses it with additional current demands. Instead, it enables the creation of a localized, self-sustained current.
The sweet spot can be as narrow as half an inch, making it challenging to identify without specialized equipment. Being too close results in reflections or opposing fields, while being too far places you in the far-field radiative RF zone. At that distance, Maxwell’s principles reassert themselves, and the EM waves are locked in a 90-degree phase relationship, rendering high-Q antennas unable to decouple the E and M components.
Once the sweet spot is located, you can build higher-Q antennas to generate high voltages and increase real AC current in phase. As Don Smith emphasized, it’s all about achieving magnetic resonance in phase. The equipment is needed to measure the actual reflection and transmitted power ratios on the primary high Q transmitter antenna.
My apologies for referring to the scope reading as micro-volts instead of millivolts. I simply misspoke.
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