Art Unwin, KB9MZ wrote:
"If you place some circuit close to a normal dipole the circuit will
take some of the energy from the dipole via coupling such that the
circuit will oscillate and reradiate at its resonant frequency or at a
frequency determined by its particular coefficient of coupling."

Not exactly.. To obtain continuous oscillation requires a gain equal to
loss in a circuit and introduction from the output to the input of the
circuit a sufficient fraction in the proper phase to reinforce signals
in the circuit.

An oscillator is likely to have its frequency affected by any external
coupling. That`s a reason to shield an oscillator and to provide a
buffer between its output and external circuitry.

A characteristic of a radio wave is its amplitude and frequency lock to
the generator which produces it. Subsequent mistreatment of the wave by
its environment is usually incapable of altering its alternations.

Best regards, Richard Harrison, KB5WZI