Richard Clark wrote:
An electron does not always give rise to just one photon, or any
photon, or a photon of the same energy.

This is true. But in an amateur transmitter driven
antenna system, the great majority of radiated photons
are coherent with the transmitting frequency. Coherent
photons are required to have the same energy level. The
photons coherent with the transmitting frequency are
first order effects. Assuming one is not close to
another transmitter, the photons not coherent with
the transmitting signal are Nth order effects.
--
73, Cecil http://www.w5dxp.com