Hertz experiment and Tesla "magnifying" transmitter are very different setups.
In Hertz experiment, the radiating part which constitutes also the resonant circuit is short: it's a 2 mtrs dipole with terminal capacities and the spark gap is at the center. Therefore the resonant frequency is very high. Hertz used a reflector at 12 mtr from the transmitter to produce standing waves, and shown by this way that 1) the wavelength was around 4 mtr, i.e. a frequency of 75 Mhz, and 2) it was really a propagation because the wave must go back and forth to build the standing wave: Hertz waves really radiate.
Tesla used very low frequencies. At these frequencies, he couldn't observe standing wave due to the wavelength which is by many orders longer than any distance at which he could receive a signal.
Unlike the Hertz experiment, a coil probe or capacity probe anywhere around a Tesla resonant circuit will show the same phase whatever the distance from the circuit because this distance is always short in comparison with the wavelength. In Tesla's experiments, the receiver is simply in the very "near field" from the transmitter (i.e. << quarter-wavelength). None propagation can be observed, but only the electric or magnetic field that couple with the resonant receiver. And when we try to move far away from the transmitter, i.e. at distance of several wavelengths, the signal can't be received because it fades very quickly. The reason is that an antenna whose the length is short in comparison with the wavelength, radiates EM waves very poorly. This fact is confirmed by the observation that a resonant circuit with a high Q like those of Tesla is maintaining the oscillations for a long time, many periods, after the power source of oscillations is disconnected. This means that the energy is kept in the circuit and doesn't radiate under any kind of waves.
Please bear with me ex. I agree with you a lot, but... EDIT: Yes I see, what you are saying is absolutely correct when we deal with
the shorter 1/4 wave lengths (frequencies) not in resonance with the planet. If the planet is resonating then the effect can be had in differing magnitudes anywhere
the ground can be connected to with a receiver. If too high a frequency is used then the disturbance fades out most definitely,
Tesla describes this in the book The Inventions Researches and Writings of Nikola Tesla. A very early realization/observation.
I'm not clear on what constitutes a "near" field, what constitutes "near field" effects ?
Because if a Tesla transmitter was placed on one side of the planet and a receiver was
placed on the other I can't see how their electric and magnetic fields are shared.
Shared fields to me implies that the receiver is in the inductive influence of the transmitter,
I don't think it would be.
First imagine there is no ground disturbance and the setup is off, the transmitter and receiver elevated capacitances are sitting in
their respective electric fields, they could be at a different potential with respect to the Earth, eg. with the transmitter, it's terminal could be
at 1000 volts while the receiver is at 100 volts or the other way when the system is at rest (atmospheric potential - electric field).
Then when the system is run the ground is disturbed so an alternating potential is created because of the alternating potential of the
ground, the top terminal is referenced to it's electric field and acts like a neutral ground while the ground disturbance creates the potential difference to drive the current
through the ground/receiver. I doubt very much that the receiver if disconnected from the ground would have current induced in it by the transmitter on the opposite side of the planet
so I doubt also that it is in an inductive relationship.
I think to even get 1/4 WL resonance there must be a forward and reflected wave-interference to produce a standing 1/4 wave resonance ?.
I don't think near field effects scale up, I think they are an effect of the voltage/frequency maybe or some kind of relative relationship.
Cheers
P.S. The Earth is resonating at multiples of 50/60 Hz all the time I think. There is energy to collect but the ground is disturbed
by the electricity company and the receiver would be expensive to build, as well as it could be considered stealing and the amount of energy to collect
may not be much either.