>>9508660theres TWO DIFFERENT PRINCIPLES one is based on a "direct spark" transmission US645576, the other on Very Low Frequency (VLF) radio transmission US787412
one problem I had is that many times is not clear which system Tesla is talking about in the magazines, some times I found clues that he's talking about the "direct spark" this method is very clear I have no doubts about it (with high voltages the earth and atmosphere CAN really behave just like a conductor with low losses) but the VLF system does present "intricacies"...
first I'll explain the "spark" transmitter:
in the "direct spark" (discharge) device theres an arc going between two terminals one is a "transmitter" the other the "receiver" is similar to how spark-plugs in cars works but at MUCH higher voltages the spark or plasma arc is the conduct for the tranfers of the energy from one terminal to the other this is why he was able to obtain higher efficiencies because for the most part the energy is "directed" to one specific target its point-to-point so most of the energy makes it to the "receiver"
yes it is that simple
the technical analysis of this is that the atmosphere is formed by gases, one characteristic of gases is called "breackdown voltage", at a specific voltage gases become conductive, this is the main principle of spark-plugs, but keep in mind that they work at "low voltages" about 50Kvolts compared to MillionsVolts that tesla used.
https://patents.google.com/patent/US645576A/en?oq=645576>page2 parag.45 gases are known to be still nearly perfect insulators for ordinary (voltages) but they behave toward impulses of several millions of volts like excellent conductors>page4 parag.130 From my experiments and observations I conclude that with impulses not greatly exceeding fifteen or twenty million volts the energy of many thousands of horse-power may be transmitted over vast distances, measured by many hundreds and even thousands of miles 