Page 1-2 (Naoki Shinohara: Wireless Power Transfer via Radiowaves)
During the same period, when Marchese G. Marconi and Reginald
Fessenden pioneered communication via radiowaves, Nicola Tesla
suggested the idea of wireless power transfer and carried out the
first WPT experiments in 1899 [TES 04a, TES 04b]. He said “This energy
will be collected all over the globe preferably in small amounts
ranging from a fraction of one to a few horse-power. One of its chief
uses will be the illumination of isolated homes”. Tesla actually built
a gigantic coil that was connected to a 200 ft high mast with a 3 ft
diameter ball at its top. The device was called the “Tesla Tower”
(Figure 1.1). Tesla fed 300 kw of power to the coil that resonated at
a frequency of 150 kHz. The radio frequency (RF) potential at the top
sphere reached 100 MV. Unfortunately, the experiment failed because
the transmitted power was diffused in all directions using 150 kHz
radiowaves, whose wavelength was 21 km. After this first WPT trial,
the history of radiowaves has been dominated by wireless
communications and remote sensing.
What does radio frequency potential mean here?
Best Answer
Potential means "voltage relative to ground" so they had RF AC voltages of 100 MV relative to the ground / earth potential which is defined as 0 V (zero Volt).