Transmitting Radio Signals over EM Waves

The German scientist Heinrich Hertz demonstrated in 1887 that electrical
energy could be transmitted through space by way of EM waves. Even though
Professor Hertz was the first to demonstrate this phenomenon, he did not grasp
the impact of his discovery. It took the work of Nikola Tesla and Guglielmo
Marconi, who were inspired to use Hertz’s discovery to transmit signals—thus,
the first radio was born.
Electric fields are induced by the separation of positive and negative charges.
Moving charges (electric current flow) induce electric fields. Changing electric
fields induces magnetic fields.Therefore, alternating current flow—such as current flow into and out of an antenna—induces an oscillating electric field, which then
induces an oscillating magnetic field.An EM wave is the propagation of electrical
energy caused by oscillating electric fields inducing oscillating magnetic fields,
which then induce further oscillating electric fields, which then induce further
oscillating magnetic fields, and so on