Short answers, pulled from the story.
German physicist Heinrich Hertz established the first practical radio antennas for scientific demonstration in 1886. He used dipole antennas at the focal point of parabolic reflectors to both transmit and receive signals.
The word antenna comes from Italian where l'antenna means tent pole. Guglielmo Marconi called his elevated horizontal wire antenna simply l'antenna because it resembled a tent pole on his father's estate near Bologna starting in 1895.
An antenna converts an alternating electric current into radio waves during transmission. It intercepts power from a radio wave to produce an electric current during reception while radio waves travel through space at the speed of light with almost no transmission loss.
Omnidirectional antennas radiate energy approximately equally in all horizontal directions as demonstrated by a vertical whip antenna found on portable radios. Directional beam antennas concentrate radio waves in specific angles instead using passive elements like those in a Yagi-Uda array.
An antenna designed for 1 meter wavelength would be approximately 50 cm from tip to tip. Each element is approximately one quarter wavelength long and standing waves form within the conductor when the signal frequency matches the design length.