Greek runner Pheidippides, Athenian courier is sent to Sparta to request help when the Persians landed at Marathon - runs 150 miles in two days. Early discoveries of Electricty and Magnetism can be found in the annals of history, names such as Gilbert, Von Guericke, Volta, Oersted, Wheatstone, Cooke, Faraday, Ampere, Ohm, Davy, all contribute to the ultimate development of wireless. Early Pioneers and Inventors include, Maxwell, Marconi, Loomis, Edison, Henry, Hertz, Feddersen, Von Bezold, Hughes, Stokes, Tesla, Henry, Bell, Preece, Hertz, Branly, Dodge, Braun, Lodge, and Popoff all lay the foundation of wireless Samuel F. ' the two coasts of the United States were linked by telegraph.
Arc transmitters were widely used at both shore stations and on ships.
One of the more powerful arc transmitters constructed were the 1,000 watt units built for the U. By gradually scaling up the equipment Federal Telegraph finally produced a 30 k W unit that outperformed a powerful rotary spark transmitter at the Navy's Arlington station.
The navy wanted still more power and Elwell thought he could build a 60 k W unit by merely scaling up the parts again. Arc transmitters were gradually eliminated when the new vacuum tube transmitters came into use. Perhaps the last to be in operation on land were the stations operated by the Mackay Radio and Telegraph Company between cities on the Pacific coast.
In the way of development after Marconi's high voltage spark gap came the use of high voltage transformers to generate the spark gap voltage. Here a 500 Hz generator, a step up transformer, and a rotary spark gap was used used to create the high voltage.
The ultimate came in the powerful transmitters such as those at the U. Some of these produced a deafening noise created by the spark.