They transmitted Morse code at high speed, 100 - 200 words per minute, using automated paper tape readers. To achieve daylight communication at such long ranges they used frequencies in the very low frequency (VLF) band, from 50 to as low as 15 – 20 kHz. Industrial countries built worldwide networks of these stations to exchange telegram traffic with other nations at intercontinental distances and communicate with a country's overseas colonies. Transoceanic wireless telegraph stations were large high powered stations with huge antenna structures, with output power of 100 kW to one megawatt. Ships were allowed to communicate on three frequencies: 500, 660, and 1000 kHz. Marconi used several types of station:Ĭoastal stations communicated with wireless stations on ships, providing navigation and weather information and relayed communications from ships to other coastal stations and through telegraph systems. The first radio transmitters could not transmit audio (sound) like modern AM and FM transmitters, and instead transmitted information by radiotelegraphy the transmitter was turned on and off rapidly using a switch called a telegraph key, creating different length pulses of radio waves ("dots" and "dashes") which spelled out text messages in Morse code. Many of these have since been preserved as historic places. built the first radiotelegraphy communication stations, which were used to communicate with ships at sea and exchange commercial telegram traffic with other countries using Morse code. During the first two decades of the 20th century the Marconi Co. His company, the Marconi Wireless Telegraph Co, started in 1897, dominated the early radio industry. Guglielmo Marconi developed the first practical radio transmitters and receivers between 18. The feedlines feeding radio power from the transmitter to the huge flattop wire antenna are visible, top.Ī list of early wireless telegraphy radio stations of the Marconi Wireless Telegraph Co. A 1921 photograph of Albert Einstein being given a tour of The New Brunswick Marconi Radio Station in Somerset, New Jersey (then part of RCA) along with RCA officers and leading scientists and engineers in the electrical and radio fields from RCA, General Electric, American Telephone and Telegraph, and Western Electric.
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