|
Sponsored Links
The term Wireless Telegraphy is a historic term used today as applied to early radio telegraph communications techniques and practices. Wireless telegraphy originated as a term to describe electrical signaling without the electric wires to connect the end points. The intent was to distinguish it from the conventional electric telegraph signaling of the day that required wire connection between the end points. The term was initially applied to a variety of competing technologies to communicate messages encoded as symbols, without wires around the turn of the twentieth century with radio emerging as the most significant. These other competing wireless telegraphy technologies are interesting, but pale in significance. Wireless telegraphy rapidly came to be synonymous with Morse Code transmitted with electromagnetic waves decades before it came to be associated with the term radio. Wireless telegraphy is used widely today by amateur radio hobbiests where it is commonly referred to as continuous wave (CW) radio telegraphy, or just CW. The term Wireless Telegraphy came into widespread use around the turn of the previous century when Spark-gap transmitters and privative receivers made it practical to send telegraph messages over great distances, enabling transcontinental and ship-to-shore signalling. Before that time, wireless telegraphy was an obscure experimental term that applied collectively to an assortment of sometimes unrelated signaling schemes. It included such schemes as large mechanical arms for visual signaling and electrical currents through water and dirt. As far back as Faraday and Hertz in the early 1800s, when it was discovered that radio waves could be used to send telegraph messages. In 1832, James Bowman Lindsay gave a classroom demonstration of UHF wireless telegraphy to his students. By 1854 he was able to demonstrate transmission across the Firth of Tay from Dundee to Woodhaven (now part of Newport-on-Tay), a distance of two miles.[citation needed] Various wireless telegraphy devices started appearing in the 1860s. Heinrich Hertz demonstrated the existence of electromagnetic radiation (radio waves) in a series of experiments in Germany during the 1880s. In St. Louis, Missouri, Nikola Tesla made the first public demonstration of a modern wireless system in 1893. Addressing the Franklin Institute in Philadelphia and the National Electric Light Association, he described and demonstrated in detail the principles of wireless telegraphy and radio. The apparatus that he used contained all the elements that were incorporated into radio systems before the development of the vacuum tube. This led to work in using radio signals for wireless communication, initially with limited success. Using spark-gap transmitters plus coherer-receivers were tried by many experimenters, but several were unable to achieve transmission ranges of more than a few hundred metres. This was not the case for all researchers in the field of the wireless arts, though.[1][2] By 1897, Guglielmo Marconi conducted a series of demonstrations with an economical radio system for signalling for communications over practical distances. This helped popularize radio communication activity worldwide, which is covered in depth by Invention of Radio and History of Radio.
|
Wireless Telegraphy Subcategories
Wireless Telegraphy Articles
|
|
