WELCOME TO RADIO COMMUNICATION

.=jkajsoq,s ikaksfjSokh.`jkajsoq,sh hkq jsoHq;a pqusNl ;rx. ixLHd; l%uj;aj ilid iusfm%aIKh lsrSu ioyd ksmojQ fuj,uls’ jd;fha iy wjldYh ;`, we;s rsla;l ;`, jsoHq;a pqusNl lafIa;% foda,kh jSu ksid jsoHq;a pqusNl mKsjQv yqjudrej isoqfjhs’ mKsjQv yqjudre jkafka l%uj;aj ilik,o jslsrKYS,S ;rx.hla jsia;drhla” ixLHd;hla” l,dmhla ;`, .uka lsrSu u.sks’ .`jkajsoq,s ;rx. jsoHq;a ikakdhlhla f,i yqjudre jSfusos ikakdhlhla f,i m%;Hdjra;l Odrdj,a foda,k l,dm ;`, fm%arKh lrhs’ iusfm%aIKh jQ f;dr;`re u.ska

mrskdus; fjk;a ix{d iy Ynso wkdjrKh lr.; yel’

jsoHq;a pqusNl ;rx. ksl`;a lrk l`,qKla

German troops erecting a wireless field telegraph station during World War I

b;Sydihfuh mqoa.,hska lsNSmfofkl`f.a iNyd.sJjfhkA ksmojkQ ,enqjls’19 jk ishjfiNs PSj;a jQ fY%aIaV jsohd{hskaf.a uNkaisfha m%;sM,hla f,i /yeka rys; jsoq,s mKsjqv hejSfus l%uh fidhd.kakd ,oS’

fuhg m%uqlJjh oelajq jsoHd{hska}Jagadish Chandra Bose Guglielmo MarconiAlexander Stepanovich Popov Nikola TeslaErnest Rutherford Alexander Popov

1901oS m%:u jdksPuh .`jkajsoq,s fiajdj wdrusN jsh’

w;S;fha .`jkajsoq,s mKsjqv hejSfus l%uh Ndjs;d lsrSu isoqjQfha MORSE CODE NdjS;d lSrsu u.SkS

1jk f,dal hqoaOfhaos kdjsl fin,qka yd hqO fin,qka w;r wdrlaIl f;dr;`re yqjudre lrf.k we;af;ao .`jkajsoq,s mKsjqv hejSfus l%uh Ndjs;d lrf.kh’jrA:udkfha Px.u oQrl:k ;dlaIKh nsNsjs we;af;ao /yeka rys; .`jkajsoq,s mKsjqv hejSfus l%uh Wmfhda.s lrf.kh’

Classic radio receiver dial

GuglielmoGuglielmo MarconiMarconi• Guglielmo Marconi was an electrical engineer and Nobel was an electrical engineer and Nobel

laureate known for the development of a practical wireless laureate known for the development of a practical wireless telegraphy system.telegraphy system.

• In 1896, In 1896, Guglielmo Marconi was awarded a patent for radio was awarded a patent for radio with with British Patent 12039, 12039, Improvements in Transmitting Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-forElectrical Impulses and Signals and in Apparatus There-for. . This was the initial patent for the radio, though it used This was the initial patent for the radio, though it used various earlier techniques of various other experimenters various earlier techniques of various other experimenters (primarily Tesla) and resembled the instrument demonstrated (primarily Tesla) and resembled the instrument demonstrated by others (including Popov). During this time spark-gap by others (including Popov). During this time spark-gap wireless telegraphy was widely researched.wireless telegraphy was widely researched.

• In 1896, Bose went to London on a lecture tour and met In 1896, Bose went to London on a lecture tour and met Marconi, who was conducting wireless experiments for the Marconi, who was conducting wireless experiments for the British post office. In 1897, Marconi established the radio British post office. In 1897, Marconi established the radio station at station at Niton, Isle of Wight, , England. In 1897, Tesla applied . In 1897, Tesla applied for two key radio patents in the USA. Those two patents were for two key radio patents in the USA. Those two patents were issued in early 1900. In 1898, Marconi opened a radio factory issued in early 1900. In 1898, Marconi opened a radio factory in Hall Street, in Hall Street, Chelmsford, England, employing around 50 , employing around 50 people. In 1899, Bose announced his invention of the "iron-people. In 1899, Bose announced his invention of the "iron-mercury-iron coherer with telephone detector" in a paper mercury-iron coherer with telephone detector" in a paper presented at Royal Society, London.presented at Royal Society, London.

Jagdish Chandra BoseJagdish Chandra BoseIn November 1894, the In November 1894, the Indian physicist, physicist, Jagdish Chandra Bose, demonstrated publicly the use of radio waves in , demonstrated publicly the use of radio waves in Calcutta, but , but he was not interested in patenting his work.he was not interested in patenting his work.[10] Bose ignited Bose ignited gunpowder and rang a bell at a distance using electromagnetic gunpowder and rang a bell at a distance using electromagnetic waves, proving that communication signals can be sent without waves, proving that communication signals can be sent without using wires. He was thus the first to send and receive radio using wires. He was thus the first to send and receive radio waves over a significant distance but did not commercially waves over a significant distance but did not commercially exploit this achievement.exploit this achievement.The 1895 public demonstration by Bose in The 1895 public demonstration by Bose in Calcutta was before was before Marconi's wireless signalling experiment on Marconi's wireless signalling experiment on Salisbury Plain in in England in May 1897.England in May 1897.[11][12] In 1896, the In 1896, the Daily Chronicle of of England reported on his UHF experiments: "England reported on his UHF experiments: "The inventor (J.C. The inventor (J.C. Bose) has transmitted signals to a distance of nearly a mile and Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable herein lies the first and obvious and exceedingly valuable application of this new theoreticalapplication of this new theoretical marvel. marvel.""

Nikola Tesla

Nikola Tesla developed means to reliably produce radio developed means to reliably produce radio frequencies, publicly demonstrated the principles of radio, and frequencies, publicly demonstrated the principles of radio, and transmitted long distant signals. He holds the US patent for the transmitted long distant signals. He holds the US patent for the invention of the radio, as defined as "wireless transmission of invention of the radio, as defined as "wireless transmission of data".This box: data".This box: view •  • talkNikola TeslaNikola Tesla

In 1891 Tesla began his research into radio. He later published In 1891 Tesla began his research into radio. He later published an article, "an article, "The True Wireless", concerning this research.", concerning this research.[4] In In 1892 he gave a lecture called "1892 he gave a lecture called "Experiments with Alternate Currents of High Potential and High Frequency", in London (Available at Project Gutenberg).", in London (Available at Project Gutenberg).[5] In 1893, at In 1893, at St. Louis, Missouri, Tesla gave a public demonstration of ", Tesla gave a public demonstration of "wireless" radio communication. Addressing the " radio communication. Addressing the Franklin Institute in in Philadelphia and the and the National Electric Light Association, he , he described in detail the principles of radio communication.described in detail the principles of radio communication.[6]

The apparatus that Tesla used contained all the elements that The apparatus that Tesla used contained all the elements that were incorporated into radio systems before the development of were incorporated into radio systems before the development of the "oscillation valve", the early the "oscillation valve", the early vacuum tube. Tesla initially used . Tesla initially used sensitive sensitive electromagnetic receivers, receivers,[7] that were unlike the less that were unlike the less responsive responsive coherers later used by Marconi and other early later used by Marconi and other early experimenters.experimenters.

Afterward, the principle of radio communication (sending signals Afterward, the principle of radio communication (sending signals through space to through space to receivers) was publicized widely from Tesla's ) was publicized widely from Tesla's experiments and demonstrations. Various scientists, inventors, experiments and demonstrations. Various scientists, inventors, and experimenters began to investigate wireless methods. For and experimenters began to investigate wireless methods. For more information see more information see Tesla's wireless work

Oliver Lodge

• Oliver Lodge transmitted radio signals on August 14, 1894 (one year after Tesla, five years after Heinrich Hertz and one year before Marconi) at a meeting of the British Association for the Advancement of Science at Oxford University.[8] (In 1995, the Royal Society recognized this scientific breakthrough at a special ceremony at Oxford University. For more information, see Past Years: An Autobiography, New York: Charles Scribner's Sons, p231.)

• On 19 August 1894 Lodge demonstrated the reception of Morse code signalling via radio waves using a "coherer". He improved Edouard Branly's coherer radio wave detector by adding a "trembler" which dislodged clumped filings, thus restoring the device's sensitivity. [9] In August 1898 he got U.S. Patent 609,154, "Electric Telegraphy", that made wireless signals using Ruhmkorff coils or Tesla coils for the transmitter and a Branly coherer for the detector. This was key to the "syntonic" tuning concept. In 1912 Lodge sold the patent to Marconi.

Alexander Popov Popov was the first man to demonstrate the practical applications of radio waves. In 1895, the Russian physicist Alexander Popov built a coherer. On May 7, 1895, Popov

performed a public demonstration of transmission and reception of radio waves used for communication at the Russian Physical and Chemical Society, using his coherer:[13] this day has since been celebrated in Russia as "Radio Day". He did not apply for a patent for this invention. Popov's early experiments were transmissions of only 600 yards (550 m). Popov was the first to develop a practical communication system based on the coherer, and is usually considered by the Russians to have been the inventor of radio.[14][15]

Around March 1896 Popov demonstrated in public the transmission of radio waves, between different campus buildings, to the Saint Petersburg Physical Society. (This was before the public demonstration of the Marconi system around September 1896). Per other accounts, however, Popov achieved these results only in December, 1897; that is, after publication of Marconi's patent.[16] In 1898 his signal was received 6 miles (9.7 km) away, and in 1899 30 miles away. In 1900, Popov stated at the Congress of Russian Electrical Engineers that,

"the emission and reception of signals by Marconi by means of electric oscillations was nothing new, as in America Nikola Tesla did the same experiments in 1893."[17][18]

Later Popov experimented with ship-to-shore communication. Popov died in 1905 and his claim was not pressed by the Russian government until 1945.

Around 1895: 3-way near photofinish for first use of radio In March 1895, Popov transmitted radio waves between campus buildings in

Saint Petersburg, but did not apply for a patent.

Ernest Rutherford

• The New Zealander Ernest Rutherford, 1st Baron Rutherford of Nelson was instrumental in the development of radio. In 1895 he was awarded an Exhibition of 1851 Science Research Scholarship to Cambridge. He arrived in England with a reputation as an innovator and inventor, and distinguished himself in several fields, initially by working out the electrical properties of solids and then using wireless waves as a method of signalling. Rutherford was encouraged in his work by Sir Robert Ball, who had been scientific adviser to the body maintaining lighthouses on the Irish coast; he wished to solve the difficult problem of a ship’s inability to detect a lighthouse in fog. Sensing fame and fortune, Rutherford increased the sensitivity of his apparatus until he could detect electromagnetic waves over a distance of several hundred meters. The commercial development, though, of wireless technology was left for others, as Rutherford continued purely scientific research. Thomson quickly realised that Rutherford was a researcher of exceptional ability and invited him to join in a study of the electrical conduction of gases.

Telephone Herald in Budapest, Hungary (1901).

Donald Manson working as an employee of the Marconi Company (England, 1906)

.`jka jsoq,sfha jsldYkh

A Fisher 500 AM/FM hi-fi receiver from 1959.

American girl listens to radio during the Great Depression.

Pure One Classic- DAB Digital Radio from 2008

Amateur radio station with multiple receivers and transceivers

Bush House, home of the BBC World Service.

YS% ,xldfjs .`jkajsoq,s wdh;k

Lakhanda

87.9 MHz88.5 MHz97.6 MHz

North, North Central, North Western (Karagahatenna)Island Wide (Nayabedda, Yatiyantota)Kandy & Southern (Deniyaya, Hunasgiriya)

WickramasinghapuraBattaramulla'World Service' transmitted via APSTAR 2R satellite (76.5°E) 3.652 GHz Transponder 2 A Horizontal-Linear 6.5 Ms/Sec

HIRU 94.7 MHz94.7 MHz95.3 MHz96.7 MHz96.7 MHz

Kandy (Hunasgiriya)Rajarata (Gammaduwa)Island Wide (Nuwara Eliya)ColomboRuhuna (Gongala)

SHAKTHI FM

91.2 MHz91.5 MHz103.8 MHz105.1 MHz105.1 MHz105.1 MHz

Bandarawelle (Nayabedda)Kandy (Hunasgiriya)Upcountry & Islandwide (Mt Oliphant, Nuwara Eliya)ColomboMatale (Karagahatenna/Gammaduwa)Southern Sri Lanka (Gongala)

Braybrooke Place

Colombo

SIRASA FM

88.8 MHz101.7 MHz106.2 MHz106.2 MHz106.5 MHz106.5 MHz

Central Sri Lanka (Mt Oliphant, Nuwara Eliya 4 kW)Rajarata, Northern & Eastern Sri Lanka (Gammaduwa)Kandy (Hunasgiriya, 2 kW)Southern Sri Lanka (Gongala)Colombo (Union Place, 2 kW)Uva (Nayabedda)

PO Box 25

Araliya Uyana

Pannipitiya

Y FM 91.2 MHz92.6 MHz99.1 MHz101.3 MHz101.3 MHz

KandyColombo (Araliya Uyana, Depanama, Pannipitiya)North Central (Gammaduwa)Southern Sri Lanka (Gongala)Uva (Nayabedda)

Formerly Classic FM

7 Braybrooke Place

Colombo 2