It is generally recognized that the first radio transmission was made from a temporary station set up by Guglielmo Marconi in 1895. This followed on from pioneering work in the field by a number of people including Alessandro Volta, André-Marie Ampère, Georg Ohm and James Clerk Maxwell.Mimi Colligan, Golden Days of Radio, Australia Post, 1991
The several potential contenders for the title of "oldest radio station" are listed below, organized by sign-on date. These are not restricted to radio broadcasting, i.e., the transmissions were not necessarily intended to reach a wide audience.
Stations
AM on mediumwave and longwave +Experimental and early radio stations (AM on mediumwave and longwave) Stationcall-sign(original) Stationcall-sign(current) City/location On air Transmission frequency(AM radio / FM radio) Broadcast classRoberto Landell de MouraN/ASão Paulo (between Paulista Avenue and Alto de Santana)1893 demonstration, which may have actually been optical transmission instead of radioGuglielmo MarconiN/ABroadcast across his garden in Pontecchio, Italy.1895ExperimentalAlthough Australia's first officially recognized broadcast was made in 1906, some sources claim that there were transmissions in Australia in 1897, either conducted solely by Professor William Henry Bragg of the University of Adelaide"TIME LINE – ESTABLISHMENT OF WIRELESS INSTITUTE OF AUSTRALIA"Bernard Harte, When Radio Was The Cat's Whiskers, 2002, privately published Dural, NSW or by Prof. Bragg in conjunction with G.W. Selby of Melbourne.N/A1897Experimental. Disputed in some sources.Guglielmo Marconi, first trans-Atlantic transmission.N/Afrom Poldhu, Cornwall to Signal Hill, St. John's, Newfoundland.December 1901Experimental(First official Morse Code transmission in Australia)N/Afrom Queenscliff, Victoria to Devonport, Tasmania1906Experimental (Reginald Fessenden experimental alternator station) BO"United States: Brant Rock, Mass.", List of Wireless-Telegraph Stations of the World (1 August 1907 edition), page 24. Brant Rock, Massachusetts, United States December 21, 1906 (Audio tests from various locations from as early as 1900) AM 50 kHz (approximately) ? W Lee de Forest (laboratory in the Parker Building) [?] New York City, New York, United States 1907 AM ? kHz (approximately) ? W (Beloit College Professor Dr. Charles Aaron Culver) [WBCR, WBNB, WEBW] Beloit, Wisconsin, United States 1907 AM ? kHz (approximately) now airs on 90.3 FM. ? W FN/SJN/6XF/6XE/KQW/"San Jose" KCBS San Jose, California/San Francisco, California 1909, 1921 (officially granted experimental license as KQW, become commercial in 1921, and KCBS in 1949) AM 740 kHz (Originally used 15 watts modulated with Carbon microphone) Class-B XWA CINW Montreal, Quebec, Canada August 1914 – December 1, 1919 – May 1922 – January 29, 2010 AM 940 kHz (Not original frequency). Considered by many Canadians to be "First scheduled broadcast station;" prior call sign CFCF stood for Canada's First, Canada's Finest. Class-A (Clear channel); XWA Experimental and W/T School station licence starting end of 1914,"Report of the Department of the Naval Service for the Fiscal Year ending March 31, 1915" regular broadcasting test emissions starting December 1, 1919, with XWA being replaced in May 1922 by private commercial broadcasting licence CFCF;Armstrong, R. (2015), "Broadcasting Policy in Canada", 2nd Edition, University of Toronto Press, p. 23; "LE RADIO – Programme du 25 juin", La Presse newspaper, Saturday 24 June 1922 AM station CINW ceased operations on January 29, 2010.2YUWRUCUnion College, Schenectady, New York1915"Union College", Education's Own Stations by S. E. Frost, Jr., PhD, 1937, pages 437–441.Various Frequencies AM, switched in 1975 to 90.9 FM, & moved in 1983 to 89.7 FM Original: Technical & Training School License, Current: Class-A 2XI WGY Schenectady, New York February 20, 1922 AM 810 kHz Class-A 9ZP, 9CLS KGFX Pierre, South Dakota The station's roots date back to 1912 when Dana McNeil, was first licensed as 9ZP. In 1916, he was licensed as 9CLS. According to the FCC's card file for the station, the broadcast license for KGFX was first issued on August 15, 1927, with the licensee listed as Dana McNeil, The station was originally at 1180 kHz, moving to 580 kHz in 1928. In 1932, it moved to 630 kHz, where it remained until 1967. As of 2018, KGFX 1060AM continues to broadcast local content at 10 kW power in Pierre, SD. With an FM translator broadcasting at 107.1 Various frequencies, 2XG New York City 1916 Unknown Unknown(see also Lee de Forest [above].) 8XK, 8ZZ KDKA Pittsburgh, Pennsylvania 1916 AM 1020 kHz 75 watts (1916), Class-A (1920–present). Began simulcasting on shortwave in 1923 as 8XS. Irish rebel station none General Post Office, Sackville Street, Dublin, Ireland April 24, 1916 Morse code only (Despite this claimed by some to be "world's first broadcast" as transmission not aimed at specific target) converted ship transmitter 9XM WHA University of Wisconsin–Madison, Madison, Wisconsin December 4, 1916 (regular Morse code weather broadcasts; first voice broadcast in February 1919; regular programming January 1921) AM 970 kHz Class-BFirst direct communication Australia to the United KingdomN/AAWA; Ernest Fisk; Sydney1918AM 21 kHzCarty, Bruce, On the Air – Australian Radio History, privately published Gosford NSW, page 257AC/7XCKJRSeattle, WA, USA1919AM 833 kHz/619 kHz, then various frequencies; currently AM 950 kHz & FM 102.9 MHzRádio Clube de Pernambucosame name as wellRecife, Pernambuco, 1919AM 720 kHzMade the first radiophonic broadcast in Brazil, but the first radio officially acknowledged was Rádio Sociedade do Rio de Janeiro (actually, Rádio MEC). Also, it is one of the oldest stations in the world.First Australian experiment in the broadcast of musicN/AAWA; Ernest Fisk; SydneyAugust 8, 1919AMDoubleday-Hill radio department station"Telephone Downtown Soon", "The Radio Amateur" by C. E. Urban, Pittsburgh Gazette Times, 26 October 1919, Sixth section, page 13."Wireless Phone Installed by Local Firm", "The Radio Amateur" by C. E. Urban, Pittsburgh Gazette Times, 25 January 1920, Fifth section, page 9.KQV"New Stations: Commercial Land Stations", Radio Service Bulletin, 1 November 1921, page 2.Pittsburgh, PennsylvaniaNovember 19, 1919"Radiophone Concert Schedule", "The Radio Amateur" by C. E. Urban, Pittsburgh Gazette Times, 15 February 1920, Second section, page 4. "Messrs. Williams and Devinney" were Burton P. Williams and Robert C. Devinney.Currently AM 1410 kHzCurrently Class D (Experimental Czech tests) Petřínská rozhledna (Petřín Lookout Tower), Prague, Czechoslovakia October 28, 1919 (Experimental) May 20, 1920 AM ??? kHz ?? kW 2MT (Marconi experimental station with a regular news service) Writtle, Chelmsford, Essex, England February 23, 1920 AM 107 kHz 15 kW LOR Radio Argentina LOR Buenos Aires, Argentina August 27, 1920