<P> At the turn of the 20th century , Marconi began investigating the means to signal completely across the Atlantic in order to compete with the transatlantic telegraph cables . Marconi established a wireless transmitting station at Marconi House , Rosslare Strand , Co . Wexford in 1901 to act as a link between Poldhu in Cornwall , England and Clifden in Co . Galway , Ireland . He soon made the announcement that the message was received at Signal Hill in St John 's , Newfoundland ( now part of Canada ) on 12 December 1901 , using a 500 - foot ( 150 m ) kite - supported antenna for reception -- signals transmitted by the company 's new high - power station at Poldhu , Cornwall . The distance between the two points was about 2,200 miles ( 3,500 km ) . It was heralded as a great scientific advance , yet there also was -- and continues to be -- considerable scepticism about this claim . The exact wavelength used is not known , but it is fairly reliably determined to have been in the neighbourhood of 350 meters ( frequency ≈ 850 kHz ) . The tests took place at a time of day during which the entire transatlantic path was in daylight . We now know ( although Marconi did not know then ) that this was the worst possible choice . At this medium wavelength , long distance transmission in the daytime is not possible because of heavy absorption of the skywave in the ionosphere . It was not a blind test ; Marconi knew in advance to listen for a repetitive signal of three clicks , signifying the Morse code letter S . The clicks were reported to have been heard faintly and sporadically . There was no independent confirmation of the reported reception , and the transmissions were difficult to distinguish from atmospheric noise . ( A detailed technical review of Marconi 's early transatlantic work appears in John S. Belrose 's work of 1995 . ) The Poldhu transmitter was a two - stage circuit . </P>
<P> At the turn of the 20th century , Marconi began investigating the means to signal completely across the Atlantic in order to compete with the transatlantic telegraph cables . Marconi established a wireless transmitting station at Marconi House , Rosslare Strand , Co . Wexford in 1901 to act as a link between Poldhu in Cornwall , England and Clifden in Co . Galway , Ireland . He soon made the announcement that the message was received at Signal Hill in St John 's , Newfoundland ( now part of Canada ) on 12 December 1901 , using a 500 - foot ( 150 m ) kite - supported antenna for reception -- signals transmitted by the company 's new high - power station at Poldhu , Cornwall . The distance between the two points was about 2,200 miles ( 3,500 km ) . It was heralded as a great scientific advance , yet there also was -- and continues to be -- considerable scepticism about this claim . The exact wavelength used is not known , but it is fairly reliably determined to have been in the neighbourhood of 350 meters ( frequency ≈ 850 kHz ) . The tests took place at a time of day during which the entire transatlantic path was in daylight . We now know ( although Marconi did not know then ) that this was the worst possible choice . At this medium wavelength , long distance transmission in the daytime is not possible because of heavy absorption of the skywave in the ionosphere . It was not a blind test ; Marconi knew in advance to listen for a repetitive signal of three clicks , signifying the Morse code letter S . The clicks were reported to have been heard faintly and sporadically . There was no independent confirmation of the reported reception , and the transmissions were difficult to distinguish from atmospheric noise . ( A detailed technical review of Marconi 's early transatlantic work appears in John S. Belrose 's work of 1995 . ) The Poldhu transmitter was a two - stage circuit . </P>
where was the first transatlantic wireless message sent
where was the first transatlantic wireless message sent
Signal Hill in St John 's , Newfoundland
Signal Hill in St John 's , Newfoundland