A radioscientist's reaction to Marconi's first transatlantic wireless experiment-revisited

On 12 December 1901 signals from a high power spark transmitter located at Poldhu, Cornwall, were reported to have been heard by Marconi and his assistant George Kemp at a receiving site on Signal Hill near St. John's, Newfoundland. For this reception experiment, Marconi used a kite supported wire aerial, an untuned receiver, a detector of uncertain performance and a telephone receiver. The signals, if heard, would have traveled a distance of 3500 kilometres. Even at the time of the experiment there were those who said, indeed there are some who still say, that he misled himself and the world into believing that atmospheric noise crackling was in fact the Morse code letter "S". A little later, in February 1902, when Marconi was returning to North America on the SS Philadelphia, using a tuned ship-borne antenna, he received signals using his filings coherer from the same sender up to distances of 1120 km by day and 2500 km by night. Even these distances are rather remarkable considering the receiving apparatus he used. This paper revisits that first transatlantic experiment and concludes that it is difficult to believe that signals could have been heard on Signal Hill.