Technology History | Poldhu, Cornwall — The Aerials Had Blown Down Three Months Earlier

The field behind the museum is where the aerial stood that sent three dots at the Atlantic on 12 December 1901.

It was not the aerial Marconi had planned to use. A ring of twenty masts went up here in 1900 and a September 1901 gale flattened them, so what actually transmitted was a temporary fan aerial slung between two masts of 160 feet.

The pre-arranged signal was the letter S in Morse, three dots, sent over and over at agreed hours while a man in Newfoundland listened.

Marconi's own account of the result is careful in a way the retellings are not. Signals came at 12.30, at 1.10 and at 2.20, and they were heard on the telephone receiver but not on the ordinary recorder.

Nothing was written down by a machine. That is the whole of the case against him, and it was made loudly at the time, because the only other person listening was George Kemp, who worked for him.

Two months later Poldhu sent signals strong enough to drive a Morse inker in front of witnesses, which is the confirmation the December claim never had.

Marconi also did not know why it had worked. The idea that radio waves bounce off a charged layer in the upper atmosphere was proposed the following year, and the physics that carried his dots over the curve of the earth was not understood when he claimed them.

The station here was rebuilt in 1902 with four lattice masts of 215 feet and worked for years afterwards, and none of it stands.

What is on the cliff now is grass, a small white memorial obelisk, a mast used by the amateur radio club, and the Marconi Centre museum next to the field.

The obelisk is the pale shape at the right-hand edge of the photograph.

Photo: David Smith, CC BY-SA 2.0, via Geograph and Wikimedia Commons