From this spot Marconi beamed the first radio transmission across water, to Flatholm Island, three and a half miles away in the Bristol Channel. Barry society members waited on the island yesterday for the signal, a letter V sent in Morse code, during a re-enactment of Marconi's breakthrough on 13 May 1897.
The society's chairman, Glyn Jones, said: "This is a little bit of history that has been totally ignored because it happened in Wales ... We have built a receiver exactly like Marconi's ... His achievement was absolutely mind-boggling and it took three days before they got it right because they had no idea which frequency they were using. They couldn't wave flags or talk to the guys on Flatholm Island, who were just sitting there fiddling with the receiver. Then ... Marconi moved his transmitter down to the beach from the clifftop and added more wire to his aerial - quite by accident this lowered the frequency and, Eureka!, they connected.
"The people on Flatholm were so cold and cheesed off after three days sitting on the beach that one of their first messages back was 'Go to Hell'. But four-fifths of our planet is water and Marconi allowed us to talk to the world - that's why I get so buzzed up ... Without radio you couldn't use those yuppy phones people now take for granted and the 730 people rescued when the Titanic sent out the first SOS message would simply have died."
In 1895 Marconi made the first radio transmission in his garden at the Villa Grifone, near Bologna. But an inability to send signals across water baffled scientists.
Finally, he went to Wales to try to solve the problem before Queen Victoria's chief engineer, Sir William Preece, who came from Caernarvon and was aware of the benefits radio communications would bring the Royal Navy.
For yesterday's re-enactment the Barry radio buffs used an aerial suspended from a helium-filled weather balloon flying 200 feet above Lavernock Point.
Because the balloon was on the flight-path to Cardiff Airport and a nearby RAF base the Civil Aviation Authority was required to give special permission and warn aircraft to stay away.
Marconi's assistant, George Kemp, attached the aerial on Flatholm Island to a kite but the Barry group cheated slightly and fixed theirs to the lighthouse. Italy's vice-consul to Wales, Dominic Casetta, made the boat journey to Flatholm to unveil a sculpture, shaped like a thunderbolt, to mark the centenary celebrations.
In the island's disused army barracks members of the Barry group were taking calls from radio hams from all over the globe. "It's the first time the GB100FI call sign has been used and there is one hell of a pile- up," said Bob Walsh, an Internet publisher. "Its taken years to plan this event and the mood is one of elation."Reuse content