Orca Members In the News

Reinventing Spark Gap Radio

May 2024 -- A new article by Orca member Guy Immega, VA7GI, will be published by TCA (The Canadian Amateur) magazine. "Reinventing Spark Gap Radio" was inspired by a visit to Signal Hill in St. Johns, Newfoundland, the site of Marconi's transatlantic experiment in 1901.

Guy notes that "most of the pioneering work on radio done in the early 1900s is now obscure or lost, with only dusty remnants in museums. No living hams have ever used a spark gap transmitter. Marconi kept details of his technology secret - his radios saved 710 lives on the Titanic in 1912. Spark gap transmitters were prohibited by international law in 1934, ending an era by fiat. From then on, CW (continuous wave) signals ruled the airwaves."

"Adding to the romance are mysteries," says Guy. "Marconi had no idea why radio signals bent around the curvature of the Earth. Even today, there is no consensus on how the coherer detector works. Practical details generating sparks and using a coherer to receive Morse code needed to be reinvented. Unlike Marconi, I wanted extreme QRP (the average power of the spark gap is about 40mW) with a maximum range of about 25 feet (to minimize interference during short tests)."

Watch for Reinventing Spark Gap Radio in an upcoming edition of TCA (2024)