Newsletter 2012

Marconi spark transmitters

From Richard Shaw, 24 June 2011

Further to Roman Buja’s enquiry regarding the Marconi Spark Transmitter Type Y and Chris Gardiner’s reply (MVA Newsletter No. 13, January 2011), although I have no information regarding that type of transmitter, I should perhaps point out that Mr Gardiner’s statement that “spark transmitters … did not exist as operational units by 1920” is slightly misleading.

In fact, the Marconi ¼ kW Quench Gap (QG) Transmitter Type 341 was certainly in service well into the Second World War as a standard emergency transmitter aboard many merchant ships, and formed part of the syllabus for the PMG ‘Special’ Certificate of Proficiency in Wireless Telegraphy.

Mounted on a wooden base, the works were totally open to view from above, being protected from damage by a handsome brass-barred cage on each side. (What ‘elf and Safety would say about it today can scarcely be imagined!) I enclose a photocopy of the circuit diagram of a typical Emergency Installation from my 1941 Wireless College notebook, now unfortunately spoiled by rust stains from the staples.

Secondly, in Peter Wright’s 1987 best seller, Spycatcher, he recalls several fascinating tales of his and his father’s association with the Marconi Company.

For example, Chapter 2 starts, “My father joined the Marconi Company from university in 1912 and began work as an engineer on an improved method of detecting radio signals. Together with Captain HJ Round he succeeded in developing a vacuum receiver which made the interception of long-range communications possible for the first time. Two days before World War I began he was working with these receivers in the old Marconi Laboratory at Hall Street, Chelmsford, when he realized he was picking up German naval signals. He took the first batch to the Marconi works manager, Andrew Gray, who was a personal friend of Captain Reggie Hall, the Head of the Naval Intelligence Department.”

The early chapters contain several fascinating references to early work by the company, such as his account of working at nights and weekends at a “new, secure laboratory in a field at Great Baddow” (a Nissen hut), to unravel the secret of a Russian eavesdropping device found concealed in the American Ambassador’s office in Moscow.

You may recall that the government made desperate efforts to stop the book being published; but as Wright and his wife had emigrated to Tasmania, he was able to get it published by Heinemann in Australia. It may be that they, or his co-author, Paul Greengrass, still have notes made during this time – anecdotes that, for whatever reason, never found their way into the book – and which could throw more interesting light on these early years in the Company’s history if they could be unearthed. Perhaps a Veteran in Australia could make inquiries?