1944 · Razor-Blade Crystal Receiver · Work 813 of 1,871
A homemade radio receiver of 1944 on a crate of raw wood in a shelter dug into sandy ground on the Italian coast, a small wooden board ten centimetres square, on it a block of wood wound with one hundred and seventy turns of copper wire, a thin flat rectangular piece of dark blue steel held down by a thumbtack, a safety pin with a short pencil lead tied to its point resting on the blue steel, bent paper clips as terminals, a thin wire leading up to a branch, a black Bakelite headset on a cloth cord, an olive wool jacket seen from behind, rainwater on the ground, grey daylight.
What it was used for
On the Anzio beachhead in Italy in 1944, soldiers built receivers from a razor blade as rectifier, a pencil lead or a safety pin as the point, a coil, an aerial and earphones; the earphones sat between the pin and the grounded side of the coil. QST of July 1944 reports, on the word of Toivo Kujanpaa, a licensed radio amateur stationed there, that several radio men on the beachhead rigged up such a set. Time of 17 July 1944 names Lieutenant M. L. Rupert as one of hundreds of US infantrymen who built such a set.
What was new
What is characteristic is that nothing was invented here but something replaced: with no valve, no battery and no issued component, the blade and a carbon or steel point formed the detector of what QST calls a field version of a crystal set. The New York Times of 25 June 1944 (Jack Gould) attributes the pencil-lead idea to O. B. Hanson of NBC. The barb: what came in was the enemy. QST names a jive programme and German propaganda from an Axis station in Rome; a letter in QST of October 1944 (Justin Garton) reports that the beachhead received Rome by day and propaganda from Berlin by night.
What the sources leave open: Only a compilation was opened (onetuberadio.com), citing QST of July, August and October 1944, the New York Times of 25 June 1944 and Time of 17 July 1944; those original issues were not themselves opened. The origin of the blades given there (Marlin Firearms) is therefore omitted. There is no unit figure, only Time's "hundreds".