This post-war foxhole radio replica isn’t dated but it has been around for a few decades at least. Photographed in 2006 at the Museum at Mountain Home, Quillen College of Medicine, East Tennessee State University.
Mountain Home foxhole radio
Razor blades tested in foxhole radios
These are the blades I tested as detectors for foxhole radios. These are all in black and white in the book so here they are presented in glorious color.
Captions are from the book.
Previous: WWII era Gillette blades
WWII era Gillette blades
More blades that appear in black and white in the book, this time from Gillette. Caption is from the book.
The next post will cover all of the blades I tested in foxhole radios.
Previous: More WWII era blades Next: Blades tested in foxhole radios
WWII era razor blades
Here are some of the WWII era razor blades that appear in black and white in the book. The captions are from the book.
The post immediately following this one will cover Gillette wartime blades.
Next: WWII Gillette blades
Mystery soldier
This is Photograph 111-SC-282168 U. S. Fifth Army Mobile Unit Programs Can Be Heard over Razor Blade Sets. 1945. Records of the Office of the Chief Signal Officer, Record Group 111. National Archives at College Park, College Park, Maryland. It is by far the best known photograph of a soldier with a foxhole radio at Anzio. It was taken for YANK magazine but never ran.
The other photos in series with this one include the names of the subjects. But not this one. The note with the negative only gives the title. So far this soldier remains anonymous. I would prefer to include his name in the book, naturally, so if anyone recognizes him please let me know!
Emergency crystal detector
Razor blades were occasionally used to make radio detectors even before the invention of the foxhole radio, though not in the same way. This one, from the June 1925 issue of Radio News, uses two blades mounted upright – not the safest configuration – which are straddled by a chunk of “coke, carborundum or pyrites”. The contact between the blades and the mineral function as a demodulator of radio waves.
It isn’t exactly a foxhole radio detector, but it does show the same sort of improvisation that would lead to the razor-blade-and-pin detector. The Radio News detector more closely resembles a “microphone” detector, which either used a piece of steel – like a sewing needle – straddling two sharpened carbon edges, or else a small piece of carbon straddling steel edges. It is called the microphone detector because it resembles the microphones developed by David Edward Hughes in the 1870s. Hughes also discovered that his microphones could detect electromagnetic waves, though his findings were initially dismissed. The microphone as a detector of radio waves was more common in the early 1900s than the 1920s.
A potato by any other name
Researching foxhole radios and early radio wave detectors uncovers a lot of clever and strange equipment improvised by early radio amateurs. Like this radio wave detector made from a potato from the July 1915 issue of The Electrical Experimenter, invented by Milton Rochkind. As he explains it:
While putting up an aerial in my yard (80 feet long and 60 feet high) recently I tried to receive wireless messages. I took a potato and placed it on a box. Then I took two sewing needles. I took one needle and stuck it into one side of the potato. I then connected the second needle with one pole of the receiver and stuck it in the other end of the potato. I took the ground wire and connected it with the other end of the pole of the receiver, and when this was completed I was able to receive many messages just as clearly as from a detector.
The editor assumed the potato was acting like an electrolytic detector, a common detector of the era. I tried repeating the experiment but never got a signal. If anyone reading this manages to make a working radio from a potato I would love to hear about it.
There were an amazing variety of radio wave detectors in the pre-crystal and vacuum tube days. They are well covered in Vivian J. Phillips’ Early Radio Wave Detectors. Stevenage, Hertfordshire, England: P. Peregrinus in association with the Science Museum, London, 1980.
I’m ready for my close-up
If you’ve ever wondered what a razor blade looks like magnified 500 times, this is it. I was having it analyzed to see if there was any surface chemistry that would make it a good detector for radio waves. This is a WWII era “blue” blade. Despite popular folklore to the contrary, there was no selenium present. SEM image by Houston Electron Microscopy, Inc.
Here’s the same blade at 75x.
The iron oxide is likely magnetite, which can act as a semiconductor. It is a thin enough layer that it allows some light to pass through, causing thin-film interference, similar to the surface of a soap bubble. This accounts for the subtle blue color of the blade.
Chenoa, Illinois
Last week I was fortunate enough to pass through the City of Chenoa, Illinois (on the way to Chicago) on a Tuesday, one of the two days (the other is Saturday) that the Chenoa Historical Museum is open. Chenoa was home to George B. Ferree, who built a “pre-foxhole” foxhole radio from spare parts during the First World War. I had worked with the Museum before – see my previous post about the late Evy Reis – but wanted to see if they had found anything else.
We arrived a while before they opened and walked around the square a while. It is a classic small American town.
There wasn’t much activity other than a guy on his riding lawnmower down the street.
The museum opened at 10:00. It was packed with documents, photos, newspapers, and all sorts of local artifacts. They have done an excellent job collecting objects significant to the area. They had a file folder on Ferree, a shadow box with some of his metals and WWI documents, and his WWI campaign hat.
They also had an interesting little stone turtle Ferree presumably carved during the Second World War, which he also served in. It was found in a garage sale in Arizona and mailed to the historical society. How it ended up in Arizona is unknown.
I didn’t find much new information about Ferree but it was nice seeing the town and artifacts. The museum will be contacting me if anything else turns up so stay tuned…
A mystery
This message was posted in the Yahoo group “Loop Antenna News and Information Forum” back in 2007:
“Hue, as a project in my AIT class (Basic Receivers) back in the early 1980’s, I had the students gather the materials and build a foxhole radio during a weekend field training exercise. It took about two hours, and they were encouraged to improve on the design after successfully completing it. The model I used was handed down to me by an Uncle who served in the Marines through Guadalcanal, New Briton, and Peleliu, after which he transferred to the U.S. Navy for Okinawa. The first one he made while on Guadalcanal, the wire and headphones stolen from a Bell Aircobra. He told me the plans came by way of scuttle-butt, I.E. one guy would show the next. Apparently they were popular enough that aircraft headsets had to be locked up rather than left in the cockpit. He said he made several on Guadalcanal for buddies, and on New Briton, and one on Peleliu. All were sensitive enough to listen to Tokyo Rose at night, even on Guadalcanal. The plans he turned over to me were specific and detailed, down to which model number headphones were suitable. At the time I taught, Blued razor blades were the hardest item to procure. Luckily, a local small-town pharmacy kept a stock of blued razor blades. I don’t think they are available any more. The original varied in several respects from the garden variety seen on the internet in that it was designed to receive 4-10 MHz rather than the Broadcast band, among other things. I suppose they were also used in Europe, but my Uncle never met a Veteran who had used one in the European Theater, though he met many who had used it in the Pacific.”
This is one of the few references I’ve seen to a foxhole radio built in the Pacific theater, and, I believe, the only one I’ve seen built by a Marine. So naturally I’d like to find the author of this post to interview him.
Unfortunately he seems to have disappeared.
He posted under the handle mhatlau, and his real name is Mark Huss. He would be around 60 now and works in the electronics industry. If by some slim chance anyone who is reading this knows Mr. Huss please let him know I would love to interview him!