Transcription Mystery Disc # 57

This one came with the disc from "Studio d'Enrigistrement."It has even less information and in it's own way poses a greater mystery. It's in somewhat better condition but is engineered differently making it not possible to date one with the other with any certainty.

This disc is one-sided, and playback is center start. The blank is made by Radiodiffusion Francais. There are front and rear labels but both are damaged and at least the remaining label is blank. the recording is wholly in English and the presumably American interviewer Beth is asking Danielle about acting. Danielle is from Paris and the interview gives the impression she is not yet very accomplished.
The audio is very good, but there were no clues in the content. Only the maimed label tells me anything. Radiodiffusion Française (RDF) was the French public radio and Television Broadcasting from 1945 to 1949. After 1949 it was called "Radiodiffusion-Télévision Française" (RTF.) This makes the manufacture date of the blank to that 4-year time frame. But as well all know a blank can be recorded on decades after it's made. But generally the wear and palmitic discoloration makes me believe it's as old as it seems.

Radioman 2nd Class

"CAUTION! NOT TO BE ENTRUSTED TO THE CARE OF ENLISTED MEN!"

It sounded subversive, a peek behind a curtain of some kind. So I ferreted it home, and over many days, scanned it one page at a time into a PDF. It was the 1940 edition, so I have no doubt that in fact enlisted men can freely read this completely out of date 69 -year-old radio navigation text.

Radioman 2c is a designation under the artificer's branch. It that sets pay grade, an insignia, and indicates a set of positions that person may hold. Like most military positions to move up in rank one must pass a test. This is the instructors exam with answers for the Radioman 2c exam. There's a little more information here.

Radioman was a rating for United States Navy and United States Coast Guard enlisted personnel, specializing in communications technology. The rating was created in 1921 and was used continually until it was merged with Data Processing Technician into the Information Systems Technician. The Radioman was not just a DJ, what they called a Broadcast Operator, but also teletype repairmen, Crypto operators, supervisors, Distro Operators and every other job that fell under the qualification.

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Radio for Navigation (pre tomtom)

Throughout history men have gotten lost on long trips, flubbed their ability to use maps and refused to ask for directions. About 100 years ago it got harder to get lost.

I see this as developing in three major steps
1. radio wave detection
2. first attempt at a navigable beacon
3. first large scale implementation attempt.
In 1894 British physicist Sir Oliver Lodge demonstrated the possibility of signaling using radio waves. He did this with a device called a coherer [pic below], a vacuum tube filled with iron filings. He did not invent this device. In fact the Coherer had been invented 10 years earlier by Temistocle Calzecchi-Onesti. The coherer had gone through revisions in the hands of Edouard Branly and Alexander Popov. [Popov actually invented a radio communication system based on the coherer, is yet another candidate for inventor of radio]

The Coherer was a radio-wave detector and the heart of the early radiotelegraph receiver. It functioned as a rough gauge of resistance. I So now we could measure the radio wave, and thus distance from the transmitter by signal stregnth ... a fixed point. [later revisions to sensitivity allowed this to decode the first dots and dashes]
Around 1900, only 6 years later, Tesla opens the Wardenclyffe Tower facility and advertises it's services. He intended for the massive Wardenclyffe tower facility to be a radio beacon for navigation, and even time synchronization. But by 1905 Tesla had to shut it down. It was sold for $20 grand in debts.
In WWII radio navigation matures into practical use. The need to blow more people up more efficiently begets the need to pinpoint aircraft position. RDF is born. The Radio Direction Finder works by pointing a directional antenna in "various directions" and then listening for the direction in which the signal from a known station comes through most strongly. (this skips the triangulation needed to make an estimate with a coherer.) In WWII pictures of aircraft the RDF antennas are easy to spot on German World War II aircraft, as wire loops under the rear section of the fuselage. In Allied aircraft it was enclosed in a small teardrop-shaped fairing.
RDF using aircraft tuned into brodcasts of morse code letters. This technique is still used today by commercial aircraft. Most modern detectors can also tune in any commercial radio stations, which is particularly useful due to their high power and location near major cities.