75 years ago this month, the March 1946 issue of Popular Science showed what you could do with bad tubes. If a tube tested bad for its particular circuit, it was a shame to just throw it away, and you didn’t have to. As pointed out here, unless a tube was completely burnt out, it would probably serve just fine as a rectifier. As shown here, the plate and grids were wired together to form the anode, and the tube could continue for many years serving as a rectifier.
For a snapshot of the cost of living 75 years ago, this ad appeared in the March 15, 1946, issue of the Pittsburgh Press, for McCanns Grocery Store. When comparing pre-1964 prices, one easy rule of thumb is to remember that one dollar equaled one silver dollar, four silver quarters, or ten silver dimes, each equal to about one once of silver. Today, that same ounce of silver is worth about $26, so in today’s money, the 85 cents for three pounds of coffee works out to about $22, or over $7 a pound. The complete sirloin steak dinner sounds like a bargain at $1.35, but that would be the equivalent of about $35 in today’s money.
The eggs sound like a bargain at 49 cents a dozen, but in today’s money, that works out to over a dollar for each individual egg. Of course, the eggs were candled, meaning that you didn’t need to worry about an unpleasant surprise when you cracked it open.
By 1951, TV had become a way of life in major cities, but rural communities lagged. But rural areas were working hard to have the magic of television. We previously explained the herculean efforts which brought TV to Marathon, Ontario. The March 1951 issue of Radio & Television News showed the system put in place in the Panther Valley of Pennsylvania, starting with the town of Lansford, Pennsylvania. The town was 75 miles away from the Philadelphia stations, and had the added problem of having a mountain in the way. In fact, rural residents of Summit Hill, just a mile away from the town, had TV, but the residents of the larger town did not.
The radio dealers in town, eager to be able to start selling TV, decided to take action. A test was run by putting an antenna on the hill and running a coaxial cable into town. The test was successful, and the system was built, as described in the magazine. The system was able to pull in three Philadelphia stations, WPTZ, channel 3, WFIL, channel 6, and WCAU, channel 10.
Fortunately, the cable was allowed on utility poles, and a legal inquiry confirmed that the franchise would not need to be regulated as a public utility. Another legal opinion was obtained from the FCC that no licensing was required. The system was originally envisioned as a nonprofit, but the bankers balked and insisted that the system be operated on a for-profit basis before financing was forthcoming.
One of the great challenges of civil defense planners was alerting the public to an imminent nuclear attack. Sirens could be effective outdoors, but it was unlikely that people indoors would be able to hear them. One possible solution is discussed in the March 1961 issue of Radio-Electronics: NEAR, the National Emergency Alarm Repeater.
Three methods had been considered: telephone lines, power lines, and radio. The technical challenges for using the telephone network for simultaneously alerting the entire population were too difficult to overcome, and not everyone had a phone. Radio was a possibility, but radios were turned off many hours of the day, and especially at night. NEAR took advantage of the power grid. With only a few hundred repeater stations, a 240 Hz signal of about a volt could be superimposed on the line, and the receiver shown here was a clever electromechanical method of picking up that signal and sounding the alarm.
The home NEAR until shown here would be plugged in and forgotten by the homeowner until such time as there was an attack. It included a resonant circuit consisting of a 0.55 uF capacitor and 1 henry coil, with a tuned frequency of 240 Hz. To avoid false alarms, there was a time delay in the form of a 1 RPM motor. If the incoming signal were less than 10 seconds long, then the motor would simply reset and continue listening for a signal. But after 10 seconds, the motor would trip a clapper which used the outside of the device’s case as a sounder. The unit would emit a loud annoying noise which would alert the homeowner to the missiles that were incoming.
These gentlemen 75 years ago were purchasing their power lunch from a coin-operated vending machine capable of dispensing hot dogs, hamburgers, or grilled cheese sandwiches. The picture appeared in the March 1946 issue of Radio Craft, which points out that the machine was only slightly larger than the usual soft drink or cigarette machine, and operated from a standard 117 volt outlet.
The food was heated by radio waves, from “two specially developed high-frequency power oscillator tubes.” In other words, the machine was an early version of the microwave oven. THe engineers toiled long and hard to develop the machine. In particular, the choice of frequency was problematic. Some frequencies would heat the roll but not the frankfurter. Other frequencies would heat the frankfurter but burn the bun. Finally, however, a frequency that was just right was found, and the machine was put into production.
While we recognize this dialectric high frequency heating to be the principle employed by the modern microwave oven, the magazine cautioned that home ovens were not just right around the corner:
It should not be construed from this development that the electronic stove is just around the corner, electronic engineers hasten to explain. The canteen grill and the electronic stove present two different kinds of problems and the accomplishments in the development of the former should not be interpreted as solving the problems yet to be overcome in the field of electronic cooking.
The two in the picture are identified by the magazine as Messrs. Baker and Leverone, first names not given. They are associated with General Electric and Automatic Canteen, the companies responsible for the new machine. Leverone is probably Nathaniel Leverone, the founder of the vending machine company.
When this photo was taken for the March 1941 issue of Радиофронт magazine (Radio Front), the Molotov–Ribbentrop Pact of 1939 was still in effect, and it wasn’t until June 1941 that Hitler decided to invade the Soviet Union.
But if you look carefully at these young comrades, you can see that they know something is wrong. They handed the headphones to their most skilled operator, the young woman at the left, and she is probably pulling in a faint message indicating that the Germans are up to something. Chances are, she tried to warn Stalin, who wouldn’t listen to her. But these comrades knew that they would soon be called upon to defend Mother Russia from the invading horde.
And unfortunately, it’s unlikely that all of these young people lived to see the end of 1945.
These girls are now close to 90 years old, but they undoubtedly had an appreciation for music their entire lives, thanks to their parents’ foresight in buying this model L-678 radio-phono from General Electric. They are shown here having a concert in their very own room thanks to the instrument. They were able to operate the set themselves, and the turntable could accommodate 12 inch records, even with the lid closed.
Their parents were able to find much of the world’s finest music especially arranged for children, allowing them a wonderful opportunity to develop an appreciation for good music. This set retailed for only $39.95. The ad also featured the model L-500 radio, “encased in handsome mahogany plastic cabinet that won the top award in the nation-wide Modern Plastics contest.” Also shown is the portable model JB-410, which the police officer notices and points out that he also has a GE radio in his squad car.
The ad appeared 80 years ago today in the March 10, 1941, issue of Life magazine.
One of the hallmarks of the early postwar years was the lack of housing. There had been a depression followed by a war, which meant that there hadn’t been much new housing construction for a long time. And suddenly, millions of servicemen were returning home from winning a war, getting married, having children, and needing a place to live.
As this March 1946 issue of Popular Science points out, for many, “home” meant a bedroom in someone else’s house. In fact, the number of families doubling up exceeded the entire populations of New York, Chicago, and Philadelphia combined. Some kind of stopgap housing had to be built, and decommissioned military structures were put into service. The federal government made Quonset huts available to cities, universities, and non-profit agencies for use as housing. Those entities were responsible for providing the real estate and building streets and other infrastructure. The also agreed to rent the units on a non-profit basis and dismantle them when the crisis was over.
Photos and stories about one such neighborhood near where I grew up in Minneapolis can be found at this site and this site.
Creed No. 7W/3 Reperforator (1925). Image courtesy of Science Museum Group Collection, © The Board of Trustees of the Science Museum, U.K. released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
No. I.T. Morse Tape Printer (1925). Image courtesy of Science Museum Group Collection, © The Board of Trustees of the Science Museum, U.K., released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
The two devices shown above represent a hundred year old method of automatically decoding International Morse Code. They, along with the sending device, are described in the March 1921 issue of Radio News.
At the sending end, the message is typed on a typewriter-like keyboard and punched onto a paper tape. An example of the tape is shown below. It’s not immediately obvious that the tape contains Morse code, but upon closer observation, it is. A “dot” is indicated by one hole directly above another hole. A “dash” is indicated by two holes that are slanted. Once you see this, the Morse code is obvious. The first word shown here is “the.” The first two holes are slanted. This is a single dash for the letter T. This is followed by four sets of holes, one directly above the other–four dots, for the letter H. Next, there is a single set of vertical holes, another dot for the letter E.
Once this tape is produced, it is sent through another machine which keys the transmitter and sends the Morse signal over the air.
At the receiving station, the two machines shown above are used to receive and print the message. The reperforator (top) connects to the receiver and produces an exact duplicate of the paper tape. Then, the paper tape is fed into the Morse Tape Printer, which prints the message on a paper tape.
The process was known as the Creed Automatic System, named after inventor Frederick G. Creed, an important figure in the development of the teleprinter. At the beginning of the 20th Century, Creed was told my none less than Lord Kelvin that “there is no future in that idea.” Undaunted, he managed to sell twelve machines to the British post office in 1902. The 1921 machine described for use with wireless telegraphy appears to be a variation of that device.
By the late 1920s, the company was producing teleprinter equipment using a variant of the five-bit Baudot code. The company became part of IT&T, and Creed retired from the company in 1930. Among his later projects was the “Seadrome,” a floating airport which could be placed along international air routes. The project is described in a March 1939 article in the Glascow Herald, and was undoubtedly a casualty of both the War and increased aircraft range. The Seadrome is the subject of US Patent 2238974, applied for in February 1939 and granted in April 1941.
The images above are copyrighted and provided courtesy of the Science Museum Group, U.K., where they are on display, and released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
A hundred years ago, if you were located 26 miles across the sea (40 kilometers, for those in leaky old boats) at Avalon, Santa Catalina Island, California, you could enjoy the luxury of telephone service with any telephone in the United States, thanks to the radiotelephone service operated by Pacific Telefone and Telegraph Co., as described in the March 1921 issue of Radio News.
The system consisted of stations KUVX at Avalon and KUXT at Long Beach. A complicating factor was the presence of naval station NZL, also located at Avalon. To avoid interference, the radiotelephone receiving station employed a wave trap to null out NZL’s frequency. The article gives the radiotelephone wavelength of 425 meters (706 kHz). The system was full duplex, meaning that there would be different transmitting and receiving frequencies. Since the 425 meter wavelength is discussed in conjunction with the wave trap on the receiving antenna, it appears that the Long Beach station transmitted on 425 meters, and Avalon transmitted on a different frequency.
The author described an interesting catch for an SWL as part of a test conducted by the Avalon station. He listened in on a conversation from Avalon to the mainland, which was carried by the transcontinental telephone lines to New York, where the call was carried by another radiotelephone station to a ship in the Atlantic. The author reported that the voice was a little distorted, but could be clearly heard throughout the ten minute test.
The Avalon station was powered by a motor generator, and to avoid having to restart the power, the carrier was left on 14 hours a day, with calls to and from local hotels, stores, and residents carried as needed. A licensed radio operator oversaw the transmitter, connected to an eight-wire antenna, and receiver, connected to a loop antenna. A telephone operator put through the calls, presumably with another operator at the Long Beach side of the circuit doing the same.
The system was able to transmit telegraph signals simultaneously with telephone conversations without interference. This was accomplished by “superimposing a high pitched harmonic on the carrier wave.”
A more detailed technical description of the system can be found in the December 1921 Proceedings of the IEEE. You can also find additional references at Wikipedia, which notes that the system was replaced by a submarine cable in 1923, ending the possibility of radio listeners being able to tune in to telephone conversations.
