Category Archives: Radio history

1944 Tape-Operated Code Sender

1944FebPM1944FebPM2The gentleman shown here is practicing copying Morse Code that the woman is literally cranking out for him, thanks to this automated code sender from the February 1944 issue of Popular Mechanics.

Today, it’s a relatively trivial matter for a computer to generate code, such as with this online code generator. But 75 years ago, saving a message for later replay probably involved paper tape. This machine allowed you to play such tapes, using a contact made of distributor points from a car. The tape could be prepared (using ticker tape) with a hole punch, or you could use commercially available tapes (probably Instructograph tapes).

The device could be powered with a crank, or with a sewing machine motor controlled by a rheostat.



KFAB Lincoln, NE, 1944

1944Jan31BCSeventy five years ago today, the January 31 issue of Broadcasting carried this ad for KFAB, then in Lincoln, Nebraska, and on 780 kHz.  As we noted earlier, KFAB shared the frequency with fellow CBS affiliate WBBM in Chicago, and the two stations coordinated their signals.

The station made the move to Omaha and to its present frequency of 1110 kHz in 1948.  The move allowed both WBBM and KFAB to boost their transmitter power to 50 kW.



1939 Admiral Aeroscope

1939JanRadioTodayThe handsome receiver shown here is the Admiral Aeroscope model 163-5L.  The fine print reveals that the price of the set shown is actually $15.95.  The set was available in three different Plaskon cabinets:  Walnut (model 161-5L) for $9.95, Ivory (model 162-5L) for $13.95, and Onyx (model 163-5L) for $15.95.

The set was billed as 6 tube (including ballast), meaning that it was a 5-tube (“All American Five”) receiver with an additional “tube” containing a dropping resistor.

The ad appeared 80 years ago this month in the January 1939 issue of Radio Today.



1969 Radio Shack “P-Box” Shortwave Kit

1969JanEEFifty years ago this month, the January-February 1969 issue of Elementary Electronics reviewed the Science Fair “P-Box” shortwave receiver.  The three-transistor set used one transistor as regenerative detector, with the remaining two serving as audio amplifiers.  With interchangeable coils, the set covered 3-40 MHz.

I had one of these, and even though it made sound, I never did pull in any shortwave stations. I did manage to get some overload from local FM stations. I suspect if I had been more patient with the regeneration control, I actually would have received some shortwave.



1925 Multi-Tool

1925JanExperimenterHere’s the 1925 version of the Swiss Army knife, especially for radio fans. This 16=in-one tool was advertised in the 1925 issue of The Experimenter, and was sold by the Radio Specialty Company of New York.

A similar idea, in credit card size for easy wallet storage, but with a different selection of tools, is shown here and available at Amazon.



1924 Trego Baby Grand

TregoBabyGrandIn 1924, the Trego Radio Mfg. Co., 1427 Chestnut St., Kansas City, MO, offered this one-tube set, the “Baby Grand” in their catalog.  For $28.75, you got everything you needed, including the tube, batteries, and even antenna and ground wire. The batteries even came installed inside the set, which was said to have a range of 500 to 1000 miles.

The set was also available without tube, batteries, or other accessories, for $15.35.



1959 One Tube FM Portable

1959JanPESixty years ago this month, the January 1959 issue of Popular Electronics showed how to put together this portable one tube FM receiver. The set used a single 1AG4 tube as a superregenerative detector, and used a penlite cell for the filament and two 22.5 volt batteries to supply the B+.

Even though a superregenerative receiver is best suited for AM signals, it does an excellent job on FM with slope detection. The tendency of the set to radiate was put to advantage in the instructions for calibrating the dial. The article suggested using a second receiver, tuning it to 88, and then tuning the portable until the rushing sound was heard on the other receiver.

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1959 Crystal Set

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The young man shown here (quite possibly the son of article author T.A. Blanchard) is probably getting ready to collect his first Social Security check. But sixty years ago, he was shown in the 1959 issue of Radio-TV Experimenter operating this simple crystal set.

The antenna and ground leads are soldered to “frictioned” paper clips, which could be connected to a convenient antenna such as the dial stop on a telephone. Tuning was accomplished with the adjustable ferrite antenna coil. The set would not tune the entire broadcast band, but the article included values for the fixed capacitor to cover various portions.1959RadioTVexpSchem



1949 Custom Installation

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This handsome home entertainment installation appeared on the cover of Radio Television News 70 years ago this month, January 1949. While it appears to be a single console, it’s actually a custom installation of discrete components, a television, radio, and record player.

The issue provided guidance for dealers looking to move into this field, and suggested that thoughtful design and installation of such custom designs could be a lucrative proposition.



1944 Crystal Sets With Homemade Parts

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Wartime parts shortages were undoubtedly the inspiration for these two crystal sets from the January 1944 issue of Popular Mechanics. While commercial parts could be used, from the junk box, salvaged from an old radio, or from a mail-order house, the article showed how to make most of the parts. The article notes that the newcomer needed only a good set of headphones to build either set from scratch.

1944JanPMcapacitorThe first set, shown above, omitted a variable capacitor, as it used a variometer for tuning. It did require one fixed capacitor, but the article shows how to make one using copper foil and either mica or wax paper.

A commercial fixed crystal can be used, but the article also shows how to make one. The crystal is mounted inside an old tube base and sealed with wax. The use of an old 4-prong tube socket meant that a commercial fixed crystal could be substituted at a later time.

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The second set, shown above, featured a variable capacitor for tuning, which was constructed “book” style. The top plate, made of spring brass, was hinged and moved up and down from the lower plate.

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The sets were said to have a range of about 25 miles.

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