Seventy-five years ago this month, this ad from Federal encouraged radio dealers to make some extra profit by upgrading their customers’ portable radios. Most such sets operated off batteries as well as standard household current. The radio itself had four tubes, along with an additional rectifier tube for use at home, in this case a 117Z6. The low-voltage tubes came to life almost immediately, but the rectifier took some time to warm up. By replacing it with a selenium rectifier, this problem was solved. And even though selenium rectifiers are famous for their catastrophic failures (which produce malodorous and toxic fumes), they probably lasted longer than the tube, and probably outlasted the radio in most cases.

The age of selenium rectifiers lasted through the 1960’s, when they were replaced by silicon diodes.

The ad appeared in the July 1947 issue of Service magazine.

With radio, as with everything, there’s a right way and a wrong way of doing things. A hundred years ago this month, in the July 1922 issue of Popular Science, Armstrong Perry gives some pointers on how to set up your radio receiving station the right way, and he includes the examples shown above. He concedes that the second station might be highly efficient, but from not planning things out right from the beginning, it is “no ornament to the household.”

A hundred years ago this month, the July 1922 issue of Science and Invention carried the plans for this, which the magazine called the “simplest radio receiver.” The plans had been sent in by Leon Webster, who won $50 in the process, as the third-place winner of the magazine’s radio design competition.

According to Webster, the set could be constructed by a twelve year old boy, and a great deal of pleasure could be obtained. All that was needed was an outside antenna and ground, a tuning coil, condenser, and detector.

The condenser consisted of one from a defunct Model T spark coil, and the detector was a piece of galena or silicon. The coil, as shown here, was homemade on a piece of wood. The set would work with an old telephone receiver, but for better results, a 1000 ohm headphone was the better option.

A hundred years ago this month, the July 1922 issue of Popular Science explains how the Seaman’s Aid Society of New York deals with the problem of medical emergencies at sea, in the form of a radio doctor whose services can span half the Atlantic.

Sixty years ago, this listener was probably listening to a record with the player on the left, but perhaps she is pulling in a broadcast or even shortwave program with the identical unit on the right.

One way or another, she is listening to a Sterephone (note the “e” in the middle rather than an “o”) that she purchased from Hoffman Electronics in Los Angeles for about $80. The one on the left is lying on its side, and in that configuration, it’s a portable record player capable of spinning both 45’s and 33’s. But standing upright, it’s a radio covering the broadcast band and 3.9 to 12 MHz shortwave.

It’s shown here in the July 1962 issue of Electronics Illustrated.  While the magazine doesn’t give the details, it appears to be Sharp’s model BXG-370.  The set was powered by four flashlight batteries, or could run on an optional AC adapter.

This compact 80 meter transmitter designed especially for the novice appeared 70 years ago this month in the July 1952 issue of Radio-Electronics.

The two-tube circuit used a 6AQ5 as a Pierce crystal oscillator, with a 1625 serving as class-C final amplifier. The 1625 is the 12 volt version of the venerable 807 tube, and according to the article, it was possible to buy several of the on the surplus market for the price of one 807. Since a separate 12 volt power supply would be required for that tube, the article suggested using two 6 volt filament transformers in series.

According to the author, good results were had with a 20 foot antenna at 12 feet.

This iconic 70s product was announced 50 years ago this month, in the July 1972 issue of Elementary Electronics.  The design is self-explanatory, as it simply combines an AM transistor radio (with a 9 volt battery inside, no doubt) with a toilet paper dispenser. As the article notes, if you need to absent yourself from the living room during a program, you’ll still be able to tune in. And the device also “enhances bathroom privacy,” which I assume means that you can turn up the volume to cover up any embarrassing noises.

I saw these radios advertised, but since I wasn’t in charge of purchasing bathroom fixtures for my household, I was never able to take advantage of this good idea. And shockingly, it appears that they’re not made any more. The closest I’ve been able to find are the shower radios shown below. I’m sure these are much better radios than the 1972 version, and the main feature is their waterproof construction. But I’d still like one of the 1972 versions. If you order one of the sets below, since you’re placing an Amazon order anyway, you may as well order the big package of toilet paper, just in case there’s another supply chain problem. But unfortunately, you’ll need to use your existing holder.

The product was offered by Mason’s Gifts of El Paso Texas.  Whoever Mason was, they were quite entrepreneurial.  The address shown is a residential address, so apparently Mason got their hands on a bunch of these radios, and prevailed upon the magazine to offer this free advertising.

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Shown here 70 years ago on the cover of Radio News, July 1952, is a way for the sound man to make some extra income, namely, the rental of small public address systems. According to the accompanying article, there was a time when the carnival barker depended on being leather-lunged, relying on the volume of his voice. But with a small PA system, voice volume was no longer important, and any desired crowd could be covered with little effort, even with high noise levels.

The article pointed out that “personnel using equipment of this type are non-technical, and consequently the equipment must be simple to operate and have a minimum of controls.” And the gear must be capable of rough handling, simple, and light weight.

The model shown here was model E-10 from the Newcomb Audio Products Company, and both the microphone and a phono input were included. A carrying case with self-contained speaker was available. The microphone shown here, a chest type, was the American Microphone Company model D4G.