This young man is pulling in the shortwaves courtesy of an extremly simple circuit which appeared in the Spring 1962 issue of Radio-TV Experimenter.

The radio consisted of a crystal set, feeding into an audio amplifier module. The amplifiers were available from Lafayette and other retailers, and drove a speaker. The receiver itself consisted of just a germanium diode, along with coil and capacitor. The coil is wound on a ferrite core, and is seen protruding from the top of the set.

Despite the simplicity, the author was able to pull in signals from the strong European shortwave broadcasters with only a short antenna and ground. The set tuned about 3.5 to 7 MHz.

Eighty years ago this month, the May 1942 issue of Radio Craft showed how to put together this simple one-tube receiver. Being a battery set, there was no need to worry about hum, and the batteries were inexpensive. The B+ voltage was only 7.5 volts, so even with a large dry cell for the filaments, the battery cost was only 58 cents.

The set used a 1S4 tube as regenerative detector. It had two bands, which were switched by moving an alligator clip on the antenna coil. The overall tuning range was 480 kHz through 2.5 MHz, meaning that it covered the entire broadcast band, plus a little bit above and below. Thus, the set could also be used to pull in ships as well as police broadcasts.

Seventy-five years ago this month, the April 1947 issue of Radio News, showed how to construct this three-tube (plus rectifier) regenerative receiver for the broadcast band and shortwave. Five plug-in coils covered the standard broadcast band, as well as the 160, 80, 40, and 20 meter ham bands, as well as adjoining shortwave broadcast frequencies.

The article noted that since the war ended, interest in shortwave had reached a new high, and this set provided a simple way to catch these signals. Due to scarcity of power transformers, and AC-DC design was used, with a 35Z5GT rectifier.

The radio itself consisted of a 12SJ7 regenerative detector, 12J5 first audio stage, and 50L6GT output, which provided loudspeaker volume to a dynamic speaker.

Among the youth of America, headphones are more than a means of delivering music. They are now a status symbol, to the point where there have been murders over popular brands of headphones. Here are some popular brands, and note the price tags:

Sixty years ago, this young man was a trendsetter, and we can only conclude that he was the coolest kid in class, since he was the first to have a pair of stereo headphones. Since there was no such thing on the market, he made his own. In addition to undoubtedly being a chick magnet, they probably sounded better than the expensive ones today. The plans were contained in the Spring 1962 issue of Radio-TV Experimenter.

The speakers were actually 3-inch replacement speakers for a transistor radio, but since they were driven at such a low level, there was very little distortion. And the response could be adjusted by means of a cardboard baffle. Bass notes went through the cardboard just fine, but to adjust the response at the high end of the range, the size of the hole could be varied. The stylish design was made with plastic cups, cardboard, foam rubber, and tempered brass wire. It was all held together with a little bit of contact cement.

Some links on this site are affiliate links, meaning that this site earns a small commission if you make a purchase after clicking the link.

Eighty-five years ago this month, the April 1937 issue of Radio Today contained this Philco ad reminding dealers of the profits to be made selling intercom systems, specifically the Philco Phone.

A set of two stations sold for $49.50, and additional stations were available for $10 each. The ad noted that even small offices, such as one or two doctors or dentists and a receptionist, could benefit from the set. And businesses such as garages, restaurants, and theaters could put themto good use.

And it was an easy sale for the dealer, with no trade-ins, no expensive installation, or service worries.

And there was even an untouched market in the “better homes” in the community.

The plans for this handsome little one-tube receiver appeared 75 years ago this month in the April 1947 issue of Radio News.

The magazine noted that this simple circuit was one of the most useful pieces of equipment you can build. Obviously, it could be used as an extra receiver, but could also be put to other uses as well.

One half of the 1G6-GT tube served as regenerative detector, with the other half serving as audio amplifier to drive a pair of magnetic headphones. (The article points out that crystal earphones wouldn’t work with this circuit.) It is mounted on a 5 by 7 inch plywood base, with a front panel made of sheet steel. With four plug-in coils, the set would tune from below the broadcast band up to 18 MHz.

A hundred years ago this month, this receiver was the winner of first prize in a contest run by Science and Invention magazine, and appeared in the April 1922 issue. The set was said to be adequate for pulling in stations 15-20 miles away. The only tools required to construct it were a knife and small nail, it could be built in about 30 minutes, and the cost was only $30, including headphone and antenna. The phone receiver was the most expensive component at about $2, and the cost of the set itself was only 21-1/2 cents.

With a 25 foot antenna in New York, the set was said to pull in stations WDY and WJZ. In fact, the author reported that on several occasions, the phone could be held about six inches from the ear with music and voices clearly distinguishable.

The author, and winner of the $100 first prize was James Leo McLaughlin. You can see some more of his receivers at this link.

All of the parts are readily available, if you don’t have them around the house already. The chassis is a 4-inch diameter cardboard container. You can probably ask a friendly restaurant to give you one of their takeout containers, or you can use the time-honored crystal set chassis, namely, an oatmeal container.  The terminals are brass paper fasteners and paper clips.  You’ll need some 26 gauge enamel wire for the coil, and wire of any size for the antenna. In lieu of the headphone, it’s easiest to use a high-impedance crystal earphone.

Finally, the article calls for a piece of silicon or galena for the detector. The gift shops of most science museums have an assortment of minerals for sale, galena being one of them. Or, like everything else, you can order it from Amazon.

Some links on this site are affiliate links, meaning this site earns a small commission if you make a purchase after clicking the link.