Monthly Archives: October 2016

Happy Halloween!

Happy Halloween from OneTubeRadio.com!

The illustration above is from a Halloween a century ago, taken from the 1916 book “Handicraft for Handy Girls: Practical Plans for Work and Play.” The book describes how to construct this “Witch’s wigwam,” complete with caldron, harvest moon, and make-believe fire.

Kids a century ago were thoroughly modern, so the make-believe fire is electrical, consisting of an electric light beneath a few sticks, with a piece of red tissue paper covering the lamp. The moonlight effect is created by placing another electric lamp behind the moon. The book suggests that the room can be lighted entirely by the moonlight and firelight thus produced.

1916 One Mile Transmitter

A hundred years ago, the October 1916 issue of Popular Science gave detailed instructions for constructing a transmitter capable of sending one mile, the diagram of which is shown above. The set was powered by nine volts, consisting of twelve dry cells wired in series-parallel.

When the modern reader looks at a diagram such as this one, it’s not readily apparent how the set could actually work, since one critical part of the transmitting coil is not shown. The article noted that plans for constructing the coil were available in many books, but recommended that it was simpler and cheaper to simply buy one. It suggested an automotive spark coil, which could be obtained from a garage or electrician at nominal price. The article noted that even a new coil would cost no more than three or four dollars.

Such a coil is actually a transformer, and the primary is wired at the factory in series with an normally-closed interrupter. When the coil is energized by the nine volts, it creates a magnetic field, which opens the interrupter contact. This breaks the circuit, and the coil de-energizes, which results in the interrupter closing again, allowing the process to repeat. The net result is that an interrupted direct current is produced in the primary, and this induces an alternating current in the secondary. The secondary is a large enough voltage to make a one-inch spark in the attached spark gap.

The spark gap, shown here, is constructed from two pieces of zinc mounted on a hardwood base boiled in paraffin. The key could be an ordinary telegraph key, which sold for about 75 cents, or could be homemade.

The article stressed that the loading coil, shown here, was required to keep the transmitter on the correct wavelength, below 200 meters, to comply with federal law. It was constructed between two square boards, about 12 by 12 inches. FInally, an aerial of no more than 75 feet was required, and the article contained pointers for its installation as well.

Finally, the article described operation of the set:

Whenever the key is pressed, if the set is properly connected and adjusted, a bright, snappy, singing spark will jump across the gap. Each spark starts a train of high frequency currents oscillating back and forth in the aerial wires, and a train of electromagnetic waves is radiated into space. A suitable wireless receiver located where a portion of these radiated waves will reach it, will pick up some of their energy and produce from it a sound which indicates the dot-and-dash buzzes of a Morse signal.

Winston Churchill: Never Give In

On this date 75 years ago, October 29, 1941, Winston Churchill gave his “Never Give In” speech.

Never give in, never give in, never, never, never-in nothing, great or small, large or petty – never give in except to convictions of honour and good sense. Never yield to force; never yield to the apparently overwhelming might of the enemy.

WW2 CBS Broadcasts

One of the fascinating parts of collecting old radios is pondering the kinds of programs they pulled in over the years. Chances are, the radio was used to listen to countless hours of news, music, entertainment, and sports. They were a witness to history, but the frustration is that we can no longer listen to the programs that were broadcast. Programs generally weren’t recorded, and most of the live programs that were broadcast were lost.

Fortunately, there are exceptions, although most of them were the result of accidental preservation. One example is documented in this news story from KIRO in Seattle:

KIRO Radio accidentally saves American history

Even though it was contrary to network policy, KIRO made a practice of recording CBS network news on 16 inch discs, so that they could be replayed at a more convenient hour for West Coast listeners. Fortunately, someone rescued these discs when they were to be discarded, and they are now in the collection of the University of Washington. They are gradually being digitized, and many are available at this link. The first one in that collection, for example, is a broadcast from September 1, 1939, and include a report from London of the declaration of war.

No Serviceman Would Sneer at an Extra $5: 1936

The 1936 radio serviceman shown here is netting an extra five dollars is netting an extra five dollars for the service call, simply because he uttered the words, “any other electrical appliances in your home need repairing?”

The accompanying article, in the October 1936 issue of Radio News points out that no serviceman would sneer at an extra $5, but these words often reminded customers of other repair needs that had slipped their mind.

One serviceman noted that during a recent call, he was delivering a midget radio decorated with Mother Goose characters for the customer’s nursery. After installing the set, he replaced a belt on a vacuum cleaner, repaired a few frayed electrical cords and damaged outlets, and replaced an old iron with a new automatic model. “Most people prefer to have radiomen repair their vacuum cleaners and other appliances since dealers too often send out high-pressur salesmen to attempt to sell new apparatus when only the simplest repair is required.”

1946 80 Meter Transmitter from Popular Science

Seventy years ago, the October 1946 issue of Popular Science showed the beginning ham how to put together this compact transmitter for 80 meters (on the left in this photo).

The set employed a single 7N7 dual triode, and was said to be capable of real performance. But the article warned to bear in mind that “the 80-meter band is crowded with high-power outfits, so you’ll have the best chance of getting through during the relatively quiet hours.”

The set was mounted on a 5×7 wooden base, and required a 250-300 volt power supply, as well as filament voltage. The antenna tuning unit was mounted on a separate chassis, with twisted lamp cord connecting the transmitter and tuner.

NBC Shortwave Listening Station, Bellmore, Long Island, 1941

Shown here in the October 25, 1941, issue of Radio Guide is the Shortwave Listening Station which the NBC network had recently installed at Bellmore, Long Island. The station was in operation 24 hours a day, and the staff of 24 foreign language experts and radio engineers kept tab on the war of words coming from Europe.

The issue also reported on a publicity stunt recently conducted by Berlin Radio. For a number of days, the station had announced that Lord Haw Haw had been banned from the air. Then, an announcement followed that Lord Haw Haw would be allowed to come on the air and give his side of the story.

Many American editors fell for it, and the broadcast received plenty of advance publicity. However, Lord Haw Haw hadn’t been banned from the German airwaves. It was a publicity stunt in which he announced merely that the American networks refused to carry his propaganda.

1936 “Wrist Watch” Radio

You can probably barely see it, but this gentleman is listening to an ultra-compact radio, as described 80 years ago in the October 1936 issue of Popular Science.

This “wrist-watch” radio is crammed into a chassis measuring two and a half inches square. It’s a two-tube circuit, but uses a dual 6A8 tube, with one half serving as regenerative detector and the other half as audio amplifier to drive the headphones. The set is powered by batteries around the gentleman’s waist. If you look very carefully at the photo, you might see them.

The set called for a fifteen foot antenna, which he is presumably dragging along.

So even in 1936, if you wanted an ultra-discrete method to listen to the radio, you could put together one of these, and nobody would even notice that you had a radio with you.

Four Reasons Why You Need Two Radios: 1936

Eighty years ago, consumers buying a new radio had come to expect that they could trade in the old set. This presented a headache for the retailer, since any sale of the used set would probably cut into sales of new sets. The trade press often contained pointers on what to do with these old sets, such as donating them to charitable organizations, or selling them in bulk to other dealers, hopefully in another town, so that they would be another market’s problem.

The October 1936 issue of Radio Retailing included this graphic to help salesman convince buyers that they would be better off having two sets.
The page was designed to be shared with customers, and noted that “many questions asked by the consumer are difficult to answer because of his limited technical knowledge and inability to visualize.” Thus, the graphic was easier to understand, “and most people believe much of what they see in print.” Thus, graphics such as this one were printed to assist the salesman close a deal by “picturing the answer to a specific question which introduces selling resistance.”

This page notes that the old radio is worth more than the maximum trade-in value any dealer could allow, and suggests four uses for the old set. First, it could be moved to the playroom, allowing the parents to “duck the kid’s programs without breaking their hearts.”

Another viable option would be the bedroom. The magazine notes that it could be connected to an automatic time switch for a musical alarm.

In the kitchen, “any good serviceman can remove the chassis and build it in” for a truly modern kitchen.

The final use would be in the “whoopee room,” where we see a group playing ping pong and enjoying cool beverages, listening to the old set which has been “painted, in color, for that modernistic touch.”

1926 Homemade Battery Charger

One of the electronic components we take for granted today is the semiconductor diode for use as a rectifier. But even ninety years ago, if you wanted to build your own battery charger, you could do it at home, as shown by these plans from the October 1926 issue of Popular Mechanics.

To charge a six volt battery, this charger used a 12 volt doorbell transformer. The rectifier consisted of a glass jar containing a solution of borax, with electrodes made of lead and aluminum. The total cost of all of the parts was said to be $2.50.