February 28, 2006

DELAYING THE BROADCAST (Jun, 1939)

The guy in this article absolutely fits my definition of a hacker. There was a problem where two radio stations were broadcasting the same syndicated content on the same frequency. Listeners near either station had no problem. However there were locations where both signals could be recieved. This would be fine, except for the fact that the cable running to one of the stations was longer than the other, so the signal was delayed by 1/23000 of a second. Enough to cause destructive interference. So the engineers solution was to create an acoustic delay line out of 23 feet of lead pipe stuffed with cloth and gauze with a speaker on one side and a microphone on the other. The slower speed of sound delayed the signal long enough for the two stations to be in sync.

DELAYING THE BROADCAST

A FEW weeks ago the popular radio show, Information Please, used the following catch question:

“Who hears the speaker first, the people at the back of the auditorium, or the people 3,000 miles across the country who are listening to the broadcast of the speech?”

The catch was that radio waves travel with the speed of light, 186,000 miles per second, and sound waves only 1,080 feet per second. Therefore, the answer went, the listeners three thousand miles away would hear it first.

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February 20, 2006

“Radio Nurse” Watches Child (Jul, 1938)

Did you think that the baby monitor was a recent invention?

“Radio Nurse” Watches Child

A “RADIO NURSE” now brings the nursery into the living room, kitchen, or any other room desired. When a child is sleeping or playing in a room when no older persons are present, every sound within that room can be transmitted to any spot in the house. The outfit consists of a pickup unit, placed near the child to be “watched,” and a loudspeaker, which can be placed in any convenient location.

February 14, 2006

Sun Hat Has Built-in Radio (Jun, 1949)

I love the two little vacuum tubes sticking out on top.

Sun Hat Has Built-in Radio

No, that’s not Buck Rogers. It’s just Victor T. Hoeflich and his Radio Hat®. The hat works, too—it keeps the sun off your head while you listen to radio programs. The Radio Hat contains a real radio receiver-two miniature tubes, the volume control,
and the antenna (which looks like an oil-can handle) stick out on top. The rest of the circuit is inside the hat’s lining.
The hat weighs only 12 oz. The 7-oz. power supply—a flashlight cell and a B battery—is carried in the pocket. Mr. Hoeflich’s company, American Merri-Lei Corp., Brooklyn, N. Y., makes the talking benny.

January 30, 2006

“Tiny” Walking Radio (Feb, 1937)

Filed under: Radio, Useful — @ 10:51 am
Source: Modern Mechanix ( More articles from this issue )
Issue: Feb, 1937
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Devise Tiny Walking Radio

A NOVEL radio transmitter is used by representatives of the Columbia Broadcasting System to conduct roving interviews. The device consists of an antenna and radio frequency oscillator mounted in a cane, a microphone on a wrist strap, batteries in a money belt, and an audio amplifier and modulator in a binocular case. Working range is one mile.

January 24, 2006

Pictures by Radio (Jun, 1939)

Filed under: Radio — @ 12:36 pm
Source: Mechanix Illustrated ( More articles from this issue )
Issue: Jun, 1939
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The printout actually looks really good, though at 3 feet per hour it isn’t the most useful thing in the world.

Pictures by Radio

RADIO facsimile, the process by which pictures and printed matter are transmitted over the air for identical reproduction at the receiving end, is rapidly advancing as a new and valuable service of radio broadcasting. An experimental facsimile network has been established as part of the Mutual Broadcasting System, and already three important stations, WGN, WOR and WLW, are transmitting on regular schedule. Factory-made receivers of medium price are being produced by a large radio set manufacturer and are now advertised and sold by department stores.

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December 7, 2005

Transistor Pocket Radio (Jan, 1955)

Transistor Pocket Radio
THERE ARE NO vacuum tubes employed in this transistor pocket radio recently introduced by Regency of Indianapolis, Ind. It is claimed to be several years ahead of the time set by many stereatronics experts for the development of such a unit for consumer use.
This model, TR-l, is priced at $49.95 and comes in four colors: Black, bone white, cloud white and mandarin red. It measures 3 by 5 by 1.25 inches and weighs less than 12 ounces. Its size is, of course, made possible by the use of tiny high-performance transistors. A miniature 22.5-volt battery supplies the power for the radio.
Photos A and B illustrate the diminutive size of this ultra compact pocket set. The transistor used is known as a grown junction n-p-n type and only four are used in the entire set. This circuit, Fig. 1, uses one transistor as a combination mixer-oscillator, two as intermediate-frequency amplifiers and one as an audio amplifier. A germanium diode is used as a detector.
One of the features of this truly pocket radio is the advantage of long battery life as the power consumption is only a fraction of that required for a comparable vacuum tube unit. This results in a considerable saving in weight and battery-replacement cost. Service problems of tube replacement are eliminated; transistors operate in a different manner from vacuum tubes. The hot filament or cathode in a vacuum tube is continually being consumed as it is operated. No similar life-shortening action takes place in transistors.

November 21, 2005

Walkie-Talkie Carhops Speed Service (Dec, 1955)

The young lady in the photo (left) uses the lightweight walkie-talkie to call orders into the kitchen at Schilling’s Drive-in Restaurant near Covington, Ky. The woman in the car thus gets her food faster. It’s part of an electronic setup developed by Frank Lindley of Cincinnati. An operator at a reciever takes down orders fromt he walkie-talkie carhops. Then, when the food and check are ready, the carhops are alerted by different-colored lights on signal boxes located so that they can be seen from anywhere in the parking lot.

November 18, 2005

Kerosene Radio (Jun, 1956)

“Hold on ma, let me go light the radio!”

Made in Moscow for use in rural areas, this all-wave radio is reportedly powered by the kerosene lamp hanging above it. A group of thermocouples is heated internally to 570 degrees by the flame. Fins cool the outside to about 90 degrees. The temperature differential generates enough current to operate the low-drain reciever. Regular listeners may want fur lined union suits, though: it works best in a room with open windows.

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