Museum of Innovation and Science

Exploring an AM/FM Radio

Betty Bower, technician on WGY-radio engineering staff, tries her hand at creating radio sound effects, December 1942

Take a Bow

Explore the changing methods people used to listen to radio in its early days, from wireless telegraphy to transistor radios.

Listening to Radio

Tabletop television, 1948. It originally cost $200 and had a 10-inch diagonal screen

In Days Gone By

Program Description

The invention of radio allowed for a transformation in the way that people seek entertainment for themselves. Music, plays, and dramas sent over radio waves allowed individuals and families alike to hear stories that they may not have encountered otherwise, especially when up until that point all entertainment was done in a collective setting, such as a tale around a fire, or through travelling actors.

In the following activities, students will begin to explore how the invention and evolution of televisions and radios allowed for a massive cultural shift, one that continues to happen with technology we continue to use today.


·        Understand the difference between satellite radio and conventional radio stations, and how the use of a tuner is essential to the latter

·        Describe the changes that both the radio and television have gone through, from their invention to now, and identify those changes through observations of advertisements

·        Distinguish differences in writing for radio vs. writing for television by creating their own radio play

·        1-PS4-4. Use tools and materials to design and build a device that uses light or sound to solve the problem of

o  Clarification Statement: Examples of devices could include a light source to send signals, paper cup and string “telephones,” and a pattern of drum beats.

o  Assessment Boundary: Assessment does not include technological details for how
communication devices work

·        MS-PS4-3. Integrate qualitative scientific and technical information to support the claim that digitized signals are a more reliable way to encode and transmit information than analog signals.

o  Clarification Statement: Emphasis is on a basic understanding that waves can be used for communication purposes. Examples could include using fiber optic cable to
transmit light pulses, radio wave pulses in Wi-Fi devices, and conversion of stored binary patterns to make sound or text on a computer screen.

o  Assessment Boundary: Assessment does not include binary counting. Assessment does not include the specific mechanism of any given device

Radio: Instant Communication and Information

Engineering and Technology

Science

U.S. History

Social Studies

Early users of radio could only receive and transmit the electromagnetic pulses used in Morse Code. Although Marconi developed the first wireless system in 1895, the first voice broadcast of radio did not occur until 1906.

By the early 1920s, most radios detected sound using tiny galena mineral crystals. Headphones, modified from a telephone receiver, could be used to listen to the sound.

In 1922 GE created a series of images of a young girl demonstrating the different methods of listening to radio. Here she listens to a Radiola V radio receiver using headphones.

Engineers developed loudspeaker horns so that more than person could listen to a radio receiver at a time. The horns used a variation of an early headphone speaker as the sound source, and used the horn to amplify the sound.

The Radiola III was the first mass produced radio, with 293,000 receivers manufactured. There were fewer than 10,000 manufactured of its predecessor, the Radiola II. It cost $35 to purchase at a time when a radio engineer earned a starting salary of $27 per week. This radio was owned by GE radio inventor Ernst Alexanderson (1878-1975).

The young girl listens to the Radiola V using a loudspeaker horn. The horn had a limited sound quality and no ability to increase the volume, so engineers sought a better way to produce sound from a radio.

This was a prototype of the loudspeaker developed by Clarence Hewlett, Edward Kellogg and Chester Rice at the GE Research Laboratory for use in radios and theaters.

The Radiola 28 radio receiver (left), cost $260 but did not include a speaker. In advertising it was often paired with one of the electrodynamic loudspeakers, the Radiola 104. The original cost of the Radiola 104 was $260, at a time when an entry level radio engineer earned $27 per week.

A young girl listens to an RCA Radiola IV radio through a built-in speaker

The Radiola 26 was one of the first truly portable radios, despite weighing 25 pounds. In addition to being one of the first radios with a built-in speaker, the antenna is part of the door, and the radio also contains a battery compartment in the rear. The radio sold for $225.

The development of the transistor radio, replacing vacuum tubes, allowed engineers and designers to shrink the size of the radio. Because transistor radios were pocket-sized and portable, headphones came back into popularity, including a new variation, the earbud.

Resource Kits

Object Library

Museums

Radio: Instant Communication and Information

Listening to Radio

Wireless telegraph, circa 1915