Radio is the transmission of signals by modulation of electromagnetic waves with

frequencies below those of visible light. Electromagnetic radiation

travels by means of oscillating electromagnetic fields that pass through the air and

the vacuum of space. Information is carried by systematically

changing (modulating) some property of the radiated waves, such as

amplitude, frequency, or phase. When radio waves pass an electrical conductor,

the oscillating fields induce an alternating current in the conductor. This can be

detected and transformed into sound or other signals that carry information.

There was some home recording of radio in the 1930s and early 1940s. Home

recording at that time could typically only be performed by home disk recorders,

which were only capable of storing five minutes of a radio program per side on a

seven-inch record. As a result of the short durations of these records and the

expense of the recorders, home recording was uncommon during this period.

The lack of suitable home recording equipment was somewhat relieved in 1943

with the introduction of home tape recorders using Scotch 100 tape. However, the

quality of recordings made from these devices was far below professional levels. In

fact, home recording of radio programs did not become common until around

1950, when affordable reel-to-reel tape recorders were introduced to the market

In the beginning of the Golden Age, American radio network programs were

presented almost exclusively live, since the national networks prohibited the airing

of recorded programs until the late 1940s. As a result, prime-time shows would be

performed twice for both coasts. However, some programs were recorded as they

were broadcast during this period, typically for syndicated programs or for

advertisers to have their own copy. When the networks became more open to

airing recorded programs in the 1950s and 1960s, recordings became more

common.

The RCA 44BX microphone had two live faces and two dead ones. Thus actors

could face each other and react. One could give the effect of leaving the room by

moving one's head toward the dead face of the microphone. The scripts were

paper clipped together and pages were dropped to the carpeted floor after use.

Sometimes when reassembling a script to use it for the next time zone, pages would

be out of order or missing entirely.

Work done by: Bruno NR 1

Joaquim NR 10

Rui NR 16