radio

1. Radio Broadcasting
Radio Broadcasting
■ Radio has its roots in the
Radio has its roots in the
Telegraph.
Telegraph.
■ This device was the first
This device was the first
widely-used form of long-
widely-used form of long-
distance communication.
distance communication.
■ In 1836, Samuel Morse
In 1836, Samuel Morse
invented a language of
invented a language of
dots and dashes that is
dots and dashes that is
still used today.
still used today.

2. Radio Broadcasting
Radio Broadcasting
■ In 1876, Alexander
In 1876, Alexander
Graham Bell transmitted
Graham Bell transmitted
the human voice over
the human voice over
wires for the first time.
wires for the first time.
■ Soon, his invention
Soon, his invention
moved from the lab to
moved from the lab to
the home and life hasn't
the home and life hasn't
been the same since.
been the same since.

3. Radio Broadcasting
Radio Broadcasting
■ Most of these telephones
Most of these telephones
were wired on party
were wired on party
lines, which means that
lines, which means that
many of your neighbors
many of your neighbors
could listen to your calls.
could listen to your calls.
■ All the phones on the
All the phones on the
party line rang at one
party line rang at one
time, and each home
time, and each home
had its own ring pattern.
had its own ring pattern.

4. Radio Broadcasting
Radio Broadcasting
■ In 1887, Heinrich Hertz
In 1887, Heinrich Hertz
demonstrated that
demonstrated that
electromagnetic waves
electromagnetic waves
could be transmitted
could be transmitted
through the air.
through the air.
■ As a result, the term
As a result, the term
"Hertz" is now used to
"Hertz" is now used to
specify cycles per second
specify cycles per second
for the frequency of both
for the frequency of both
sound and radio waves.
sound and radio waves.

5. Radio Broadcasting
Radio Broadcasting
■ In 1883, a dentist named
In 1883, a dentist named
Mahlon Loomis received
Mahlon Loomis received
the patent for wireless
the patent for wireless
telegraphy, but
telegraphy, but
■ Guglielmo Marconi is
Guglielmo Marconi is
commonly credited as
commonly credited as
inventing radio in 1895
inventing radio in 1895
even though there is
even though there is
credible evidence that
credible evidence that
other inventors were first.
other inventors were first.

6. Radio Broadcasting
Radio Broadcasting
■ Nikola
Nikola Tesla demonstrated
wireless transmissions
during a lecture on the
potential of high frequency
transmitting in 1891.
■ In 1893, after continued
research, Tesla presented
a paper on the basics of
radio (wireless telegraph).

7. Radio Broadcasting
Radio Broadcasting
■ Once Marconi patented
Once Marconi patented
his invention in England,
his invention in England,
his next step was to sell
his next step was to sell
it to the marine industry.
it to the marine industry.
■ Soon, the majority of
Soon, the majority of
oceangoing ships were
oceangoing ships were
all equipped with his
all equipped with his
equipment - which made
equipment - which made
Marconi a very rich man.
Marconi a very rich man.

8. Radio Broadcasting
Radio Broadcasting
■ Ship radio operators who
Ship radio operators who
had never heard anything
had never heard anything
but Morse code received
but Morse code received
the first radio broadcast
the first radio broadcast
from Boston in 1906.
from Boston in 1906.
■ It must have seemed like
It must have seemed like
the Twilight Zone at sea
the Twilight Zone at sea
when the ships heard
when the ships heard
Christmas carols coming
Christmas carols coming
from their radios!
from their radios!

9. Radio Broadcasting
Radio Broadcasting
■ In 1912, a tragedy
In 1912, a tragedy
happened that shook the
happened that shook the
World. The "unsinkable"
World. The "unsinkable"
luxury liner, the Titanic,
luxury liner, the Titanic,
hit an iceberg and sank.
hit an iceberg and sank.
■ The tragedy could have
The tragedy could have
been worse. Thanks to
been worse. Thanks to
the new invention of
the new invention of
radio, about 800 people
radio, about 800 people
were saved.
were saved.

10. Radio Broadcasting
Radio Broadcasting
■ In the early days of radio
In the early days of radio
there was no way to
there was no way to
record sound - everything
record sound - everything
was performed "live."
was performed "live."
■ Although the first sound
Although the first sound
recording device can be
recording device can be
traced back to 1855, it
traced back to 1855, it
was some time before the
was some time before the
concept was applied to
concept was applied to
radio.
radio.

11. Radio Broadcasting
Radio Broadcasting
■ In 1898, Danish inventor
In 1898, Danish inventor
Valdemar Poulsen created
Valdemar Poulsen created
the Telegraphone, the
the Telegraphone, the
first practical magnetic
first practical magnetic
sound recorder using a
sound recorder using a
piano wire as the
piano wire as the
recording medium.
recording medium.
■ Soon, wire recorders
Soon, wire recorders
begin to appear on the
begin to appear on the
American market.
American market.

12. Radio Broadcasting
Radio Broadcasting
■ 8XK (now KDKA) in
8XK (now KDKA) in
Pittsburgh, Pennsylvania
Pittsburgh, Pennsylvania
is widely credited as the
is widely credited as the
first radio station in the
first radio station in the
US, but the truth is that
US, but the truth is that
■ other stations preceded
other stations preceded
8XK, but Frank Conrad
8XK, but Frank Conrad
did start the first daily
did start the first daily
program on that station.
program on that station.

13. Radio Broadcasting
Radio Broadcasting
■ Conrad initially played
Conrad initially played
music by holding a mic up
music by holding a mic up
to a phonograph.
to a phonograph.
■ In no time, people were
In no time, people were
tuning in, and Conrad
tuning in, and Conrad
became a mini-celebrity.
became a mini-celebrity.
■ Westinghouse, who
Westinghouse, who
owned the station, took
owned the station, took
notice and expanded
notice and expanded
Conrad's operations.
Conrad's operations.

14. Radio Broadcasting
Radio Broadcasting
■ Once radio broadcasting
Once radio broadcasting
was launched, people
was launched, people
began to realize just how
began to realize just how
significant this new
significant this new
medium could be.
medium could be.
■ For example, KDKA,
For example, KDKA,
broadcast the 1920
broadcast the 1920
Harding-Cox presidential
Harding-Cox presidential
election returns well in
election returns well in
advance of the papers.
advance of the papers.

15. Radio Broadcasting
Radio Broadcasting
■ The popularity of the
The popularity of the
new medium enticed
new medium enticed
people to build their own
people to build their own
personal radio stations.
personal radio stations.
■ Soon there were too
Soon there were too
many stations for the
many stations for the
number of frequencies
number of frequencies
available on the radio
available on the radio
dial.
dial.

16. Radio Broadcasting
Radio Broadcasting
■ In 1922, another element
In 1922, another element
entered the picture —
entered the picture —
broadcast advertising.
broadcast advertising.
■ What was originally
What was originally
referred to as a “toll
referred to as a “toll
broadcast” is now known
broadcast” is now known
as a commercial.
as a commercial.
■ Along with the advent of
Along with the advent of
ads came sponsors and
ads came sponsors and
the need for regulation.
the need for regulation.

17. Radio Broadcasting
Radio Broadcasting
■ The Congress passed the
The Congress passed the
Radio Act of 1927, which
Radio Act of 1927, which
created the Federal
created the Federal
Radio Commission - FRC.
Radio Commission - FRC.
■ Its purpose was to
Its purpose was to
oversee the licensing of
oversee the licensing of
transmitters, assigning
transmitters, assigning
radio frequencies, call
radio frequencies, call
letters, and power limits.
letters, and power limits.

18. Radio Broadcasting
Radio Broadcasting
■ Call letters for stations
Call letters for stations
east of the Mississippi
east of the Mississippi
start with a "W", and
start with a "W", and
stations west of the
stations west of the
Mississippi start with "K."
Mississippi start with "K."
■ A few stations were
A few stations were
licensed before this rule
licensed before this rule
was put in to effect, so
was put in to effect, so
there are couple of
there are couple of
exceptions.
exceptions.

19. Radio Broadcasting
Radio Broadcasting
■ In 1934, the FRC was
In 1934, the FRC was
reorganized into Federal
reorganized into Federal
Communications
Communications
Commission or the FCC.
Commission or the FCC.
■ The FCC's regulatory
The FCC's regulatory
powers were expanded
powers were expanded
to include telephone and
to include telephone and
telegraph - and some
telegraph - and some
years later, television.
years later, television.

20. Radio Broadcasting
Radio Broadcasting
■ The FCC reserved some
The FCC reserved some
nonprofit frequencies for
nonprofit frequencies for
educational and religious
educational and religious
groups.
groups.
■ Due to the big-business
Due to the big-business
bias of the government,
bias of the government,
these frequencies were
these frequencies were
the least desirable and
the least desirable and
were limited in power.
were limited in power.

21. Radio Broadcasting
Radio Broadcasting
■ AM stands for amplitude
AM stands for amplitude
modulation, and ranges
modulation, and ranges
from 535 to 1705kHz.
from 535 to 1705kHz.
■ Kilohertz are thousands
Kilohertz are thousands
of cycles per-second of
of cycles per-second of
electromagnetic energy.
electromagnetic energy.
■ These are the numbers
These are the numbers
you see on your AM
you see on your AM
radio dial.
radio dial.

22. Radio Broadcasting
Radio Broadcasting
■ The tan area at the left are AM radio waves and
The tan area at the left are AM radio waves and
are at a lower frequency than FM radio or TV
are at a lower frequency than FM radio or TV
■ Stations can be placed every 10kHz along the AM
Stations can be placed every 10kHz along the AM
band so there are 117 channels available.
band so there are 117 channels available.

23. Radio Broadcasting
Radio Broadcasting
■ The signals of most AM
The signals of most AM
stations are limited in
stations are limited in
their range, so the same
their range, so the same
frequencies can be used
frequencies can be used
many times as long as
many times as long as
they are separated.
they are separated.
■ This is how we can have
This is how we can have
nearly 5,000 AM radio
nearly 5,000 AM radio
stations in the US on 117
stations in the US on 117
different frequencies.
different frequencies.

24. Radio Broadcasting
Radio Broadcasting
■ Modulation refers to how
Modulation refers to how
sound is encoded on a
sound is encoded on a
radio wave (called a
radio wave (called a
carrier wave) so that the
carrier wave) so that the
sound can be detected
sound can be detected
by a radio receiver.
by a radio receiver.
■ The top drawing is not
The top drawing is not
modulated by any sound
modulated by any sound
so there would be
so there would be
silence on your radio.
silence on your radio.

25. Radio Broadcasting
Radio Broadcasting
■ FM or frequency
FM or frequency
modulated radio and TV
modulated radio and TV
waves act differently
waves act differently
than AM radio waves.
than AM radio waves.
■ The FM radio band goes
The FM radio band goes
from 88 to 108 MHz
from 88 to 108 MHz
(megahertz, or millions
(megahertz, or millions
of cycles per second).
of cycles per second).

26. Radio Broadcasting
Radio Broadcasting
■ FM stations must be
FM stations must be
200kHz apart which
200kHz apart which
means that there's room
means that there's room
for 200 FM stations on
for 200 FM stations on
the FM band.
the FM band.
■ FM stations don't have
FM stations don't have
nice round numbers like
nice round numbers like
820 or 1240. Instead, an
820 or 1240. Instead, an
FM station may be at
FM station may be at
88.7 on the dial.
88.7 on the dial.

27. Radio Broadcasting
Radio Broadcasting
■ FM and TV signals travel
FM and TV signals travel
in a straight line and
in a straight line and
don't bend around the
don't bend around the
earth as AM waves do.
earth as AM waves do.
■ The farther away from
The farther away from
the FM or TV station you
the FM or TV station you
are, the higher you have
are, the higher you have
to have an antenna to
to have an antenna to
receive the signal.
receive the signal.

28. Radio Broadcasting
Radio Broadcasting
■ Frequency relates to the
Frequency relates to the
pitch of a sound - how
pitch of a sound - how
high or low it is. A 20 Hz
high or low it is. A 20 Hz
frequency sound is
frequency sound is
extremely low-pitched -
extremely low-pitched -
almost a rumble.
almost a rumble.
■ A 20,000 Hz sound is the
A 20,000 Hz sound is the
highest pitched sound
highest pitched sound
that can be imagined.
that can be imagined.

29. Radio Broadcasting
Radio Broadcasting
■ A person with very good
A person with very good
hearing will be able to
hearing will be able to
hear sounds from
hear sounds from
20-20,000 Hz.
20-20,000 Hz.
■ The common range used
The common range used
for FM radio and TV is
for FM radio and TV is
from 50 to 15,000 Hz.
from 50 to 15,000 Hz.
and AM radio is below
and AM radio is below
this range.
this range.

30. Radio Broadcasting
Radio Broadcasting
■ The average US resident
The average US resident
listens to 22 hours of
listens to 22 hours of
Radio per week
Radio per week
■ In the US, Radios out-
In the US, Radios out-
number people 3 to 1
number people 3 to 1
■ In most countries, Radio
In most countries, Radio
continues to be the
continues to be the
primary source of news
primary source of news
and information
and information