Radio Waves

Before beginning our research
on radio waves, to us, radio waves were just
waves going through the atmosphere, carrying
sound from one place to another. Those were our
ignorant days! We did not realize the complicated
terms and theories involved. In the following
report you will see how we advanced in our
knowledge of radio waves, and we hope it will do
the same for you. Radio waves are a combination
of two kinds of electric vibrations. Audio
frequency waves, which represent voice and other
sounds and radio frequency waves, which carry
audio waves after being combined with them. Two
examples of broadcast waves are AM waves and
FM waves. AM which stands for amplitude
modulation, is a broadcasting method in which the
carrier waves (carry the sounds of a program) are
changed to match changes in the audio frequency
waves. These are electric waves that represent the
sounds of a radio broadcast. FM stands for
frequency modulation and these waves, that go
skyward, are not reflected. Instead, they pass
through the atmosphere and go into space. AM
signals, however, reflect off the atmosphere and
travel back down to earth, causing broadcasts to
be received at a much greater distance than FM
signals. Since FM travels all the way to space and
it does not bounce off the ground it does not
create as much static as AM does. Radio waves,
which travel at the speed of light, cannot be seen,
heard, or felt in any way. When you listen to the
radio, contrary to what some think, you are
hearing the receivers pick up the waves and turn
them into sound. Three more types of radio waves
are; ground waves, ionospheric waves and
tropospheric waves. Ground waves travel from
the antenna along the surface of the earth.
Ionospheric waves, otherwise known as sky
waves, are made up of radio waves that come
from a transmitting antenna and go into the sky.
The ionosphere is the region of the rare field and
ionized atmosphere around the earth, from 50 to
200 miles. Last but not least are the tropospheric
waves. These waves are parts of the original wave
which is reflected into the troposphere, an area of
clouds and storms from 3 to 7 miles high. Radios
change sound into electrical patterns with
transmitters. In a radio transmitter, the circuit that
generates the high frequency AC current that
produces radio waves from an antenna, is called
an oscillator. Electrical patterns are then changed
into broadcast waves of electromagnetic energy.
The Kenelly-Heairside layer, found in a
transmission of a radio is now well known. This
keeps the energy spent by a shortwave transmitter
from escaping into space. This is why we are able
to receive shortwave from such a great distance.
Sound is changed into radio waves at a radio
broadcast station. The microphone, which is used,
changes the sound into an electrical current. The
transistors in an amplifier increase the strength of
the current. Then, the current goes into the
transmitter which is connected to an antenna. The
antenna sends out the radio waves. Although
broadcast waves are almost constantly
surrounding us, they can only be sensed by a
similar antenna. When you are turning the dial on
your radio to get a new station, you are actually
picking up a new broadcast frequency. The
frequency of a wave is the number of cycles that
happen in one second. Hertz is a unit used to
measure frequency. 1 Hertz is equal to 1 vibration
per second. There is a way to figure out the speed
at which a radio wave travels. It is by multiplying
the frequency of a wave by its wave length. The
wave length is the distance between peaks.
Diodes can detect radio waves. They were used in
radio broadcasting, but transistors have taken their
place. Radio waves are used in much more than
just radios. They are also used in cordless
telephones, television channels, and many
appliances in the average home. In conclusion,
radio waves have become part of everyday life,
and almost a necessity. Radio waves are just
another example of our advancing technology on
earth. As you have seen, radio waves are very
complex. We hope our report has enabled you to
further understand radio waves, it sure has for us!

Category: Science