Analog Radio
Analog radio consists of
two main types: AM (amplitude modulation) and FM (frequency
modulation). Analog radio station frequently feeds only one transmitter and
referred to as an AM station or an FM station in the U.S. But it is quite
possible for a station to feed both transmitters in a similar area, or to feed
more than one transmitter covering different areas. In either case, AM or FM
refers only to a particular transmitter and not to the entire station. The
latter arrangement is becoming widespread throughout the U.S.
Satellite Radio
One of the newest forms
of broadcasting, satellite radio is a commercial, subscription-based service
that uses a network of satellites to transmit signals over wide areas. Unlike
traditional AM and FM broadcasts, satellite radio is digitally encoded, requiring
a special receiver. Even with the receiver, you cannot tune in unless you have
a paid subscription; a computer chip in the receiver locks out any channels not
paid for. Advantages of satellite radio include good sound quality, nationwide
coverage and access to material that sidesteps the Federal Communications
Commission's ban on profanity.
Walkie-Talkie
A walkie-talkie is a
portable, handheld device that sends and receives radio signals, usually within
a range of about a mile. Walkie-talkies are used by two or more people to
communicate in situations where cell phone service is poor or unavailable, such
as in remote locations or in buildings. Because walkie-talkies have low power
and short range, you don't need a special license to operate them; they
interfere little with other radio signals.
Amateur radio (ham
radio)
Amateur radio, also
known as ham radio, is a hobby enjoyed by several hundred thousand people in
the United States and by over a million people worldwide. Amateur radio
operators call themselves "radio hams" or simply "hams."
To become a radio ham, you must pass an examination. Wireless amateur
communication is done on numerous bands (relatively narrow frequency segments)
extending from 1.8 MHz (a wavelength of about 160 meters)
upwards through several hundred gigahertz (wavelengths in the millimeter
range). There are several license classes. The more privileges a
class of license conveys, the more difficult is the examination that one must
pass to obtain it.
Happy Learning!
Anamika Gupta
IAAN