Emergency radio
Encyclopedia
An emergency radio is, broadly speaking, a radio
receiver
designed to remain functional in cases of power outage or isolation from contact with civilization. Such radios are often designed to run on minimal or no power sources.
Emergency radios (all but the least expensive) are generally designed to cover more than just the standard AM
and FM broadcasting
bands; basic shortwave radio coverage (for situations where local radio is out or not available) is common, as well as weather radio in countries that provide that service.
Common to all emergency radios is the need to maintain power as long as possible in times of power failure. Commonly, such radios are designed to use minimal battery
power, and a common feature (especially on units sold in less-developed countries where electrical supplies may be unreliable or nonexistent) is a hand-cranked electrical generator
along with a rechargeable battery
to store the generated energy (the device is sometimes known as a clockwork radio
). A few, such as the Blackout Buddy from Eton Corporation
, are designed to recharge from wall current.
Radio
Radio is the transmission of signals through free space 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...
receiver
Receiver (radio)
A radio receiver converts signals from a radio antenna to a usable form. It uses electronic filters to separate a wanted radio frequency signal from all other signals, the electronic amplifier increases the level suitable for further processing, and finally recovers the desired information through...
designed to remain functional in cases of power outage or isolation from contact with civilization. Such radios are often designed to run on minimal or no power sources.
Emergency radios (all but the least expensive) are generally designed to cover more than just the standard AM
AM broadcasting
AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is carried out in the medium wave band world wide, and on long wave and short wave...
and FM broadcasting
FM broadcasting
FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...
bands; basic shortwave radio coverage (for situations where local radio is out or not available) is common, as well as weather radio in countries that provide that service.
Common to all emergency radios is the need to maintain power as long as possible in times of power failure. Commonly, such radios are designed to use minimal battery
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
power, and a common feature (especially on units sold in less-developed countries where electrical supplies may be unreliable or nonexistent) is a hand-cranked electrical generator
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
along with a rechargeable battery
Rechargeable battery
A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...
to store the generated energy (the device is sometimes known as a clockwork radio
Clockwork radio
A windup radio or clockwork radio is a radio that is powered by human muscle power rather than batteries or the electrical grid. In the most common arrangement, an internal electrical generator is run by a mainspring, which is wound by a hand crank on the case. Turning the crank winds the spring...
). A few, such as the Blackout Buddy from Eton Corporation
Eton Corporation
Etón Corporation is an American company established over 25 years ago based in Palo Alto, California, formerly known as Lextronics. It is famous for its line of shortwave and emergency hand-crank radios. It also sells Grundig-branded radios in North America and Europe...
, are designed to recharge from wall current.