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War Emergency Radio Service
The War Emergency Radio Service (WERS) was a United States civil defense, civil defense service in the United States from 1942 to 1945. It was replaced by the current Radio Amateur Civil Emergency Service, Radio Amateur Civil Emergency Service (RACES) system. History When the United States entered the World War II, Second World War, the United States Congress had suspended all amateur radio activity throughout the country. WERS was established by the Federal Communications Commission in June 1942 at the insistence of the American Radio Relay League. WERS was to provide Radio communications, communications in connection with airstrike, air raid protection, and communications during natural disasters. WERS licenses were given to communities, not to individuals; one of the requirements for individuals to participate in the WERS was to hold an Amateur radio license. At the end of 1944, about five thousand radio transmitters operated under 250 licenses. WERS remained in operat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Civil Defense
United States civil defense refers to the use of civil defense in the history of the United States, which is the organized non-military effort to prepare Americans for military attack and similarly disastrous events. Late in the 20th century, the term and practice of civil defense fell into disuse. Emergency management and homeland security replaced them. History Pre–World War There is little known history of civil defense in the United States before the twentieth century. Since ancient times, cities typically built walls and moats to protect from invasion and commissioned patrols and watches to keep an eye out for danger, but such activities have not traditionally been encompassed by the term "civil defense." The U.S. has a particular lack of early civil defense efforts because it was seldom threatened with a significant attack. Nonetheless, there are some early examples of what would today be considered civil defense. For example, as early as 1692, the village of Bedfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio License
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications. The term "amateur" is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;" (either direct monetary or other similar reward) and to differentiate it from commercial broadcasting, public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and ''amateur-satellite service'') is established by the International Telecommunication Union (ITU) through the Radio Regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station licenses with a unique identifying call sign, which mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Station
An amateur radio station is a radio station designed to provide radiocommunications in the amateur radio service for an amateur radio operator. Radio amateurs build and operate several types of amateur radio stations, including fixed ground stations, mobile stations, space stations, and temporary field stations. A slang term often used for an amateur station's location is the shack, named after the small enclosures added to the upperworks of naval ships to hold early radio equipment and batteries. ;See also: Types of stations Fixed stations An amateur radio station established in a permanent structure with equipment that is not intended for portable operation is referred to as a ''fixed station''. This is the most common form of amateur radio station, and can be found in homes, schools, and some public buildings. A typical fixed station is equipped with a transceiver and one or more antennas. For voice communications, the station will be equipped with a microphone; fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Operator
An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way personal communications with other amateur operators on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio license by a governmental regulatory authority after passing an examination on applicable regulations, electronics, radio theory, and radio operation. As a component of their license, amateur radio operators are assigned a call sign that they use to identify themselves during communication. About three million amateur radio operators are currently active worldwide. Amateur radio operators are also known as radio amateurs or hams. The term "ham" as a nickname for amateur radio operators originated in a pejorative usage (like "ham actor") by operators in commercial and professional radio communities, and dates to wired telegraphy. The word was subsequently adopted by amateur radio operators. Demographics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Emergency Communications
In times of crisis and natural disasters, amateur radio is often used as a means of emergency communication when wireline, cell phones and other conventional means of communications fail. Unlike commercial systems, amateur radio is usually independent of terrestrial facilities that can fail. It is dispersed throughout a community without "choke points" such as cellular telephone sites that can be overloaded. Amateur radio operators are experienced in improvising antennas and power sources and most equipment today can be powered by an automobile battery. Annual " Field Days" are held in many countries to practice these emergency improvisational skills. Amateur radio operators can use hundreds of frequencies and can quickly establish networks tying disparate agencies together to enhance interoperability. Recent examples include the September 11 attacks on the World Trade Center in Manhattan in 2001, the 2003 North America blackout and Hurricane Katrina in September 2005 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Emergency Service
In the United States and Canada, the Amateur Radio Emergency Service (ARES) is a corps of trained amateur radio operator volunteers organized to assist in public service and emergency communications. It is organized and sponsored by the American Radio Relay League and the Radio Amateurs of Canada. Communication failures have been a defining part of natural disasters and even some human-generated events such as the September 11 attacks that occurred in New York City in 2001. A lack of communication between firefighters at the World Trade Center contributed directly to the deaths of 300 of those firefighters. Amateur radio provides a means of communication "when all else fails". Historical operations Amateur radio operators belonging to ARES (and its predecessor, the Amateur Radio Emergency Corps) have responded to local and regional disasters since the 1930s, including the attacks of September 11, 2001, and the category 5 storms Hurricane Katrina and Hurricane Mich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Of Civilian Defense
Office of Civilian Defense was a United States federal emergency war agency set up May 20, 1941, by to co-ordinate state and federal measures for protection of civilians in case of war emergency. Its two branches supervised protective functions such as blackouts and special fire protection and "war service" functions such as child care, health, housing, and transportation. It also created the Civil Air Patrol. The agency was terminated by Executive Order 9562 of June 4, 1945. The Office of Civil Defense with similar duties was established later. Fiorello La Guardia was the first head of the office, succeeded in 1942 by James M. Landis, followed in 1944 by General William N. Haskell. While the agency only had a paid staff of 75, it supervised and coordinated the efforts of civilian volunteers estimated to have topped 11 million. Volunteer tasks included firefighting and air-raid preparedness. Children, under adult supervision, could volunteer in the Junior Citizens Service Cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Oscillator
A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is a quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators. However, other piezoelectricity materials including polycrystalline ceramics are used in similar circuits. A crystal oscillator relies on the slight change in shape of a quartz crystal under an electric field, a property known as inverse piezoelectricity. A voltage applied to the electrodes on the crystal causes it to change shape; when the voltage is removed, the crystal generates a small voltage as it elastically returns to its original shape. The quartz oscillates at a stable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airband
Airband or aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as ''VHF'', or phonetically as ''"Victor"''. Different sections of the band are used for radionavigational aids and air traffic control. In most countries a license to operate airband equipment is required and the operator is tested on competency in procedures, language and the use of the phonetic alphabet. Spectrum usage The VHF airband uses the frequencies between 108 and 137 MHz. The lowest 10 MHz of the band, from 108 to 117.95 MHz, is split into 200 narrow-band channels of 50 kHz. These are reserved for navigational aids such as VOR beacons, and precision approach systems such as ILS localizers. , most countries divide the upper 19 MHz into 760 channels for amplitude modulation voice transmissions, on frequencies from 118 to 136.975 MHz, in steps of 25 kHz. In Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Disaster
A natural disaster is "the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community". A natural disaster can cause loss of life or damage property, and typically leaves some economic damage in its wake. The severity of the damage depends on the affected population's resilience and on the infrastructure available. Examples of natural hazards include: avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, hurricane ( tropical cyclone), ice storm, landslide, lightning, riverine flooding, strong wind, tornado, typhoon, tsunami, volcanic activity, wildfire, winter weather. In modern times, the divide between natural, man-made and man-accelerated disasters is quite difficult to draw. Human choices and activities like architecture, fire, resource management or even climate change potentially play a role in causing "natural disasters". In fact, the term "natural disaster" has been calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five major unincorporated territories, nine United States Minor Outlying Islands, Minor Outlying Islands, and 326 Indian reservations. The United States is also in Compact of Free Association, free association with three Oceania, Pacific Island Sovereign state, sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Palau, Republic of Palau. It is the world's List of countries and dependencies by area, third-largest country by both land and total area. It shares land borders Canada–United States border, with Canada to its north and Mexico–United States border, with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airstrike
An airstrike, air strike or air raid is an offensive operation carried out by aircraft. Air strikes are delivered from aircraft such as blimps, balloons, fighters, heavy bombers, ground attack aircraft, attack helicopters and drones. The official definition includes all sorts of targets, including enemy air targets, but in popular usage the term is usually narrowed to a tactical (small-scale) attack on a ground or naval objective as opposed to a larger, more general attack such as carpet bombing. Weapons used in an airstrike can range from direct-fire aircraft-mounted cannons and machine guns, rockets and air-to-surface missiles, to various types of aerial bombs, glide bombs, cruise missiles, ballistic missiles, and even directed-energy weapons such as laser weapons. In close air support, air strikes are usually controlled by trained observers on the ground for coordination with ground troops and intelligence in a manner derived from artillery tactics. History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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