Tropospheric scatter, also known as troposcatter, is a method of communicating with microwave radio signals over considerable distances – often up to 500 kilometres (310 mi) and further depending on frequency of operation, equipment type, terrain, and climate factors. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at UHF and SHF frequencies are randomly scattered as they pass through the upper layers of the troposphere. Radio signals are transmitted in a narrow beam aimed just above the horizon in the direction of the receiver station. As the signals pass through the troposphere, some of the energy is scattered back toward the Earth, allowing the receiver station to pick up the signal.
Missile guidance refers to a variety of methods of guiding a missile or a guided bomb to its intended target. The missile's target accuracy is a critical factor for its effectiveness. Guidance systems improve missile accuracy by improving its Probability of Guidance (Pg).
The Distant Early Warning Line, also known as the DEW Line or Early Warning Line, was a system of radar stations in the northern Arctic region of Canada, with additional stations along the north coast and Aleutian Islands of Alaska, in addition to the Faroe Islands, Greenland, and Iceland. It was set up to detect incoming bombers of the Soviet Union during the Cold War, and provide early warning of any sea-and-land invasion.
The Mid-Canada Line (MCL), also known as the McGill Fence, was a line of radar stations running east–west across the middle of Canada, used to provide early warning of a Soviet bomber attack on North America. It was built to supplement the Pinetree Line, which was located farther south. The majority of Mid-Canada Line stations were used only briefly from the late 1950s to the mid-1960s, as the attack threat changed from bombers to ICBMs. As the MCL was closed down, the early warning role passed almost entirely to the newer and more capable DEW Line farther north.
Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its target. This control may also command the missile to detonate, even if the missile has a fuze.
The Alaskan Air Command (AAC) is an inactive United States Air Force Major Command originally established in 1942 under the United States Army Air Forces. Its mission was to organize and administer the air defense system of Alaska, exercise direct control of all active measures, and coordinate all passive means of air defense. In addition, the command also supported Strategic Air Command elements operating through and around Alaska. It was redesignated Eleventh Air Force on 9 August 1990 and, concurrently, status changed from a major command of the United States Air Force to a subordinate organization of Pacific Air Forces.
The White Alice Communications System was a United States Air Force telecommunication network with 80 radio stations constructed in Alaska during the Cold War. It used tropospheric scatter for over-the-horizon links and microwave relay for shorter line-of-sight links. Sites were characterized by large parabolic, tropospheric scatter antennas as well as smaller microwave dishes for point-to-point links.
Royal Canadian Air Force Station Winisk was a military installation located in Winisk, Ontario.
Canadian Forces Station Lowther is a closed General Surveillance Radar station. It is located 12.7 miles (20.4 km) east-southeast of Mattice-Val Côté, Ontario. It was closed in 1987.
Highlands Air Force Station was a military installation in Middletown Township near the borough of Highlands, New Jersey. The station provided ground-controlled interception radar coverage as part of the Lashup Radar Network and the Semi-Automatic Ground Environment network, as well as providing radar coverage for the Highlands Army Air Defense Site. The site's 240 acres (97 ha) is now the Rocky Point section in Hartshorne Woods Park of the Monmouth County Parks System.
The North Atlantic Radio System (NARS) was a chain of 5 tropospheric scatter communication sites. It was an expansion of the former Distant Early Warning Line. NARS was built for the United States Air Force (USAF) by Western Electric (AT&T) and its sites were maintained under contract by ITT Federal Electric Corporation. All NARS stations were supervised and controlled by the USAF, by agreement with the Canadian and Danish Governments.
Red Cliff Air Station was a General Surveillance Radar station. The remains of which are located 5.8 miles (9.3 km) north-northeast of St. John's, Newfoundland and Labrador, Canada. It was closed in 1961.
Canadian Forces Station Beaverlodge is a closed General Surveillance Radar station. It is located 4.9 miles (7.9 km) east-northeast of Beaverlodge, Alberta. It was closed in 1988.
Canadian Forces Station Beausejour is a closed General Surveillance Radar station. It is located 45.1 miles (72.6 km) east-northeast of Winnipeg, Manitoba. It was closed in 1986.
Canadian Forces Station Kamloops is a closed General Surveillance Radar station. It is located 12.8 miles (20.6 km) northeast of Kamloops, British Columbia on the peak of Mount Lolo. It was closed in 1988 due to advances in military technology which made it obsolete.
The Motorola AN/FPS-23 was a short-range early warning radar deployed on the Distant Early Warning Line. It was used as a "gap filler", looking for aircraft attempting to sneak by the DEW line by flying between the main AN/FPS-19 stations at low altitude. It could detect aircraft flying at 200 feet over land or 50 feet over water. The system was known as Fluttar during its development at the Lincoln Laboratory, and this name was widely used for the production units as well. It was also sometimes known as "Type F". The system went into operation in 1957.
DYE Stations were Distant Early Warning Line sites of the DEW Line eastern extension in Arctic North America in Greenland and Iceland. DYE Stations were equipped with the 600 MHz AN/FPS-30 long-range radar within geodesic domes of about 60 feet diameter. Crews were regularly supplied and rotated by C-130 aircraft of the 109th Airlift Wing (NYANG) staging through Sondrestrom Air Base.
Mid-Canada Line Site 070 Kempis was a part of the Mid-Canada Line air defence network. During the late 1950s, the Mid-Canada Line (MCL) was developed as a secondary line of detection in case enemy aircraft penetrated the Distant Early Warning Line. This consisted of approximately 90 unmanned sites and eight Sector Control Stations located along the 55th parallel. Each site sent out a radio beam to its neighbouring site. If an aircraft interrupted the beam, an intruder alarm would sound.
Mid-Canada Line Site 060 Relay was a part of the Mid-Canada Line air defence network. During the late 1950s, the Mid-Canada Line (MCL) was developed as a secondary line of detection in case enemy aircraft penetrated the Distant Early Warning Line. This consisted of approximately 90 unmanned sites and eight Sector Control Stations located along the 55th parallel. Each site sent out a radio beam to its neighbouring site. If an aircraft interrupted the beam, an intruder alarm would sound.
Pole Vault was the first operational tropospheric scatter communications system. It linked radar sites and military airfields in Greenland and eastern Canada by telephone to send aircraft tracking and warning information across North America. The line stretched from Thule Air Force Base in northern Greenland, to Baffin Island and then along the eastern coast of Labrador and Newfoundland to St. John's for connection into existing commercial telecommunications networks.
Royal Canadian Air Force