Misplaced Pages

Boeing E-6 Mercury

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.

A radio repeater is a combination of a radio receiver and a radio transmitter that receives a signal and retransmits it, so that two-way radio signals can cover longer distances. A repeater sited at a high elevation can allow two mobile stations, otherwise out of line-of-sight propagation range of each other, to communicate. Repeaters are found in professional, commercial, and government mobile radio systems and also in amateur radio .

#610389

93-822: The Boeing E-6 Mercury (formerly Hermes ) is an airborne command post and communications relay based on the Boeing 707-300 . The original E-6A manufactured by Boeing's defense division entered service with the United States Navy in July 1989, replacing the EC-130Q . This platform, now modified to the E-6B standard, conveys instructions from the National Command Authority to fleet ballistic missile submarines (see communication with submarines ),

186-679: A Private Finance Initiative with newly purchased Sikorsky S-92 and AgustaWestland AW189 aircraft. The new contract means that all UK SAR coverage is now provided by Bristow aircraft. In 2018, the RAF's vision of a future constellation of imagery satellites was initiated through the launch of the Carbonite-2 technology demonstrator. The 100 kg Carbonite-2 uses commercial off-the-shelf (COTS) components to deliver high-quality imagery and 3D video footage from space. The Royal Air Force celebrated its 100th anniversary on 1 April 2018. It marked

279-637: A wing commander and, for a fast-jet squadron, have an complement of around twelve aircraft. Independent flights are so designated because they are explicitly smaller in size than a squadron. Many independent flights are, or have been, front-line flying units. For example, No. 1435 Flight carries out air defence duties for the Falkland Islands , with four Eurofighter Typhoon fighters based at RAF Mount Pleasant . Support capabilities are provided by several specialist wings and other units. Command, control, and support for overseas operations

372-549: A convenience. In a communications satellite , a transponder serves a similar function, but the transponder does not necessarily demodulate the relayed signals. A repeater is an automatic radio-relay station, usually located on a mountain top, tall building, or radio tower. It allows communication between two or more bases, mobile or portable stations that are unable to communicate directly with each other due to distance or obstructions between them. The repeater receives on one radio frequency (the "input" frequency), demodulates

465-426: A dispatching office. Modern amateur radios sometimes include cross-band repeat capability native to the radio transceiver. In commercial systems, cross-band repeaters are sometimes used in vehicular repeaters. For example, a 150 MHz hand held may communicate to a vehicle-mounted low-power transceiver. The low-power radio repeats transmissions from the portable over the vehicle's high power mobile radio, which has

558-521: A diversity (voting) receiver site back to the diversity combining system (voting comparator). Some legacy links occur in the US 150–170 MHz band. US Federal Communications Commission rule changes did not allow 150 MHz links after the 1970s. Newer links are more often seen on 72–76 MHz (Mid-band), 450–470 MHz interstitial channels, or 900 MHz links. These links, known as fixed stations in US licensing, typically connect an equipment site with

651-644: A minor role in the Korean War , with flying boats taking part. From 1953 to 1956 the RAF Avro Lincoln squadrons carried out anti- Mau Mau operations in Kenya using its base at RAF Eastleigh . The Suez Crisis in 1956 saw a large RAF role, with aircraft operating from RAF Akrotiri and RAF Nicosia on Cyprus and RAF Luqa and RAF Hal Far on Malta as part of Operation Musketeer . The RAF suffered its most recent loss to an enemy aircraft during

744-604: A mission known as TACAMO ("Take Charge And Move Out"). The E-6B model deployed in October 1998 has the ability to remotely control Minuteman ICBMs using the Airborne Launch Control System . The E-6B replaced Air Force EC-135Cs in the Looking Glass role, providing command and control of U.S. nuclear forces should ground-based control become inoperable. With production lasting until 1991,

837-408: A much longer range. In these systems, the hand-held works so long as it is within range of the low power mobile repeater. The mobile radio is usually on a different band than the hand-held to reduce the chances of the mobile radio transmitter interfering with the transmission from the hand-held to the vehicle. There is a difficult engineering problem with these systems. If you get two vehicle radios at

930-446: A part of government trunked radio systems. If one community is on a trunked system and the neighboring community is on a conventional system, a talk group or agency-fleet-subfleet may be designated to communicate with the other community. In an example where the community is on 153.755 MHz, transmitting on the trunked system talk group would repeat on 153.755 MHz. Signals received by a base station on 153.755 MHz would go over

1023-620: A quarter of Bomber Command's personnel were Canadian. Additionally, the Royal Australian Air Force represented around nine per cent of all RAF personnel who served in the European and Mediterranean theatres. During the Battle of Britain in 1940, the RAF defended the skies over Britain against the numerically superior German Luftwaffe . In what is perhaps the most prolonged and complicated air campaign in history,

SECTION 10

#1732790699611

1116-594: A single Hawker Tempest F.6 in January 1949. Before Britain developed its own nuclear weapons , the RAF was provided with American nuclear weapons under Project E . However, following the development of its own arsenal, the British Government elected on 16 February 1960 to share the country's nuclear deterrent between the RAF and submarines of the Royal Navy, first deciding to concentrate solely on

1209-423: A single antenna and a device called a duplexer . The device is a tuned filter connected to the antenna. In this example, consider a type of device called a band-pass duplexer . It allows, or passes, a band, (or a narrow range,) of frequencies. There are two legs to the duplexer filter, one is tuned to pass the input frequency, the other is tuned to pass the output frequency. Both legs of the filter are coupled to

1302-466: A single antenna. Devices called receiver multicouplers split the signal from the antenna into many receiver connections. The multicoupler amplifies the signals reaching the antenna, then feeds them to several receivers, attempting to make up for losses in the power dividers (or splitters). These operate similarly to a cable TV splitter but must be built to higher quality standards so they work in environments where strong interfering signals are present. On

1395-447: A single trunked system may be located at the same site. (Some architectures such as iDEN sites may have more than 29 repeaters.) In a shared system, a receive antenna is usually located at the top of the antenna tower. Putting the receive antenna at the top helps to capture weaker received signals than if the receive antenna were lower of the two. By splitting the received signal from the antenna, many receivers can work satisfactorily from

1488-626: A support enabler role. A Control and Reporting Centre (CRC) at RAF Boulmer is tasked with compiling a Recognised Air Picture of UK air space and providing tactical control of the Quick Reaction Alert Force . In order to achieve this Boulmer is supported by a network of eight Remote Radar Heads (RRHs) spread the length of the UK. The UK operates permanent military airfields (known as Permanent Joint Operating Bases) in four British Overseas Territories . These bases contribute to

1581-488: A system that covers a large area and works with the weak signal levels of hand-held radios. Some models of radio signals suggest that the transmitters of hand-held radios create received signals at the base station one to two orders of magnitude (10 to 20 decibels or 10 to 100 times) weaker than a mobile radio with a similar transmitter output power. Radio repeaters are typically placed in locations which maximize their effectiveness for their intended purpose: Popular mainly in

1674-490: A war that remained under low profile. The Konfrontasi against Indonesia in the early 1960s did see use of RAF aircraft, but due to a combination of deft diplomacy and selective ignoring of certain events by both sides, it never developed into a full-scale war. The RAF played a large role in the Aden Emergency between 1963 and 1967. Hawker Hunter FGA.9s based at RAF Khormaksar , Aden , were regularly called in by

1767-999: Is also responsible for the RAF Medical Services, RAF Support Force, consisting of the RAF's engineering, logistics, intelligence, signals, musical and mountain rescue assets, RAF's Combat and Readiness Force, comprising the RAF Regiment , and the Air Security Force, comprising RAF Police . It oversees stations at RAF Benson and RAF Brize Norton in Oxfordshire, RAF Henlow in Bedfordshire, RAF Honington in Suffolk, RAF Odiham in Hampshire and RAF Northolt in West London. No. 11 Group

1860-429: Is another. A repeater with an input of 33.980 MHz and an output of 46.140 MHz is a same band repeater. In same band repeaters, a central design problem is keeping the repeater's own transmitter from interfering with the receiver. Reducing the coupling between transmitter and input frequency receiver is called isolation . In same-band repeaters, isolation between transmitter and receiver can be created by using

1953-501: Is at RAF High Wycombe co-located with Air Command. Groups are the subdivisions of operational commands and are responsible for certain types of capabilities or for operations in limited geographical areas. There are five groups subordinate to Air Command, of which four are functional and one is geographically focused: No. 1 Group is responsible for combat aircraft (comprising the Lightning Force and Typhoon Force) and

SECTION 20

#1732790699611

2046-470: Is made easier by maximizing, as much as possible, the separation between input and output frequencies. When operating through a repeater, mobile stations must transmit on a different frequency than the repeater output. Although the repeater site must be capable of simultaneous reception and transmission (on two different frequencies), mobile stations can operate in one mode at a time, alternating between receiving and transmitting; so, mobile stations do not need

2139-814: Is part of the Ministry of Defence and body legally responsible for the defence of the United Kingdom and its overseas territories . The Chief of the Air Staff chairs the Air Force Board Standing Committee (AFBSC) which decides on the policy and actions required for the RAF to meet the requirements of the Defence Council and His Majesty's Government . The Chief of the Air Staff is supported by several other senior commanders: Administrative and operational command of

2232-657: Is responsible for integrating operations across the air , cyber and space domains whilst responding to new and evolving threats. It includes the RAF's Battlespace Management Force which controls the UK Air Surveillance and Control System (ASACS). The group oversees stations at RAF Boulmer in Northumberland, RAF Fylingdales in North Yorkshire and RAF Spadeadam in Cumbria. No. 22 Group

2325-731: Is responsible for the supply of qualified and skilled personnel to the RAF and provides flying and non-flying training to all three British armed services. It is the end-user of the UK Military Flying Training System which is provided by civilian contractor Ascent Flight Training . The group oversees stations at RAF College Cranwell in Lincolnshire, RAF Cosford and RAF Shawbury in Shropshire, RAF Halton in Buckinghamshire, MOD St Athan in

2418-592: Is second to none, and that makes a decisive air power contribution in support of the UK Defence Mission". The mission statement is supported by the RAF's definition of air power , which guides its strategy. Air power is defined as "the ability to project power from the air and space to influence the behaviour of people or the course of events". Today, the Royal Air Force maintains an operational fleet of various types of aircraft, described by

2511-517: Is typically provided through Expeditionary Air Wings (EAWs). Each wing is brought together as and when required and comprises the deployable elements of its home station as well as other support elements from throughout the RAF. Several Expeditionary Air Wings are based overseas: The RAF Schools consist of the squadrons and support apparatus that train new aircrew to join front-line squadrons. The schools separate individual streams, but group together units with similar responsibility or that operate

2604-643: The 1948 Arab–Israeli War : during the withdrawal of the former Mandatory Palestine in May 1948 where British Supermarine Spitfire FR.18s shot down four Royal Egyptian Air Force Spitfire LF.9s after the REAF mistakenly attacked RAF Ramat David airbase; and during encounters with the Israeli Air Force which saw the loss of a single de Havilland Mosquito PR.34 in November 1948 and four Spitfire FR.18s and

2697-653: The British Army as close air support to carry out strikes on rebel positions. The Radfan Campaign (Operation Nutcracker) in early 1964 was successful in suppressing the revolt in Radfa, however it did nothing to end the insurgency with the British withdrawing from Aden in November 1967. One of the largest actions undertaken by the RAF during the Cold War was the air campaign during the 1982 Falklands War , in which

2790-647: The British Empire , including establishing bases to protect Singapore and Malaya. The RAF's naval aviation branch, the Fleet Air Arm , was founded in 1924 but handed over to Admiralty control on 24 May 1939. The RAF adopted the doctrine of strategic bombing , which led to the construction of long-range bombers and became its main bombing strategy in the Second World War . The Royal Air Force underwent rapid expansion prior to and during

2883-765: The E-3D Sentry aircraft that had been in service with the Royal Air Force was purchased for conversion into a dedicated E-6 trainer. This was done as a means to extend the life of the operational fleet by reducing the need for E-6s to be used for training missions. In 2015, both the Air Force and Navy realized that they needed new aircraft to serve the missions of both the E-4 and the E-6. At one point, they considered building one plane to replace both aircraft, but by 2020,

Boeing E-6 Mercury - Misplaced Pages Continue

2976-678: The London Eye , the RAF Memorial and (at 13.00) the Ministry of Defence building . Four major defence reviews have been conducted since the end of the Cold War: the 1990 Options for Change , the 1998 Strategic Defence Review , the 2003 Delivering Security in a Changing World and the 2010 Strategic Defence and Security Review (SDSR). All four defence reviews have resulted in steady reductions in manpower and numbers of aircraft, especially combat aircraft such as fast-jets. As part of

3069-659: The Royal Naval Air Service (RNAS). This was done as recommended in a report prepared by the South African statesman and general Jan Smuts . At that time it was the largest air force in the world. Its headquarters was located in the former Hotel Cecil . After the war, the RAF was drastically cut and its inter-war years were relatively quiet. The RAF was put in charge of British military activity in Iraq , and carried out minor activities in other parts of

3162-741: The Royal Navy 's Fleet Air Arm and the British Army 's Army Air Corps also operate armed aircraft. The Royal Air Force was formed towards the end of the First World War on 1 April 1918, becoming the third independent air force in the world after the Mexican Air Force (established 5 February 1915) and the Finnish Air Force (established 6 March 1918), by merging the Royal Flying Corps (RFC) and

3255-417: The UK Military Flying Training System which is dedicated to training aircrew for all three UK armed services. Specialist ground crew training is focused at RAF Cosford , RAF St Mawgan and MOD St. Athan . Operations are supported by numerous other flying and non-flying stations, with activity focussed at RAF Honington which coordinates Force Protection and RAF Leeming & RAF Wittering which have

3348-631: The United States Air Force , the RAF formed its own RPAS squadron in 2007 when No. 39 Squadron was stood up as a General Atomics MQ-9A Reaper unit at Creech AFB , Nevada. The RAF's 90th anniversary was commemorated on 1 April 2008 by a flypast of the RAF's Aerobatic Display Team the Red Arrows and four Eurofighter Typhoons along the River Thames , in a straight line from just south of London City Airport Tower Bridge,

3441-740: The Westland Puma HC2 for search and rescue. No. 230 Squadron , based at Medicina Lines , Brunei, also operate the Puma HC2. A flying squadron is an aircraft unit which carries out the primary tasks of the RAF. RAF squadrons are somewhat analogous to the regiments of the British Army in that they have histories and traditions going back to their formation, regardless of where they are based or which aircraft they are operating. They can be awarded standards and battle honours for meritorious service. Most flying squadrons are commanded by

3534-578: The 1960s. Historic examples of cross-band systems include: In commercial systems, manufacturers stopped making cross band mobile radio equipment with acceptable specifications for public safety systems in the early 1980s. At the time, some systems were dismantled because new radio equipment was not available. Sporadic E ionospheric ducting can make the 46 MHz and below frequencies unworkable in summer. For decades, cross-band repeaters have been used as fixed links. The links can be used for remote control of base stations at distant sites or to send audio from

3627-708: The 1991 Gulf War , the 1999 Kosovo War , the 2001 War in Afghanistan , the 2003 invasion and war in Iraq , the 2011 intervention in Libya and from 2014 onwards has been involved in the war against the Islamic State . The RAF began conducting Remotely-piloted Air System (RPAS) operations in 2004, with No. 1115 Flight carrying out missions in Afghanistan and Iraq with the General Atomics MQ-1 Predator . Initially embedded with

3720-547: The Battle of Britain contributed significantly to the delay and subsequent indefinite postponement of Operation Sea Lion , Hitler's plans for an invasion of the UK. In the House of Commons on 20 August, prompted by the ongoing efforts of the RAF, Prime Minister Winston Churchill made a speech to the nation, where he said " Never in the field of human conflict was so much owed by so many to so few" . The largest RAF effort during

3813-569: The Berlin Blockade take place. As part of Operation Pitting , the RAF helped evacuate over 15,000 people in two weeks. Between April and May 2023, the RAF helped evacuate over 2,300 people from Sudan due to the 2023 Sudan conflict as part of Operation Polarbear . In April 2024, Typhoon FGR4s operating from RAF Akrotiri, Cyprus, engaged and destroyed Iranian drones over Iraqi and Syrian airspace during Iran's strikes against Israel . The professional head and highest-ranking officer of

Boeing E-6 Mercury - Misplaced Pages Continue

3906-570: The British Ministry of Defence (MOD), which are to "provide the capabilities needed to ensure the security and defence of the United Kingdom and overseas territories, including against terrorism; to support the Government's foreign policy objectives particularly in promoting international peace and security". The RAF describes its mission statement as "... [to provide] an agile, adaptable and capable Air Force that, person for person,

3999-635: The E-6 is United States Strategic Command 's (USSTRATCOM) Airborne Command Post (ABNCP). It is designed to take over in case the Global Operations Center (GOC), located at Offutt Air Force Base , Nebraska , is destroyed or incapable of communicating with strategic forces. The term "Looking Glass" is used because the ABNCP "mirrors" the abilities of the US Strategic Command GOC to control nuclear forces. The E-6A, which

4092-650: The E-6 was the final new derivative of the Boeing 707 to be built. Like the E-3 Sentry Airborne Warning and Control System aircraft, the E-6 is adapted from Boeing's 707-320 airliner. Rolled out at Boeing's Renton Factory in December 1986, the first E-6 made its maiden flight in February 1987, when it was flown to nearby Boeing Field in south Seattle for fitting of mission avionics. It

4185-521: The E-6B standard, with the final delivery taking place in December 2006. The E-6 cannot use the probe-and-drogue in-flight refueling method that most other US Navy aircraft use. It uses a flying boom receptacle on the upper-forward fuselage, making it, like the Navy's Boeing P-8 Poseidon aircraft, reliant upon specific U.S. Air Force aircraft ( KC-135 Stratotanker , KC-10 Extender , and KC-46 Pegasus ) for in-flight refueling. Codenamed Looking Glass ,

4278-673: The Houses of Parliament, Conservative MP and Minister of State for the Armed Forces , Andrew Robathan , announced that the RAF's QRA force had been scrambled almost thirty times in the last three years: eleven times during 2010, ten times during 2011 and eight times during 2012. RAF Coningsby in Lincolnshire and RAF Lossiemouth in Moray both provide QRA aircraft, and scramble their Typhoons within minutes to meet or intercept aircraft which give cause for concern. Lossiemouth generally covers

4371-456: The Navy decided to go its own way and develop an aircraft specifically for the TACAMO mission, under the E-XX TACAMO program. The Air Force independently pursued an E-4 replacement under the Survivable Airborne Operations Center program. The Navy selected a variant of the Lockheed EC-130J , specifically one derived from the lengthened C-130J-30 . Initial orders were placed in late 2020 with development beginning in earnest in 2022. Delivery of

4464-421: The RAF as being "leading-edge" in terms of technology. This largely consists of fixed-wing aircraft, including those in the following roles: fighter and strike , airborne early warning and control , intelligence, surveillance, target acquisition, and reconnaissance (ISTAR), signals intelligence (SIGINT), maritime patrol, air-to-air refueling (AAR) and strategic & tactical transport . The majority of

4557-410: The RAF emerged as the largest air force in the world at the time. Since its formation, the RAF has played a significant role in British military history . In particular, during the Second World War , the RAF established air superiority over Nazi Germany 's Luftwaffe during the Battle of Britain , and led the Allied strategic bombing effort. The RAF's mission is to support the objectives of

4650-508: The RAF is delegated by the Air Force Board to Headquarters Air Command , based at RAF High Wycombe in Buckinghamshire . Air Command was formed on 1 April 2007 by combining RAF Strike Command and RAF Personnel and Training Command , resulting in a single command covering the whole RAF, led by the Chief of the Air Staff. Through its subordinate groups , Air Command oversees the whole spectrum of RAF aircraft and operations. United Kingdom Space Command (UKSC), established 1 April 2021 under

4743-408: The RAF operated alongside the Fleet Air Arm . During the war, RAF aircraft were deployed in the mid-Atlantic at RAF Ascension Island and a detachment from No. 1 Squadron was deployed with the Royal Navy, operating from the aircraft carrier HMS Hermes . RAF pilots also flew missions using the Royal Navy's Sea Harriers in the air-to-air combat role, in particular Flight Lieutenant Dave Morgan

SECTION 50

#1732790699611

4836-546: The RAF's intelligence, surveillance, target acquisition, and reconnaissance (ISTAR) capabilities. It oversees stations at RAF Coningsby and RAF Waddington in Lincolnshire, RAF Lossiemouth in Moray and RAF Marham in Norfolk. The group's Eurofighter Typhoon FGR4 aircraft protect UK and NATO airspace by providing a continuous Quick Reaction Alert capability. No. 2 Group controls the Air Mobility Force which provides strategic and tactical airlift , air-to-air refuelling and command support air transport (CSAT). The group

4929-427: The RAF's rotary-wing aircraft form part of the tri-service Joint Aviation Command in support of ground forces. Most of the RAF's aircraft and personnel are based in the UK, with many others serving on global operations (principally over Iraq and Syria ) or at long-established overseas bases ( Ascension Island , Cyprus , Gibraltar , and the Falkland Islands ). Although the RAF is the principal British air power arm,

5022-401: The Royal Air Force is the Chief of the Air Staff (CAS). He reports to the Chief of the Defence Staff , who is the professional head of the British Armed Forces . The incumbent Chief of the Air Staff is Air Chief Marshal Sir Richard Knighton who was appointed in 2023. The management of the RAF is the responsibility of the Air Force Board , a sub-committee of the Defence Council which

5115-478: The Second World War. Under the British Commonwealth Air Training Plan of December 1939, the air forces of British Commonwealth countries trained and formed " Article XV squadrons " for service with RAF formations. Many individual personnel from these countries, and exiles from occupied Europe , also served with RAF squadrons. By the end of the war the Royal Canadian Air Force had contributed more than 30 squadrons to serve in RAF formations, similarly, approximately

5208-423: The Suez Crisis, when an English Electric Canberra PR7 was shot down over Syria . In 1957, the RAF participated heavily during the Jebel Akhdar War in Oman, operating both de Havilland Venom and Avro Shackleton aircraft. The RAF made 1,635 raids, dropping 1,094 tons and firing 900 rockets at the interior of Oman between July and December 1958, targeting insurgents, mountain top villages and water channels in

5301-417: The UK, community based radio systems usually consist of a community radio repeater (similar to a ham repeater ), for use by the community and businesses often used for Civic Events , Shopwatch , PubWatch , Neighborhood Watch and Community engagement . In larger towns, separate systems are typically used, separating commercial and community use. Whereas in smaller towns, single systems are typically used by

5394-421: The United States and works in close cooperation with the U.S. Air Force in the development of the Lockheed Martin F-35B Lightning . No. 80 Squadron is part of the Australia, Canada and United Kingdom Reprogramming Laboratory (ACURL) at Eglin Air Force Base , Florida, and is tasked with compiling and testing the Mission Data File Sets (MDFS) for the F-35. No. 84 Squadron is located at RAF Akrotiri, operating

5487-578: The Vale of Glamorgan, RAF St Mawgan in Cornwall and RAF Valley on Anglesey. The No. 22 Group also manages the Royal Air Force Air Cadets . An RAF station is ordinarily subordinate to a group and is commanded by a group captain . Each station typically hosts several flying and non-flying squadrons or units which are supported by administrative and support wings. Front-line flying operations are focused at eight stations: Flying training takes places at RAF Barkston Heath , RAF College Cranwell , RAF Shawbury and RAF Valley , each forming part of

5580-439: The air force's V bomber fleet. These were initially armed with nuclear gravity bombs , later being equipped with the Blue Steel missile . Following the development of the Royal Navy's Polaris submarines , the strategic nuclear deterrent passed to the navy's submarines on 30 June 1969. With the introduction of Polaris, the RAF's strategic nuclear role was reduced to a tactical one, using WE.177 gravity bombs. This tactical role

5673-422: The antenna. The repeater receiver is connected to the receive leg while the transmitter is connected to the transmit leg. The duplexer prevents degradation of the receiver sensitivity by the transmitter in two ways. First, the receive leg greatly attenuates the transmitter's carrier at the receiver input (typically by 90-100 dB), preventing the carrier from overloading (blocking) the receiver front end. Second,

SECTION 60

#1732790699611

5766-494: The arrival of jet fighters and bombers. During the early stages of the Cold War, one of the first major operations undertaken by the RAF was the Berlin Airlift , codenamed Operation Plainfire. Between 26 June 1948 and the lifting of the Russian blockade of the city on 12 May 1949, the RAF provided 17% of the total supplies delivered, using Avro Yorks , Douglas Dakotas flying to Gatow Airport and Short Sunderlands flying to Lake Havel. The RAF saw its first post-war engagements in

5859-568: The bulky, and costly filters required at a repeater site. Mobile stations may have an option to select a "talk around" mode to transmit and receive on the same frequency; this is sometimes used for local communication within range of the mobile units. There is no set rule about spacing of input and output frequencies for all radio repeaters. Any spacing where the designer can get sufficient isolation between receiver and transmitter will work. In some countries, under some radio services, there are agreed-on conventions or separations that are required by

5952-414: The command of Air Vice-Marshal Paul Godfrey is a joint command, but sits "under the Royal Air Force." Godfrey is of equal rank to the commanders of 1, 2, 11, and 22 Groups. The new command has "responsibility for not just operations, but also generating, training and growing the force, and also owning the money and putting all the programmatic rigour into delivering new ..capabilities." UKSC headquarters

6045-463: The decline of the British Empire, global operations were scaled back, and RAF Far East Air Force was disbanded on 31 October 1971. Despite this, the RAF fought in many battles in the Cold War period. In June 1948, the RAF commenced Operation Firedog against Malayan pro-independence fighters during the Malayan Emergency . Operations continued for the next 12 years until 1960 with aircraft flying out of RAF Tengah and RAF Butterworth . The RAF played

6138-586: The first aircraft is expected in FY26. The Navy expects the E-6 to fulfill the TACAMO role into the 2030s as the E-XX is transitioned into service. In October 2024, the replacement aircraft was officially named E-130J . Data from Jane's all the world's aircraft, 1992–93 The US Navy – Fact File: E-6B Mercury Airborne Command Post General characteristics Performance Avionics Related development Aircraft of comparable role, configuration, and era Related lists Radio repeater Repeater systems use two different radio frequencies;

6231-569: The first hint of something abnormal, a controller has the option to put them on a higher level of alert, 'a call to cockpit'. In this scenario the pilot races to the hardened aircraft shelter and does everything short of starting his engines". On 4 October 2015, a final stand-down saw the end of more than 70 years of RAF Search and Rescue provision in the UK. The RAF and Royal Navy's Westland Sea King fleets, after over 30 years of service, were retired. A civilian contractor, Bristow Helicopters , took over responsibility for UK Search and Rescue, under

6324-402: The great bulk of the RAF's bombing campaign, mainly due to Harris, but it also developed precision bombing techniques for specific operations, such as the infamous "Dambusters" raid by No. 617 Squadron , or the Amiens prison raid known as Operation Jericho . Following victory in the Second World War, the RAF underwent significant re-organisation, as technological advances in air warfare saw

6417-462: The highest scoring pilot of the war. Following a British victory, the RAF remained in the South Atlantic to provide air defence to the Falkland Islands, with the McDonnell Douglas Phantom FGR2 based at RAF Mount Pleasant which was built in 1984. With the end of the Cold War and the collapse of the Soviet Union, the RAF's focus returned to expeditionary air power . Since 1990, the RAF has been involved in several large-scale operations, including

6510-567: The latest 2010 Strategic Defence and Security Review, the BAE Systems Nimrod MRA4 maritime patrol aircraft was cancelled due to over spending and missing deadlines. Other reductions saw total manpower reduced by 5,000 personnel to a trained strength of 33,000 and the early retirement of the Joint Force Harrier aircraft, the BAE Harrier GR7/GR9 . In recent years, fighter aircraft on Quick Reaction Alert (QRA) have been increasingly required to scramble in response to Russian Air Force aircraft approaching British airspace. On 24 January 2014, in

6603-498: The mobiles transmit on one frequency, and the repeater station receives those transmission and transmits on a second frequency. Since the repeater must transmit at the same time as the signal is being received, and may even use the same antenna for both transmitting and receiving, frequency-selective filters are required to prevent the receiver from being overloaded by the transmitted signal. Some repeaters use two different frequency bands to provide isolation between input and output or as

6696-431: The northern sector of UK airspace, while Coningsby covers the southern sector. Typhoon pilot Flight Lieutenant Noel Rees describes how QRA duty works. "At the start of the scaled QRA response, civilian air traffic controllers might see on their screens an aircraft behaving erratically, not responding to their radio calls, or note that it's transmitting a distress signal through its transponder. Rather than scramble Typhoons at

6789-478: The occasion on 10 July 2018 with a flypast over London consisting of 103 aircraft. Between March 2020 and 2022, the RAF assisted with the response efforts to the COVID-19 pandemic in the United Kingdom as part of Operation Rescript . This saw the service provide repatriation flights and aeromedical evacuations of COVID-19 patients, drivers and call-handlers to support ambulance services and medics to assist with

6882-495: The output of the combining circuit. Part of this loss can be made up with increased antenna gain. Fifty watts of transmitter power to the antenna will make a received signal strength at a distant mobile radio that is almost identical to 100 watts. In trunked systems with many channels, a site design may include several transmit antennas to reduce combining network losses. For example, a six-channel trunked system may have two transmit antennas with three transmitters connected to each of

6975-499: The physical defence and maintenance of sovereignty of the British Overseas Territories and enable the UK to conduct expeditionary military operations . Although command and oversight of the bases is provided by Strategic Command , the airfield elements are known as RAF stations. Four RAF squadrons are based overseas. No. 17 Test and Evaluation Squadron is based at Edwards Air Force Base , California, in

7068-413: The repeater's own transmitter from degrading the repeater receiver. If the repeater transmitter and receiver are not isolated well, the repeater's own transmitter desensitizes the repeater receiver. The problem is similar to being at a rock concert and not being able to hear the weak signal of a conversation over the much stronger signal of the band. In general, isolating the receiver from the transmitter

7161-419: The same aircraft type. Some schools operate with only one squadron, and have an overall training throughput which is relatively small; some, like No. 3 Flying Training School , have responsibility for all Elementary Flying Training (EFT) in the RAF, and all RAF aircrew will pass through its squadrons when they start their flying careers. No. 2 Flying Training School and No. 6 Flying Training School do not have

7254-430: The same location, some protocol has to be established so that one portable transmitting doesn't activate two or more mobile radio transmitters. Motorola uses a hierarchy system with PAC*RT, each repeater transmits a tone when it is turned on, so the last one on site that turns on is the one that gets used. This is so several of them are not on at once. Vehicular repeaters are complex but can be less expensive than designing

7347-407: The same time. Transmitter combining systems are lossy. As a rule of thumb, each leg of the combiner has a 50% (3 decibel) power loss. If two transmitters are connected to a single antenna through a combiner, half of their power will reach the combiner output. (This assumes everything is working properly.) If four transmitters are coupled to one antenna, a quarter of each transmitter's power will reach

7440-419: The signal, and simultaneously re-transmits the information on its "output" frequency. All stations using the repeater transmit on the repeater's input frequency and receive on its output frequency. Since the repeater is usually located at an elevation higher than the other radios using it, their range is greatly extended. Because the transmitter and receiver are on at the same time, isolation must exist to keep

7533-475: The staffing of hospitals, testing units and vaccination centres. Under Operation Broadshare , the RAF has also been involved with COVID-19 relief operations overseas, repatriating stranded nationals and delivering medical supplies and vaccines to British Overseas Territories and military installations. The UK's 20-year long operations in Afghanistan came to an end in August 2021, seeing the largest airlift since

7626-474: The system license. In the case of input and output frequencies in the United States, for example: These are just a few examples. There are many other separations or spacings between input and output frequencies in operational systems. Same band repeaters operate with input and output frequencies in the same frequency band. For example, in US two-way radio, 30–50 MHz is one band and 150–174 MHz

7719-471: The systems is simplex, the repeater must have logic preventing transmitter keying in both directions at the same time. Voting comparators with a transmitter keying matrix are sometimes used to connect incompatible base stations. In looking at records of old systems, examples of cross-band commercial systems were found in every U.S. radio service where regulations allowed them. In California, specific systems using cross-band repeaters have existed at least since

7812-423: The transmit antenna below, and along the centerline of, the receive antenna. Several transmitters can be connected to the same antenna using filters called combiners . Transmitters usually have directional devices installed along with the filters that block any reflected power in the event the antenna malfunctions. The antenna must have a power rating that will handle the sum of energy of all connected transmitters at

7905-554: The transmit leg attenuates the transmitter broadband noise on the receiver frequency, also typically by 90-100 dB. By virtue of the transmitter and receiver being on different frequencies, they can operate at the same time on a single antenna. There is often not enough tower space to accommodate a separate antenna for each repeater at crowded equipment sites. In same-band repeaters at engineered, shared equipment sites, repeaters can be connected to shared antenna systems. These are common in trunked systems , where up to 29 repeaters for

7998-421: The transmitter side, a second transmit antenna is installed somewhere below the receive antenna. There is an electrical relationship defined by the distance between transmit and receive antennas. A desirable null exists if the transmit antenna is located exactly below the receive antenna beyond a minimum distance. Almost the same isolation as a low-grade duplexer (about −60 decibels) can be accomplished by installing

8091-468: The trunked system on an assigned talk group. In conventional government systems, cross band repeaters are sometimes used to connect two agencies who use radio systems on different bands. For example, a fire department in Colorado was on a 46 MHz channel while a police department was on a 154 MHz channel, they built a cross-band repeater to allow communication between the two agencies. If one of

8184-467: The two transmit antennas. Because small variations affect every antenna, each antenna will have a slightly different directional pattern. Each antenna will interact with the tower and other nearby antennas differently. If one were to measure received signal levels, this would cause a variation among channels on a single trunked system. Variations in signal strength among channels on one trunked system can also be caused by: Cross-band repeaters are sometimes

8277-555: The war was the strategic bombing campaign against Germany by Bomber Command. While RAF bombing of Germany began almost immediately upon the outbreak of war at first it was ineffectual; it was only later, particularly under the leadership of Air Chief Marshal Harris , that these attacks became increasingly devastating, from early 1943 onward, as new technology and greater numbers of superior aircraft became available. The RAF adopted night-time area bombing on German cities such as Hamburg and Dresden . Night time area bombing constituted

8370-601: The whole community. Royal Air Force The Royal Air Force ( RAF ) is the air and space force of the United Kingdom , British Overseas Territories and Crown Dependencies . It was formed towards the end of the First World War on 1 April 1918, on the merger of the Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS). Following the Allied victory over the Central Powers in 1918,

8463-666: Was continued by the V bombers into the 1980s and until 1998 by the Panavia Tornado GR1 . For much of the Cold War the primary role of the RAF was the defence of Western Europe against potential attack by the Soviet Union , with many squadrons based in West Germany . The main RAF bases in RAF(G) were RAF Brüggen , RAF Gutersloh , RAF Laarbruch and RAF Wildenrath – the only air defence base in RAF(G). With

8556-516: Was delivered to the Navy for testing in July 1988. The E-6B is an upgrade of the E-6A. It includes a battlestaff area and updated mission equipment. The flight deck systems were later replaced with an off-the-shelf 737 Next Generation cockpit. This greatly increases the situational awareness of the pilot and saves significant cost over the previous custom avionics package. The first E-6B was accepted in December 1997. All 16 E-6A aircraft were modified to

8649-601: Was initially named Hermes , entered service with squadron VQ-3 in August 1989. A second squadron, VQ-4 , received its first E-6As in January 1991, allowing the EC-130Q to be phased out in June 1991. The E-6A was renamed Mercury in autumn 1991 by request of the Navy. Sixteen E-6A planes were delivered from 1988 to 1992. The E-6 fleet is based at Tinker Air Force Base , Oklahoma , and operated by Fleet Air Reconnaissance Squadron 3 (VQ-3) , VQ-4 , and VQ-7. In 2021, one of

#610389