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Tropospheric scatter

Tropospheric scatter

Overview
Tropospheric scatter is a method of transmitting and receiving microwave radio signals over considerable distances – often up to 300 km. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at particular frequencies are randomly scattered as they pass through the upper layers of the troposphere
Troposphere
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....

 (hence troposcatter). Radio signals are transmitted in a tight beam aimed at the tropopause
Tropopause
The tropopause is the atmospheric boundary between the troposphere and the stratosphere.-Definition:Going upward from the surface, it is the point where air ceases to cool with height, and becomes almost completely dry...

, midway between the transmitter and receiver sites; as the signals pass through the troposphere they are scattered, allowing the receiver station to pick up the signal.

Normally, microwave signals, transmitted at various frequencies, usually around 12 Gigahertz (GHz) or 19 GHz, are only used for ‘line of sight
Line-of-sight propagation
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line...

’ applications, where the receiver can be ‘seen’ from the transmitter.
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Encyclopedia
Tropospheric scatter is a method of transmitting and receiving microwave radio signals over considerable distances – often up to 300 km. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at particular frequencies are randomly scattered as they pass through the upper layers of the troposphere
Troposphere
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....

 (hence troposcatter). Radio signals are transmitted in a tight beam aimed at the tropopause
Tropopause
The tropopause is the atmospheric boundary between the troposphere and the stratosphere.-Definition:Going upward from the surface, it is the point where air ceases to cool with height, and becomes almost completely dry...

, midway between the transmitter and receiver sites; as the signals pass through the troposphere they are scattered, allowing the receiver station to pick up the signal.

Normally, microwave signals, transmitted at various frequencies, usually around 12 Gigahertz (GHz) or 19 GHz, are only used for ‘line of sight
Line-of-sight propagation
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line...

’ applications, where the receiver can be ‘seen’ from the transmitter. However, tropospheric scatter signals use a frequency of around 2 GHz.

Because the troposphere is turbulent and has a high proportion of moisture the tropospheric scatter radio signals are refracted and consequently only a proportion of the radio energy is collected by the receiving antennae. Frequencies of transmission around 2 GHz are best suited for tropospheric scatter systems as at this frequency the wavelength of the signal interacts well with the moist, turbulent areas of the troposphere, improving signal to noise ratios.

High gain
High-gain antenna
A high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...

 dish or billboard antennae are required for tropospheric scatter systems as the propagation losses are very high; only about one billion-billionth (1 x 10−12) of the transmit power is available at the receiver. Typically, dish antennae with isotropic gains
Antenna gain
In electromagnetics, an antenna's power gain or simply gain is a key performance figure which combines the antenna's directivity and electrical efficiency. As a transmitting antenna, the figure describes how well the antenna converts input power into radio waves headed in a specified direction...

 of between 40 decibels(dB) and 60dB are used with transmitter powers of 1 Kilowatt(kW) to 10 kW.

Tropospheric scatter is a fairly secure method of propagation as dish alignment is critical, making it extremely difficult to intercept the signals, especially if transmitted across open water, making them highly attractive to military users. Military systems have tended to be ‘thin-line’ tropo – so called because only a narrow bandwidth ‘information’ channel was carried on the tropo system; generally up to 32 analogue (4 kHz bandwidth) channels.

Civilian troposcatter systems, such as the British Telecom(BT) North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 oil communications network required higher capacity ‘information’ channels than were available using hf (high frequency – 3 to 30 MHz) radio signals, before satellite technology was available. The BT systems, based at Scousburgh in the Shetland Islands, Mormond Hill in Aberdeenshire and Row Brow near Scarborough, were capable of transmitting and receiving 156 analogue (4 kHz bandwidth) channels of data and telephony to / from North Sea oil production platforms, using frequency division multiplexing (FDMX) to combine the channels.

Because of the nature of the turbulence in the troposphere, quadruple diversity propagation
Antenna diversity
Antenna diversity, also known as space diversity, is any one of several wireless diversity schemes that uses two or more antennas to improve the quality and reliability of a wireless link. Often, especially in urban and indoor environments, there is no clear line-of-sight between transmitter and...

 paths were used to ensure 99.98% reliability of the service, equating to about 3 minutes of downtime due to propagation drop out per month. The quadruple space and polarisation diversity systems needed two separate dish antenna (spaced several metres apart) and two differently polarised feed horn
Feed horn
In satellite dish and antenna design, a feedhorn is a small horn antenna used to convey radio waves between the transmitter and/or receiver and the reflector, particularly in parabolic antennas...

s – one using vertical polarisation, the other using horizontal polarisation. This ensured that at least one signal path was open at any one time. The signals from the four different paths were recombined in the receiver where a phase corrector removed the phase differences of each signal. Phase differences were caused by the different path lengths of each signal from transmitter to receiver. Once phase corrected, the four signals could be combined additively.


Tropospheric Scatter Communications Networks


The Tropospheric scatter phenomenon has been used to build both civilian and military communication links in a number of parts of the world, including:-
ACE High
ACE High
ACE High was a NATO communications system which dates back to 1956. The system was decommissioned in the late 1980s, and its frequencies reallocated for commercial radiotelephone service. The system was designed to be an L-band troposcatter radio system, which was meant to provide long-range...

NATO in Europe.


BT
BT Group
BT Group plc is a global telecommunications services company headquartered in London, United Kingdom. It is one of the largest telecommunications services companies in the world and has operations in more than 170 countries. Through its BT Global Services division it is a major supplier of...

 (British Telecom)
United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 - Shetland to Mormond Hill
Mormond Hill
Mormond Hill is a large hill in Aberdeenshire, Scotland not far from Fraserburgh. The villages of Strichen and New Leeds can be found at its foot hills....



PTT
PTT
PTT may refer to:Chemistry and medicine:* Partial thromboplastin time, a performance indicator in medicine for coagulation status* Photothermal Therapy, A method of using light and photosensitizers for medical treatments...

 (a Spanish telecomms company)
Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 - Nogueira
Nogueira
Nogueira, Galician and Portuguese for walnut tree, may refer to:-People:* Antônio Rodrigo "Minotauro" Nogueira , Brazilian MMA fighter...

 to Artzamendi


CNT
CNT
-Buildings:* Canadian National Tower, or CN Tower, a communications and observation tower in Toronto, Ontario, Canada-Businesses:* Cantiere Navale Triestino , an Italian shipbuilding company founded in 1908 and renamed Cantieri Riuniti dell' Adriatico Monfalcone in 1929-Non-profit organizations:*...

 (Canadian telecomms company)
Tsiigehtchic to Galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

Hay River
Hay River
-Rivers:* Hay River * Hay River , a river in Alberta and Northwest Territories, Canada* Hay River , a river in south-western Australia...

 - Port Radium - Lady Franklin Point
Lady Franklin Point
Lady Franklin Point is a landform in the Canadian Arctic territory of Nunavut. It is located on southwestern Victoria Island in the Coronation Gulf by Austin Bay at the eastern entrance of Dolphin and Union Strait....



Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

 - Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

Guanabo
Guanabo
Guanabo is a town in the Ciudad de la Habana Province of Cuba. It is located within the municipality of Habana del Este halfway between the centre of Havana and Santa Cruz del Norte, at the mouth of the Guanabo River, between the Atlantic Ocean coast and the Sierra del Canchón .Guanabo is a seaside...

 to Florida City


AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

Chatham, NC - Buckingham, VA - Charlottesville 2, VA - Leesburg 5, VA - Hagerstown 2, MD


Texas Towers
Texas Towers
The Texas Towers were a set of off-shore radar facilities used by the United States Air Force during the Cold War that were modeled on the offshore oil drilling platforms first employed off the Texas coast...

 - Air defence radars.
Texas Tower 2
Georges Shoal, in 56-foot (17 m) deep water, 110 miles (180 km) east of Cape Cod 41°44′N 67°47′W / 41.733°N 67.783°W / 41.733; -67.783 , linked to North Truro, MA.
Texas Tower 3
Nantucket Shoals
Nantucket Shoals
Nantucket Shoals is an area of dangerously shallow water in the Atlantic Ocean that extends from Nantucket Island, Massachusetts, eastward for and southeastward for ; in places water depth can be as shallow as . Depth soundings are unpredictable due to constant change from strong currents. The...

, in 80-foot (24 m) water, 100 miles (160 km) south-east of Rhode Island 40°45′N 69°19′W / 40.75°N 69.317°W / 40.75; -69.317 , linked to Montauk AFB, Long Island, NY.
Texas Tower 4
Un-named Shoal (Unofficially: Old Shaky), in 185-foot (56 m) water, 84 miles (135 km) south-east of New York City 39°48′N 72°40′W (Destroyed, with 28 killed, during a storm on 15 January 1961), linked to Highlands, NJ mainland station.
Texas Tower ?
Cashes Ledge (Lat. 42° 53'N., Long. 68° 57'W., 36-foot depth), 100 miles east of New Hampshire, not built.
Texas Tower ?
Brown's Bank (Lat. 42° 47'N., Long. 65° 37'W., 84foot depth), 75 miles south of Nova Scotia, not built.

Mid Canada Line
A series of five stations (070, 060, 050, 415, 410) in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

 and Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

 around the lower Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

.


Pinetree Line
Pinetree Line
The Pinetree Line was a series of radar stations located across the northern United States and southern Canada at about the 50th parallel north, along with a number of other stations located on the Atlantic and Pacific coasts. Run by NORAD , over half were manned by United States Air Force...

, Pole Vault
A series of fourteen stations providing communications for Eastern seaboard radar stations of the US/Canadian Pinetree line, running from N-31 Frobisher Bay, Baffin Island to St. Johns, Labrador.


White Alice
A Military and Civil Communications network with seventy-one stations stretching up the Western seaboard from Port Hardy, Vancouver island North to Barter Island
Barter Island
Barter Island is an island located on the Arctic coast of the U.S. state of Alaska, east of Arey Island in the Beaufort Sea. It is about four miles long and about two miles wide at its widest point....

 (BAR) and east to Shemya, Alaska (SYA) in the Aleutian Islands.


DEW
Dew
[Image:Dew on a flower.jpg|right|220px|thumb|Some dew on an iris in Sequoia National Park]]Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening...

 Training
A training facility for White Alice and the DEW line tropo-scatter network, between Pecatonica, Illinois
Pecatonica, Illinois
Pecatonica, Illinois is a village in Winnebago County, Illinois, United States. It is part of the Rockford, Illinois Metropolitan Statistical Area...

 to Streator, Illinois
Streator, Illinois
Streator is a city in LaSalle and partially in Livingston counties in the U.S. state of Illinois. The city is situated on the Vermilion River approximately southwest of Chicago, Illinois in the prairie and farm land of north-central Illinois. It is the center of the geographic region known as...

.


DEW Line
Several tropo-scatter networks providing communications for the extensive air-defence radar chain in the far north of Canada and the US.


NARS
North Atlantic Radio System
The North Atlantic Radio System was a chain of five tropospheric scatter communication sites that stretched from Iceland to RAF Fylingdales, forming an extension of the Distant Early Warning Line .-Development:...

NATO Air-Defence network stretching from RAF Fylingdales
RAF Fylingdales
RAF Fylingdales is a Royal Air Force station on Snod Hill in the North York Moors, England. Its motto is "Vigilamus" . It is a radar base and part of the United States-controlled Ballistic Missile Early Warning System...

, via Mormond Hill, UK, Sornfelli
Sornfelli
.Sornfelli is a mountain plateau on the island of Streymoy in the Faroe Islands about 12 km from the capital Torshavn . It is the site of a military station at 725 m asl...

 (Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...

), Höfn, Iceland
Hofn Air Station
Hofn Air Station is a closed United States Air Force General Surveillance Radar station. It is located east of Naval Air Station Keflavik, Iceland. It was closed on 30 June 1992.-History:...

 to Keflavik DYE-5, Rockville.


ET-A, USAREUR
A US Army network from RAF Fylingdales
RAF Fylingdales
RAF Fylingdales is a Royal Air Force station on Snod Hill in the North York Moors, England. Its motto is "Vigilamus" . It is a radar base and part of the United States-controlled Ballistic Missile Early Warning System...

 to a network in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and a single station in France (Maison Fort).


486L, MEDCOM
A US Navy network covering the Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an coast of the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

 from San Pablo, Spain in the West to Adana AFB, Turkey in the East, with headquarters at Ringstead
Ringstead
Ringstead can refer to the following places in England:*Ringstead, Dorset*Ringstead, Norfolk*Ringstead, NorthamptonshireRingstead is also a surname:*Alf Ringstead, former Sheffield United footballer...

 in Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...

, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

.


Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...


Communications to British Forces Germany
British Forces Germany
British Forces Germany , is the name for British Armed Forces service personnel and civilians based in Germany. It was first established following the Second World War as the British Army of the Rhine ....

, running from Swingate in Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...

 to Lammersdorf in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

.

BARS
A Warsaw Pact tropo-scatter network that stretching from near Rostok in the DDR
DDR
DDR may refer to:In entertainment:*Dance Dance Revolution, a music video game series by Konami*DDR , a Norwegian rock band singing in German.*DDR , a Greenlandic punk band singing in Danish.In organizations:...

 (Deutsches Demokratisches Republik}, Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...

, Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

, Belarus
Belarus
Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...

sia USSR, Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

 USSR, Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 and Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

.


SEVER
Sever
-Places in Portugal:* Sever , a civil parish in the municipality of Santa Marta de Penaguião* Sever , a civil parish in Moimenta da Beira Municipality...

A Soviet right network stretching right across the USSR.


India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 - USSR
A single section from Srinigar, Kashmir
Kashmir
Kashmir is the northwestern region of the Indian subcontinent. Until the mid-19th century, the term Kashmir geographically denoted only the valley between the Great Himalayas and the Pir Panjal mountain range...

, India to Dangara, Tajikstan, USSR.


Indian Air Force
Indian Air Force
The Indian Air Force is the air arm of the Indian armed forces. Its primary responsibility is to secure Indian airspace and to conduct aerial warfare during a conflict...

An air-defence network covering the Northern borders of India with at least 32 stations.


Peace Ruby, Spellout, Peace Net
An air-defence network set up by the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 in Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

 pre-revolution. Spellout built a radar and comms network in the north of iran. Peace Ruby built another air-defence network in the south and Peace net integrated the two networks.


Bahrain
Bahrain
' , officially the Kingdom of Bahrain , is a small island state near the western shores of the Persian Gulf. It is ruled by the Al Khalifa royal family. The population in 2010 stood at 1,214,705, including 235,108 non-nationals. Formerly an emirate, Bahrain was declared a kingdom in 2002.Bahrain is...

 - UAE
A tropo-scatter system linking Al Manamah, Bahrain
Bahrain
' , officially the Kingdom of Bahrain , is a small island state near the western shores of the Persian Gulf. It is ruled by the Al Khalifa royal family. The population in 2010 stood at 1,214,705, including 235,108 non-nationals. Formerly an emirate, Bahrain was declared a kingdom in 2002.Bahrain is...

 to Dubai
Dubai
Dubai is a city and emirate in the United Arab Emirates . The emirate is located south of the Persian Gulf on the Arabian Peninsula and has the largest population with the second-largest land territory by area of all the emirates, after Abu Dhabi...

, United Arab Emirates
United Arab Emirates
The United Arab Emirates, abbreviated as the UAE, or shortened to "the Emirates", is a state situated in the southeast of the Arabian Peninsula in Western Asia on the Persian Gulf, bordering Oman, and Saudi Arabia, and sharing sea borders with Iraq, Kuwait, Bahrain, Qatar, and Iran.The UAE is a...

.


RAFO
A tropo-scatter communications system providing military comms to the former SOAF - Sultan of Oman's Air Force, (now RAFO - Royal Air Force of Oman
Royal Air Force of Oman
The Royal Air Force of Oman is the air arm of the Sultan of Oman's Armed Forces-History:...

), across the Sultanate of Oman.


RSAF
RSAF
The acronym RSAF may refer to:*Republic of Singapore Air Force*Royal Saudi Air Force*Royal Small Arms Factory...

A Royal Saudi Air Force
Royal Saudi Air Force
The Royal Saudi Air Force , is the aviation branch of the Saudi Arabian armed forces. The RSAF has developed from a largely defensive military force into one with an advanced offensive capability...

 tropo-scatter network linking major airbases and population centres in Saudi Arabia
Saudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...

.


Yemen
Yemen
The Republic of Yemen , commonly known as Yemen , is a country located in the Middle East, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, and Oman to the east....

A single system linking Sana'a
Sana'a
-Districts:*Al Wahdah District*As Sabain District*Assafi'yah District*At Tahrir District*Ath'thaorah District*Az'zal District*Bani Al Harith District*Ma'ain District*Old City District*Shu'aub District-Old City:...

 with Sa'dah
Sa'dah
Sa`dah is the capital city of Saada Governorate in north-western Yemen. It is located at , at an elevation of about 1,800 meters. Known in antiquity as Karna, its population in 2004 was estimated at 51,870.- External links :*...

.


BACK PORCH and IWCS
Two networks run by the nited States linking military bases in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

 and South Vietnam
South Vietnam
South Vietnam was a state which governed southern Vietnam until 1975. It received international recognition in 1950 as the "State of Vietnam" and later as the "Republic of Vietnam" . Its capital was Saigon...

.


Phil - Tai - Oki
A system linking the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

 with Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

.

Japanese Troposcatter Networks
Two networks linking Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese islands from North to South.

Tactical Troposcatter Communication systems


As well as the permanent networks detailed above, there have been many tactical transportable systems produced by several countries:-
Soviet / Russian Troposcatter Systems
MNIRTI R-423-1 Brig-1/R-423-2A Brig-2A/R-423-1KF
MNIRTI R-444 Eshelon / R-444-7,5 Eshelon D
MNIRTI R-420 Atlet-D
NIRTI R-417 Baget/R-417S Baget S
PP Radiosvyaz R-412] A/B/F/S TORF
MNIRTI R-410/R-410-5,5/R-410-7,5 Atlet / Albatros
MNIRTI R-408/R-408M Baklan


Peoples Republic of China (PRoC), Peoples Liberation Army (PLA) Troposcatter Systems
CETC TS-504[ Troposcatter Communication System
CETC TS-510/GS-510 Troposcatter Communication System


Western Troposcatter Systems
AN/TRC-97 Troposcatter Communication System
AN/TRC-170 Tropospheric Scatter Microwave Radio Terminal
AN/GRC-201 Troposcatter Communication System



The U.S. Army and Air Force use tactical tropospheric scatter systems developed by Raytheon
Raytheon
Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...

 for long haul communications. The systems come in two configurations, the original "heavy tropo", and a newer "light tropo" configuration exist. The systems provide four multiplexed
Multiplexing
The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...

 group channels and trunk encryption, and 16 or 32 local analog phone extensions. The U.S. Marine Corps also uses the same device, albeit an older version.

See also

  • Radio propagation
    Radio propagation
    Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...

  • Non-line-of-sight propagation
    Non-line-of-sight propagation
    Non-line-of-sight or near-line-of-sight is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone....

  • Microwave
    Microwave
    Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

  • ACE High
    ACE High
    ACE High was a NATO communications system which dates back to 1956. The system was decommissioned in the late 1980s, and its frequencies reallocated for commercial radiotelephone service. The system was designed to be an L-band troposcatter radio system, which was meant to provide long-range...

     - Cold war era NATO European troposcatter network
  • White Alice Communications System
    White Alice Communications System
    The White Alice Communications System was a United States Air Force telecommunication link system constructed in Alaska during the cold war. It featured tropospheric scatter links and line-of-sight microwave radio links...

     - Cold war era Alaskan tropospheric communications link
  • List of White Alice Communications System sites
  • TV-FM DX
    TV-FM DX
    TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning "long distance."...

  • List of DEW Line Sites
  • Distant Early Warning Line
    Distant Early Warning Line
    The Distant Early Warning Line, also known as the DEW Line or Early Warning Line, was a system of radar stations in the far 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...


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