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Tropospheric propagation describes
electromagnetic propagation Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected ...
in relation to the
troposphere The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the ...
. The service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a "deep fringe" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the
troposphere The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the ...
. Tropospheric propagated signals travel in the part of the
atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...
adjacent to the surface and extending to some 25,000 feet (8 km). Such signals are thus directly affected by
weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...
conditions extending over some hundreds of miles. During very settled, warm
anticyclonic A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interpl ...
weather (i.e., high
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...
), usually weak signals from distant transmitters improve in strength. Another symptom during such conditions may be
interference Interference is the act of interfering, invading, or poaching. Interference may also refer to: Communications * Interference (communication), anything which alters, modifies, or disrupts a message * Adjacent-channel interference, caused by extra ...
to the local transmitter resulting in
co-channel interference Co-channel interference or CCI is crosstalk from two different radio transmitters using the same channel. Co-channel interference can be caused by many factors from weather conditions to administrative and design issues. Co-channel interferen ...
, usually horizontal lines or an extra floating picture with analog broadcasts and break-up with digital broadcasts. A settled high-pressure system gives the characteristic conditions for enhanced tropospheric propagation, in particular favouring signals which travel along the prevailing isobar pattern (rather than across it). Such weather conditions can occur at any time, but generally the summer and autumn months are the best periods. In certain favourable locations, enhanced tropospheric propagation may enable reception of
ultra high frequency Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
(UHF) TV signals up to or more. The observable characteristics of such high-pressure systems are usually clear, cloudless days with little or no wind. At sunset the upper air cools, as does the surface temperature, but at different rates. This produces a boundary or
temperature gradient A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature spatial gradient is a vector quantity with Dimensional analysis, ...
, which allows an inversion level to form – a similar effect occurs at sunrise. The inversion is capable of allowing very high frequency (VHF) and UHF signal propagation well beyond the normal
radio horizon Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves can only travel in a direct visual path from the source to the receiver without obstacles. Electromagnetic transmission incl ...
distance. The inversion effectively reduces sky wave
radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...
from a transmitter – normally VHF and UHF signals travel on into space when they reach the horizon, the
refractive index In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...
of the ionosphere preventing signal return. With temperature inversion, however, the signal is to a large extent
refracted In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenome ...
over the horizon rather than continuing along a direct path into outer space.
Fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus and is heavily influenc ...
also produces good tropospheric results, again due to inversion effects. Fog occurs during high-pressure weather, and if such conditions result in a large belt of fog with clear sky above, there will be heating of the upper fog level and thus an inversion. This situation often arises towards night fall, continues overnight and clears with the sunrise over a period of around 4 – 5 hours.


Tropospheric ducting

Tropospheric ducting is a type of radio propagation that tends to happen during periods of stable, anticyclonic weather. In this propagation method, when the signal encounters a rise in temperature in the atmosphere instead of the normal decrease (known as a temperature inversion), the higher
refractive index In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...
of the atmosphere there will cause the signal to be bent. Tropospheric ducting affects all frequencies, and signals enhanced this way tend to travel up to (though some people have received "tropo" beyond 1,000 miles / 1,600 km), while with tropospheric-bending, stable signals with good signal strength from 500+ miles (800+ km) away are not uncommon when the refractive index of the atmosphere is fairly high. Tropospheric ducting of radio and television signals is relatively common during the summer and autumn months, and is the result of change in the refractive index of the atmosphere at the boundary between air masses of different
temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
s and humidities. Using an
analogy Analogy is a comparison or correspondence between two things (or two groups of things) because of a third element that they are considered to share. In logic, it is an inference or an argument from one particular to another particular, as oppose ...
, it can be said that the denser air at ground level slows the wave front a little more than does the rare upper air, imparting a downward curve to the wave travel. Ducting can occur on a very large scale when a large mass of cold air is overrun by warm air. This is termed a
temperature inversion In meteorology, an inversion (or temperature inversion) is a phenomenon in which a layer of warmer air overlies cooler air. Normally, air temperature gradually decreases as altitude increases, but this relationship is reversed in an inver ...
, and the boundary between the two air masses may extend for or more along a stationary
weather front A weather front is a boundary separating air masses for which several characteristics differ, such as air density, wind, temperature, and humidity. Disturbed and unstable weather due to these differences often arises along the boundary. For ins ...
. Temperature inversions occur most frequently along coastal areas bordering large bodies of water. This is the result of natural onshore movement of cool, humid air shortly after sunset when the ground air cools more quickly than the upper air layers. The same action may take place in the morning when the rising sun warms the upper layers. Even though tropospheric ducting has been occasionally observed down to 40 MHz, the signal levels are usually very weak. Higher frequencies above 90 MHz are generally more favourably propagated. High
mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...
ous areas and undulating terrain between the transmitter and receiver can form an effective barrier to tropospheric signals. Ideally, a relatively flat land path between the transmitter and receiver is ideal for tropospheric ducting. Sea paths also tend to produce superior results. In certain parts of the world, notably the
Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...
and the
Persian Gulf The Persian Gulf, sometimes called the Arabian Gulf, is a Mediterranean seas, mediterranean sea in West Asia. The body of water is an extension of the Arabian Sea and the larger Indian Ocean located between Iran and the Arabian Peninsula.Un ...
, tropospheric ducting conditions can become established for many months of the year to the extent that viewers regularly receive quality reception of signals over distances of . Such conditions are normally optimum during very hot settled summer weather. Tropospheric ducting over water, particularly between
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
and
Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
,
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
and
Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
, Australia and
New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
, Australia and
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
, Strait of Florida, and
Bahrain Bahrain, officially the Kingdom of Bahrain, is an island country in West Asia. Situated on the Persian Gulf, it comprises a small archipelago of 50 natural islands and an additional 33 artificial islands, centered on Bahrain Island, which mak ...
and
Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
, has produced VHF/UHF reception ranging from 1000 to 3,000 miles (1,600 – 4,800 km). A US listening post was built in Ethiopia to exploit a common ducting of signals from southern Russia. Tropospheric signals exhibit a slow cycle of fading and will occasionally produce signals sufficiently strong for noise-free
stereo Stereophonic sound, commonly shortened to stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configurat ...
, reception of
Radio Data System Radio Data System (RDS) is a communications protocol standard for embedding small amounts of digital information in conventional FM broadcasting, FM radio broadcasts. RDS standardizes several types of information transmitted, including time, sta ...
(RDS) data, and solid locks of
HD Radio HD Radio (HDR) is a trademark for in-band on-channel (IBOC) digital radio broadcast technology. HD radio generally simulcast, simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD R ...
streams on FM, noise-free, color TV pictures, or stable DTV reception, as well stable DAB Radio reception. With
DVB-T DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Fe ...
it can also enable a wide SFN, so long as the two transmitters are within a guard interval and are almost equidistant from the receiver as well as synchronised. However, if they are not synchronised and are not equidistant they will interfere with each other. Virtually all long-distance reception of
digital television Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...
occurs by tropospheric ducting (due to most, but not all, TV stations broadcasting in the
UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
band).


Notable and record distance tropospheric DX receptions

"DXing is the art and science of listening to distant stations." The ARRL, association for amateur radio maintains the list of North American distance records, which includes tropo results. * On October 18, 1975, Rijn Muntjewerff, the
Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
, received UHF channel E34
Pajala Pajala () is a locality and the seat of Pajala Municipality in Norrbotten County, Sweden, with 1,958 inhabitants in 2010. It is located in Swedish Lapland. Pajala is in part of the Meänmaa (Torne valley) region and was in past times unilingua ...
,
Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
, at a distance of . * On June 13, 1989, Shel Remington, Keaau,
Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
, received several 88–108 MHz FM signals from
Tijuana Tijuana is the most populous city of the Mexican state of Baja California, located on the northwestern Pacific Coast of Mexico. Tijuana is the municipal seat of the Tijuana Municipality, the hub of the Tijuana metropolitan area and the most popu ...
,
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
, at a distance of . * Throughout the 1990s, Fernando Garcia, located at what could be considered an ideal tropospheric DX location near
Monterrey Monterrey (, , abbreviated as MtY) is the capital and largest city of the northeastern Mexican state of Nuevo León. It is the ninth-largest city and the second largest metropolitan area, after Greater Mexico City. Located at the foothills of th ...
,
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
, received numerous 1,000+ mile (1,600+ km) stations via tropospheric propagation, both over the
Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
and past land. Among his receptions are WGNT-27 from
Portsmouth, Virginia Portsmouth is an Independent city (United States), independent city in southeastern Virginia, United States. It lies across the Elizabeth River (Virginia), Elizabeth River from Norfolk, Virginia, Norfolk. As of the 2020 United States census, 2020 ...
, at a distance of and low-power (
LPTV Low-power broadcasting is broadcasting by a broadcast station at a low transmitter power output to a smaller service area than "full power" stations within the same region. It is often distinguished from "micropower broadcasting" (more commonl ...
) station W38BB from
Raleigh, North Carolina Raleigh ( ) is the List of capitals in the United States, capital city of the U.S. state of North Carolina. It is the List of municipalities in North Carolina, second-most populous city in the state (after Charlotte, North Carolina, Charlotte) ...
, at a distance of * On May 11, 2003, Jeff Kruszka, living in south
Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...
, received a few UHF DTV signals from 800+ miles. The longest of these was WNCN-DT, channel 55,
Goldsboro, North Carolina Goldsboro, originally Goldsborough, is a city in and the county seat of Wayne County, North Carolina, United States. The population was 33,657 at the 2020 census. It is the principal city of and is included in the Goldsboro, North Carolina Me ...
, at a distance of (at the time, the record for UHF DTV). * On December 9, 2004, Polish DXer Maciej Ługowski received the British TV stations Channel 5 (on UHF ch.37 from the Croydon transmitter) and
BBC2 BBC Two is a British free-to-air public broadcast television channel owned and operated by the BBC. It is the corporation's second flagship channel, and it covers a wide range of subject matter, incorporating genres such as comedy, drama and ...
(UHF ch.46 from Bluebell Hill transmitter) near Warsaw, Poland at and , respectively. * On October 15, 2006, a German DXer known on YouTube as EifelDX received the Norge Mux on channel E58, transmitter Oslo, with a distance of . * On the late evening of June 19, 2007 and into the early morning hours of June 20, 2007, three DXers in eastern
Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...
, Jeff Lehmann, Keith McGinnis, and Roy Barstow, received FM signals from southern Florida via tropo. All three logged
WEAT WEAT (107.9 FM) is a commercial radio station in West Palm Beach, Florida. it airs a classic hits radio format, switching to Christmas music for much of November and December. It is owned by Hubbard Broadcasting, through licensee WPB FCC Lice ...
104.3
West Palm Beach West Palm Beach is a city in and the county seat of Palm Beach County, Florida, United States. It is located immediately to the west of the adjacent Palm Beach, Florida, Palm Beach, which is situated on a barrier island across the Lake Worth Lag ...
,
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
, and
WRMF WRMF (97.9 FM broadcasting, FM) is a commercial broadcasting, commercial radio station in Palm Beach, Florida. It serves the northern sections of the Miami metropolitan area, including West Palm Beach and Fort Lauderdale, Florida, Fort Lauderda ...
97.9 Palm Beach,
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
, at distances of around , and Barstow logged WHDR 93.1
Miami Miami is a East Coast of the United States, coastal city in the U.S. state of Florida and the county seat of Miami-Dade County, Florida, Miami-Dade County in South Florida. It is the core of the Miami metropolitan area, which, with a populat ...
,
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
, at a distance of . * On December 17, 2007, Polish DXer Maciej Ługowski received
BBC Radio Scotland BBC Radio Scotland is a Scottish national radio network owned and operated by BBC Scotland, a division of the BBC. It broadcasts a wide variety of programmes. It replaced the Scottish BBC Radio 4 opt-out service of the same name from 23 N ...
on 93,7 MHz from Keelylang Hill (
Orkney Islands Orkney (), also known as the Orkney Islands, is an archipelago off the north coast of mainland Scotland. The plural name the Orkneys is also sometimes used, but locals now consider it outdated. Part of the Northern Isles along with Shetland ...
) transmitter near Warsaw, Poland at distance. BBC Scotland reception continued for next two days. *
On November 3, 2008, Swedish Radio Amateur Kjell Jarl SM7GVF contacted Russian Radio Amateur RA6HHT
at a distance of on 144Mhz. *
On April 23, 2009, a
San Antonio San Antonio ( ; Spanish for " Saint Anthony") is a city in the U.S. state of Texas and the most populous city in Greater San Antonio. San Antonio is the third-largest metropolitan area in Texas and the 24th-largest metropolitan area in the ...
-area DXer received
WFTS-TV WFTS-TV (channel 28), branded as ABC Action News, is a television station licensed to Tampa, Florida, United States, serving the Tampa Bay area as an affiliate of ABC. It is owned by the E.W. Scripps Company alongside Bradenton-licensed Ion Te ...
28's digital signal from
Tampa, Florida Tampa ( ) is a city on the Gulf Coast of the United States, Gulf Coast of the U.S. state of Florida. Tampa's borders include the north shore of Tampa Bay and the east shore of Old Tampa Bay. Tampa is the largest city in the Tampa Bay area and t ...
, at a distance of .
* On the late evening of August 24 into the afternoon of August 25, 2009, a DX'er in Burnt River, Ontario,
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
, received several FM radio stations via tropo from
Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...
,
Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
,
Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...
,
Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...
,
Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...
,
Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...
,
Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
,
Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...
,
Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
, and
Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...
.'' (archived
''
* On September 28, 2016, European tropospheric FM DX record was newly set by Jürgen Bartels in Süllwarden, Northern Germany who received Spanish station RNE5TN on 93.7 MHz from Santiago de Compostela/Monte Pedroso transmitter at distance. * On September 27 and 28, 2017, various DXers in northeastern Europe observed extreme ducting in VHF broadcast band. Top distance was achieved by Łukasz K. in Tomaszów Mazowiecki, Poland, who reported signals from Kolari transmitter, northern Finland at . * On October 10, 2018, Ukrainian DXer Vladimir Doroshenko (MrVlaDor) received a signal from Danish transmitter Holstebro/Mejrup in Dnipro at a distance of . It sets the new tropo FM DX record for Europe. At the same time, FM DXers in Poland received FM radiostations from Moscow for the first time via troposphere at distances – . * On July 16, 2023, an Australian DXer known on YouTube as VK2KRR received UHF television signals from Port Pirie at The Rock Hill in NSW, at a distance of . This ultimately sets a new tropo UHF DTV DX record for Australia.


See also

* MW DX *
Skywave In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvatur ...
*
Radio propagation Radio propagation is the behavior of radio waves as they travel, or are wave propagation, propagated, from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio w ...
*
Tropospheric scatter Tropospheric scatter, also known as troposcatter, is a method of communicating with microwave radio signals over considerable distances – often up to and further depending on frequency of operation, equipment type, terrain, and climate fact ...
* Velocity of propagation * Thermal fade *
Clear-channel station A clear-channel station is a North American AM radio station that has the highest level of protection from interference from other stations, particularly from nighttime skywave signals. This classification exists to ensure the viability of cross ...
*
Federal Standard 1037C Federal Standard 1037C, titled Telecommunications: Glossary of Telecommunication Terms, is a United States Federal Standard issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, ...
*
Looming and similar refraction phenomena While mirages are the best known atmospheric refraction phenomena, looming and similar refraction phenomena do not produce mirages. Mirages show an extra image or images of the miraged object, while looming, towering, stooping, and sinking do not. ...


References


External links

* * * Tropospheric Ducting YouTube Channel of FMDXUA �

* *''oldtvguides.com'' {{DEFAULTSORT:Tropospheric Propagation Radio frequency propagation th:ทีวีดีเอกซ์