Radio masts and towers
Radio masts and towers are tall structures designed to support antennas for telecommunications and broadcasting, including television. There are two main types: self-supporting structures, they are among the tallest human-made structures. Masts are named after the broadcasting organizations that built them or use them. In the case of a mast radiator or radiating tower, the whole mast or tower is itself the transmitting antenna; the terms "mast" and "tower" are used interchangeably. However, in structural engineering terms, a tower is a self-supporting or cantilevered structure, while a mast is held up by stays or guys. Broadcast engineers in the UK use the same terminology. A mast is a ground-based or rooftop structure that supports antennas at a height where they can satisfactorily send or receive radio waves. Typical masts are of tubular steel construction. Masts themselves play no part in the transmission of mobile telecommunications. Masts tend to be cheaper to build but require an extended area surrounding them to accommodate the guy wires.
Towers are more used in cities where land is in short supply. There are a few borderline designs that are free-standing and guyed, called additionally guyed towers. For example: The Gerbrandy tower consists of a self-supporting tower with a guyed mast on top; the few remaining Blaw-Knox towers do the opposite: they have a guyed lower section surmounted by a freestanding part. Zendstation Smilde, a tall tower with a guyed mast on top with guys which go to ground. Torre de Collserola, a guyed tower with a guyed mast on top where the tower portion is not free-standing. Experimental radio broadcasting began in 1905, commercial radio broke through in the 1920s; until August 8, 1991, the Warsaw radio mast was the world's tallest supported structure on land. There are over 50 radio structures in the United States that are taller; the steel lattice is the most widespread form of construction. It provides great strength, low weight and wind resistance, economy in the use of materials. Lattices of triangular cross-section are most common, square lattices are widely used.
Guyed masts are used. When built as a tower, the structure may be taper over part or all of its height; when constructed of several sections which taper exponentially with height, in the manner of the Eiffel Tower, the tower is said to be an Eiffelized one. The Crystal Palace tower in London is an example. Guyed masts are sometimes constructed out of steel tubes; this construction type has the advantage that cables and other components can be protected from weather inside the tube and the structure may look cleaner. These masts are used for FM-/TV-broadcasting, but sometimes as mast radiator; the big mast of Mühlacker transmitting station is a good example of this. A disadvantage of this mast type is that it is much more affected by winds than masts with open bodies. Several tubular guyed masts have collapsed. In the UK, the Emley Moor and Waltham TV stations masts collapsed in the 1960s. In Germany the Bielstein transmitter collapsed in 1985. Tubular masts were not built in all countries. In Germany, France, UK, Czech Republic, Slovakia and the Soviet Union, many tubular guyed masts were built, while there are nearly none in Poland or North America.
In several cities in Russia and Ukraine several tubular guyed masts with crossbars running from the mast structure to the guys were built in the 1960s. All these masts, which are designed as 30107 KM, are used for FM and TV transmission and, except for the mast in Vinnytsia, are between 150–200-metre tall; the crossbars of these masts are equipped with a gangway that holds smaller antennas, though their main purpose is oscillation damping. Reinforced concrete towers are expensive to build but provide a high degree of mechanical rigidity in strong winds; this can be important when antennas with narrow beamwidths are used, such as those used for microwave point-to-point links, when the structure is to be occupied by people. In the 1950s, AT&T built numerous concrete towers, more resembling silos than towers, for its first transcontinental microwave route. In Germany and the Netherlands most towers constructed for point-to-point microwave links are built of reinforced concrete, while in the UK most are lattice towers.
Concrete towers can form prestigious landmarks, such as the CN Tower in Canada. In addition to accommodating technical staff, these buildings may have public areas such as observation decks or restaurants; the Stuttgart TV tower was the first tower in the world to be built in reinforced concrete. It was designed in 1956 by the local civil engineer Fritz Leonhardt. Fiberglass poles are used for low-power non-directional beacons or medium-wave broadcast transmitters. Carbon fibre monopoles and towers have traditionally been too expensive but recent developments in the way the carbon fibre tow is spun have resulted in solutions that offer strengths similar or exceeding steel for a fraction of the weight which has allowed monopoles and towers to be built in locations that were too expensive or difficult to access with the heavy lifting equipment, needed for a steel structure. Wood has been superseded in use by metal and composites for tower construction. Many wood towers were built in the UK during World War II because of a shortage of steel.
In Germany before World War II wooden towers were used at nearly all medium-wave transmission sites which hav
A summit is a point on a surface, higher in elevation than all points adjacent to it. The topographic terms acme, apex and zenith are synonymous; the term top is used only for a mountain peak, located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are considered subsummits of the higher peak, are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may refer to the highest point along a line, trail, or route; the highest summit in the world is Everest with height of 8844.43 m above sea level. The first official ascent was made by Sir Edmund Hillary, they reached the mountain`s peak in 1953. Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective; the UIAA definition of a peak is.
Otherwise, it's a subpeak. In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit. A summit climbing differs from the common mountaineering. Summit expedition requires: 1+ year of training, a good physical shape, a special gear. Although a huge part of climber’s stuff can be left and taken at the base camps or given to porters, there is a long list of personal equipment. In addition to common mountaineers’ gear, Summit climbers need to take Diamox and bottles of oxygen. There are special requirements for crampons, ice axe, rappel device, etc. Geoid Hill – Landform that extends above the surrounding terrain Nadir Summit accordance Peak finder Summit Climbing Gear List
A radome is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material that minimally attenuates the electromagnetic signal transmitted or received by the antenna transparent to radio waves. Radomes conceal antenna electronic equipment from view, they protect nearby personnel from being accidentally struck by rotating antennas. Radomes can be constructed in several shapes — spherical, planar, etc. — depending on the particular application, using various construction materials such as fiberglass, PTFE-coated fabric, others. When found on fixed-wing aircraft with forward-looking radar, as are used for object or weather detection, the nose cones additionally serve as radomes. On aircraft used for airborne early warning and control, a rotating radome called a "rotodome", is mounted on the top of the fuselage for 360-degree coverage; some newer AEW&C configurations instead use three antenna modules inside a radome mounted on top of the fuselage, for 360-degree coverage, such as the Chinese KJ-2000 and Indian DRDO AEW&Cs.
On rotary-wing and fixed-wing aircraft using microwave satellite for beyond-line-of-sight communication, radomes appear as blisters on the fuselage. In addition to protection, radomes streamline the antenna system, thus reducing drag. A radome is used to prevent ice and freezing rain from accumulating on antennas. In the case of a spinning radar parabolic antenna, the radome protects the antenna from debris and rotational irregularities due to wind, its shape is identified by its hardshell, which has strong properties against being damaged. For stationary antennas, excessive amounts of ice can de-tune the antenna to the point where its impedance at the input frequency rises drastically, causing the voltage standing wave ratio to rise as well; this reflected. A foldback circuit can act to prevent this. A radome avoids that by covering the antenna's exposed parts with a sturdy, weatherproof material fiberglass, keeping debris or ice away from the antenna, thus preventing any serious issues. One of the main driving forces behind the development of fiberglass as a structural material was the need during World War II for radomes.
When considering structural load, the use of a radome reduces wind load in both normal and iced conditions. Many tower sites require or prefer the use of radomes for wind loading benefits and for protection from falling ice or debris. Where radomes might be considered unsightly if near the ground, electric antenna heaters could be used instead. Running on direct current, the heaters do not interfere physically or electrically with the alternating current of the radio transmission. For radar dishes, a single, ball-shaped dome protects the rotational mechanism and the sensitive electronics, is heated in colder climates to prevent icing; the RAF Menwith Hill electronic surveillance base, which includes over 30 radomes, is believed to intercept satellite communications. At Menwith Hill, the radome enclosures prevent observers from seeing the direction of the antennas, therefore which satellites are being targeted. Radomes prevent observation of antennas used in ECHELON facilities; the United States Air Force Aerospace Defense Command operated and maintained dozens of air defense radar stations in the contiguous United States and Alaska during the Cold War.
Most of the radars used at these ground stations were protected by inflatable radomes. The radomes were at least 15 m in diameter and the radomes were attached to standardized radar tower buildings that housed the radar transmitter and antenna; some of these radomes were large. The CW-620 was a space frame rigid radome with a maximum diameter of 46 m, a height of 26 m; this radome consisted of 590 panels, was designed for winds up to 240 km/h. The total radome weight was 92,700 kg with a surface area of 3,680 m2; the CW-620 radome was designed and constructed by Sperry-Rand Corporation for the Columbus Division of North American Aviation. This radome was used for the FPS-35 search radar at Baker Air Force Station, Oregon; when Baker AFS was closed the radome was moved to provide a high-school gymnasium in Idaho. Pictures and documents are available online at radomes.org/museum for Baker AFS/821st Radar Squadron. For maritime satellite communications service, radomes are used to protect dish antennas which are continually tracking fixed satellites while the ship experiences pitch and yaw movements.
Large cruise ships and oil tankers may have radomes over 3 m in diameter covering antennas for broadband transmissions for television, voice and the Internet, while recent developments allow similar services from smaller installations such as the 85 cm motorised dish used in the SES Broadband for Maritime system. Small private yachts may use radomes as small as 26 cm in diameter for voice and low-speed data. An active electronically scanned array radar has no moving antenna and so a radome is not necessary. An example of this is the "pyramid" which replaced the "tourist attraction" golfball-style radome installations at RAF Fylingdales. Photograph of Mount Hebo while active overlooking Pacific Ocean
U.S. National Geodetic Survey
"United States Coast Survey" and "United States Coast and Geodetic Survey" redirect here. They are former scientific agencies of the United States government which should not be confused with the United States Coast Guard, a seagoing U. S. government law enforcement and safety agency, the modern Coast Survey, a U. S. government agency that makes nautical charts, or the United States Geological Survey, a U. S. government agency that studies earth science and makes topographical maps. The National Geodetic Survey the United States Survey of the Coast, United States Coast Survey, United States Coast and Geodetic Survey, is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication. Since its foundation in its present form in 1970, it has been part of the National Oceanic and Atmospheric Administration, of the United States Department of Commerce; the National Geodetic Survey's history and heritage are intertwined with those of other NOAA offices.
As the U. S. Coast Survey and U. S. Coast and Geodetic Survey, the agency operated a fleet of survey ships, from 1917 the Coast and Geodetic Survey was one of the uniformed services of the United States with its own corps of commissioned officers. Upon the creation of the Environmental Science Services Administration in 1965, the commissioned corps was separated from the Survey to become the Environmental Science Services Administration Corps. Upon the creation of NOAA in 1970, the ESSA Corps became the National Oceanic and Atmospheric Administration Commissioned Officer Corps. Thus, the National Geodetic Survey's ancestor organizations are the ancestors of today's NOAA Corps and Office of Coast Survey and are among the ancestors of today's NOAA fleet. In addition, today's National Institute of Standards and Technology, although long since separated from the Survey, got its start as the Survey's Office of Weights and Measures; the National Geodetic Survey is an office of NOAA's National Ocean Service.
Its core function is to maintain the National Spatial Reference System, "a consistent coordinate system that defines latitude, height, scale and orientation throughout the United States." NGS is responsible for defining the NSRS and its relationship with the International Terrestrial Reference Frame. The NSRS enables precise and accessible knowledge of where things are in the United States and its territories; the NSRS may be divided into its geometric and physical components. The official geodetic datum of the United States, NAD83 defines the geometric relationship between points within the United States in three-dimensional space; the datum may be accessed via NGS's network of survey marks or through the Continuously Operating Reference Station network of GPS reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF; the physical components of the NSRS are reflected in its height system, defined by the vertical datum NAVD88. This datum is a network of orthometric heights obtained through spirit leveling.
Because of the close relationship between height and Earth's gravity field, NGS collects and curates terrestrial gravity measurements and develops regional models of the geoid and its slope, the deflection of the vertical. NGS is responsible for ensuring the accuracy of the NSRS over time as the North American plate rotates and deforms over time due to crustal strain, post-glacial rebound, elastic deformation of the crust, other geophysical phenomena. NGS will release new datums in 2022; the North American Terrestrial Reference Frame of 2022 will supersede NAD83 in defining the geometric relationship between the North American plate and the ITRF. United States territories on the Pacific and Mariana plates will have their own respective geodetic datums; the North American-Pacific Geopotential Datum of 2022 will separately define the height system of the United States and its territories, replacing NAVD88. It will use a geoid model accurate to 1 centimeter to relate orthometric height to ellipsoidal height measured by GPS, eliminating the need for future leveling projects.
This geoid model will be based on airborne and terrestrial gravity measurements collected by NGS's GRAV-D program as well as satellite-based gravity models derived from observations collected by GRACE, GOCE, satellite altimetry missions. NGS provides a number of other public services, it maps changing shorelines in the United States and provides aerial imagery of regions affected by natural disasters, enabling rapid damage assessment by emergency managers and members of the public. The Online Positioning and User Service processes user-input GPS data and outputs position solutions within the NSRS; the agency offers other tools for conversion between datums. The original predecessor agency of the National Geodetic Survey was the United States Survey of the Coast, created within the United States Department of the Treasury by an Act of Congress on February 10, 1807, to conduct a "Survey of the Coast." The Survey of the Coast, the United States government's first scientific agency, represented the interest of the administration of President Thomas Jefferson in science and the stimulation of international trade by using scientific surveying methods to chart t
A mountain range or hill range is a series of mountains or hills ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form and alignment that have arisen from the same cause an orogeny. Mountain ranges are formed by a variety of geological processes, but most of the significant ones on Earth are the result of plate tectonics. Mountain ranges are found on many planetary mass objects in the Solar System and are a feature of most terrestrial planets. Mountain ranges are segmented by highlands or mountain passes and valleys. Individual mountains within the same mountain range do not have the same geologic structure or petrology, they may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, fold mountains, volcanic landforms resulting in a variety of rock types. Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or the Alpide Belt.
The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera along the Pacific Coast, the Aleutian Range, on through Kamchatka, Taiwan, the Philippines, Papua New Guinea, to New Zealand. The Andes is 7,000 kilometres long and is considered the world's longest mountain system; the Alpide belt includes Indonesia and Southeast Asia, through the Himalaya, Caucasus Mountains, Balkan Mountains fold mountain range, the Alps, ends in the Spanish mountains and the Atlas Mountains. The belt includes other European and Asian mountain ranges; the Himalayas contain the highest mountains in the world, including Mount Everest, 8,848 metres high and traverses the border between China and Nepal. Mountain ranges outside these two systems include the Arctic Cordillera, the Urals, the Appalachians, the Scandinavian Mountains, the Great Dividing Range, the Altai Mountains and the Hijaz Mountains. If the definition of a mountain range is stretched to include underwater mountains the Ocean Ridges form the longest continuous mountain system on Earth, with a length of 65,000 kilometres.
The mountain systems of the earth are characterized by a tree structure, where mountain ranges can contain sub-ranges. The sub-range relationship is expressed as a parent-child relationship. For example, the White Mountains of New Hampshire and the Blue Ridge Mountains are sub-ranges of the Appalachian Mountains. Equivalently, the Appalachians are the parent of the White Mountains and Blue Ridge Mountains, the White Mountains and the Blue Ridge Mountains are children of the Appalachians; the parent-child expression extends to the sub-ranges themselves: the Sandwich Range and the Presidential Range are children of the White Mountains, while the Presidential Range is parent to the Northern Presidential Range and Southern Presidential Range. The position of mountains influences climate, such as snow; when air masses move up and over mountains, the air cools producing orographic precipitation. As the air descends on the leeward side, it warms again and is drier, having been stripped of much of its moisture.
A rain shadow will affect the leeward side of a range. Mountain ranges are subjected to erosional forces which work to tear them down; the basins adjacent to an eroding mountain range are filled with sediments which are buried and turned into sedimentary rock. Erosion is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains; the early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet of Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to the east; this mass of rock was removed as the range was undergoing uplift. The removal of such a mass from the core of the range most caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment.
Computer simulation has shown that as mountain belts change from tectonically active to inactive, the rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System are isolated and formed by processes such as impacts, though there are examples of mountain ranges somewhat similar to those on Earth. Saturn's moon Titan and Pluto, in particular exhibit large mountain ranges in chains composed of ices rather than rock. Examples include the Mithrim Montes and Doom Mons on Titan, Tenzing Montes and Hillary Montes on Pluto; some terrestrial planets other than Earth exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars, Jupiter's moon Io has mountain ranges formed from tectonic processes including Boösaule Montes, Dorian Montes, Hi'iaka Montes and Euboea Montes. Peakbagger Ranges Home Page Bivouac.com
The Cumberland Mountains are a mountain range in the southeastern section of the Appalachian Mountains. They are located in western Virginia, eastern edges of Kentucky, eastern middle Tennessee, including the Crab Orchard Mountains, their highest peak, with an elevation of 4,223 feet above mean sea level, is High Knob, located near Norton, Virginia. According to the USGS, the Cumberland Mountain range is 131 miles long and 20 miles wide, bounded by the Russell Fork on the northeast, the Pound River and Powell River on the southeast, Cove Creek on the southwest, Tackett Creek, the Cumberland River, Poor Fork Cumberland River, Elkhorn Creek on the northwest; the crest of the range forms the Kentucky and Virginia boundary from the Tennessee border to the Russell Fork River. Variant names of the Cumberland Mountains include Cumberland Mountain, Cumberland Range, Ouasioto Mountains, Ouasiota Mountains, Laurel Mountain, Pine Mountain, they are named for Duke of Cumberland. The Cumberland Mountains range includes Pine Mountain, Cumberland Mountain, Log Mountain, Little Black Mountain and Black Mountain, as well as others.
Oak Ridge National Laboratory is involved with the conservation of the mixed mesophytic forests within the northern Cumberland Plateau in Tennessee. The conservation organizations include The Nature Conservancy, the Doris Duke Charitable Foundation, the Natural Resources Defense Council with focus on the Cumberland Plateau; the Cumberland Mountains are a physiographic section of the larger Appalachian Plateau province, which in turn is part of the larger Appalachian physiographic division. Pine Mountain is a long, narrow ridge starting in northern Tennessee and extending northeastward into southeastern Kentucky and southwestern Virginia, its southwestern terminus is near Pioneer, it extends 122 miles to the northeast to near the Breaks Interstate Park in Kentucky and Virginia. Pine Mountain is at the headward ramp of the Pine Mountain Thrust Fault; the hard Lee-type sandstones of the Early Pennsylvanian form the ridge line. The sandstone strata crop out here because northwestward movement along the thrust fault caused these sandstones to be pushed up the ramp and over younger strata.
Because the sandstones are resistant to erosion, they form a prominent ridge along this ramp. The southwestern terminus of Pine Mountain is marked by the northwest-trending Jacksboro Fault, a lateral ramp fault; the northwestern slope of Pine Mountain is cliff-lined whereas the southeastern slope is gentle, this is the dip slope, it is parallel to the dip of the sandstones. This is the northern limb of the Middlesboro Syncline. Several gaps occur along Pine Mountain, these are caused by erosion along cross-cutting faults; these gaps include the gap at High Cliff, the Narrows gap at Pineville and Pound Gap near Jenkins, Kentucky. There are other minor gaps as well. Cumberland Mountain, not to be confused with the Cumberland Mountains within which it resides, is a long ridge extending from northeastern Tennessee, southeastern Kentucky and southwestern Virginia, its peak forms the boundary between Virginia in some areas. The southeastern side of Cumberland Mountain is a cliff-lined wall, a barrier to exploration and settlement in Kentucky during the westward expansion in the late eighteenth century.
The famous Cumberland Gap is one of several gaps along Cumberland Mountain that allowed access across the mountain. Cumberland Mountain is a long ridge running from near Caryville, northeastward to near Norton, Virginia, a distance of 97 miles; the southeastern slope of the ridge is cliff lined. The ridge is interrupted by several gaps, including Cumberland Gap, Big Creek Gap between Ivydell and LaFollette, Pennington Gap near Pennington Gap and Big Stone Gap near Big Stone Gap, Virginia; the crest of Cumberland Mountain ranges from 2,200 feet to 3,500 feet in elevation. Cumberland Mountain is parallel to Pine Mountain which lies from eight to ten miles to the northwest. Cumberland Mountain is part of the Cumberland Overthrust Sheet or block and is the northern limb of the Powell Valley Anticline, a ramp anticline; the ridge exists because hard Lee-type sandstones of Early Pennsylvanian Age crop out along this line. Softer rocks have been eroded away; the southwestern terminus of Cumberland Mountain is marked by the northwest-trending Jacksboro Fault, a lateral ramp fault.
The northwestern terminus is located near Norton, where the hard sandstones dip below the surface as the axis of the Powell Valley anticline plunges to the northeast. The various gaps in Cumberland Mountain are caused by rock weaknesses at cross-cutting faults or joints. For example, Cumberland Gap was caused by erosion along the cross-cutting Rocky Face Fault; the cliff-lined southeastern slope of Cumberland Mountain was created by erosion along the breached side of the Powell Valley Anticline. The more-gentle northwestern slope is the dip slope and parallel to the dip of the Early Pennsylvanian sandstones; this northwestward dip is the northern limb of the Powell Valley Anticline. Cumberland Mountain forms the drainage divide between the Cumberland River to the north and the Powell River to the south. Several mountains that lie between Pine Mountain and Cumberland Mountain include Black Mountain and Little Black Mountain as well as a number of smaller mountains (Short, Rich, Reynolds
A normal route or normal way is the most used route for ascending and descending a mountain peak. It is the simplest route. In the Alps, routes are classed in the following ways, based on their waymarking and upkeep: Footpaths Hiking trails Mountain trails Alpine routes Climbing routes and High Alpine routes in combined rock and ice terrain, graded by difficultySometimes the normal route is not the easiest ascent to the summit, but just the one, most used. There may be technically easier variations; this is the case on the Watzmannfrau, the Hochkalter and Mount Everest. There may be many reasons these easier options are less well-used: the simplest route is less well known than the normal route; the technically easiest route is more arduous than another and is therefore used on the descent. The technically easiest route carries a much higher risk of e.g. rockfalls or avalanche and is therefore avoided in favour of a more difficult route. The technically easier route requires a complicated or long approach march, or all access may be banned via one country.
The term tourist route may sometimes be applied by those wishing to suggest that other routes up a mountain are somehow more "worthy". This belittling of the "normal route" therefore maintains a distinction between those perceiving themselves as serious mountaineers who disparage the incursion of tourist climbers into their domain