The Signal Corps Laboratories ( SCL ) was a research installation under the command of the U.S. Army Signal Corps . Headquartered at Fort Monmouth, New Jersey , SCL directed research on electronics, radar, and communication systems for the U.S. Army . Throughout its history, SCL operated under many names as the organizational structure of the Signal Corps and the U.S. Army changed over time.
177-831: The Signal Corps Laboratories emerged as a result of declining economic conditions that compelled the U.S. Army Signal Corps to consolidate its widespread laboratories. By the late 1920s, the Signal Corps administered seven different major laboratories across the United States. In Washington, D.C. , it had the Signal Corps Electrical Laboratory, the Signal Corps Meteorological Laboratory, the Signal Corps Research Laboratory at
354-495: A cascading waterfall with Italian Renaissance -style architecture. Modern , Postmodern , contemporary , and other non-classical architectural styles are also seen in the city. The National Museum of African American History and Culture deeply contrasts the stone-based neoclassical buildings on the National Mall with a design that combines modern engineering with heavy inspiration from African art . The interior of
531-470: A fractal surface, such as rocks or soil, and are used by navigation radars. A radar beam follows a linear path in vacuum but follows a somewhat curved path in atmosphere due to variation in the refractive index of air, which is called the radar horizon . Even when the beam is emitted parallel to the ground, the beam rises above the ground as the curvature of the Earth sinks below the horizon. Furthermore,
708-403: A receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II . A key development was the cavity magnetron in
885-509: A referendum on D.C. statehood resulted in an 85% support among Washington, D.C., voters for it to become the nation's 51st state . In March 2017, the city's congressional delegate Eleanor Holmes Norton introduced a bill for statehood. Reintroduced in 2019 and 2021 as the Washington, D.C., Admission Act , the U.S. House of Representatives passed it in April 2021. After not progressing in
1062-424: A transmitter that emits radio waves known as radar signals in predetermined directions. When these signals contact an object they are usually reflected or scattered in many directions, although some of them will be absorbed and penetrate into the target. Radar signals are reflected especially well by materials of considerable electrical conductivity —such as most metals, seawater , and wet ground. This makes
1239-563: A 70-pound instrument package as high as 600,000 feet in order to obtain upper atmospheric data. During the late 1950s, SCL (then called the U.S. Army Signal Research and Development Laboratory) represented one of the major players on the U.S. side of the Space Race against the Soviet Union . The laboratory’s long history of advancements in electronic communications technology enabled SCL researchers to make significant contributions to
1416-813: A World War I Signal Corps officer who had died in 1936. Early in the war, the Fort Monmouth Signal Laboratory and Field Laboratories Number One and Two were collectively known as the Signal Corps General Development Laboratories (SCGDL). In March 1942, the U.S. Army was reorganized into three commands—the Army Ground Forces , the Army Air Forces , and the Army Service Forces —with the Signal Corps belonging in
1593-482: A different dielectric constant or diamagnetic constant from the first, the waves will reflect or scatter from the boundary between the materials. This means that a solid object in air or in a vacuum , or a significant change in atomic density between the object and what is surrounding it, will usually scatter radar (radio) waves from its surface. This is particularly true for electrically conductive materials such as metal and carbon fibre, making radar well-suited to
1770-540: A full radar system, that he called a telemobiloscope . It operated on a 50 cm wavelength and the pulsed radar signal was created via a spark-gap. His system already used the classic antenna setup of horn antenna with parabolic reflector and was presented to German military officials in practical tests in Cologne and Rotterdam harbour but was rejected. In 1915, Robert Watson-Watt used radio technology to provide advance warning of thunderstorms to airmen and during
1947-480: A fundamental component of SCL. At one point during the 1940s, SCL acquired Raytheon Manufacturing Company ’s AN/CPS-9 Storm Detection Radar , the first radar system designed specifically for meteorological use. Researchers at Evans Signal Laboratory were tasked with modifying the CPS-9 to suit the needs and requirements of the Army Air Forces (AAF) Weather Service . In 1948, the new weather radar successfully observed
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#17327803621682124-408: A garden-lined grand avenue about 1 mile (1.6 km) long and 400 feet (120 m) wide in an area that is now the National Mall inspired by the grounds at Versailles and Tuileries Gardens. In March 1792, President Washington dismissed L'Enfant due to conflicts with the three commissioners appointed to supervise the capital's construction. Andrew Ellicott , who worked with L'Enfant in surveying
2301-502: A modern glass exterior and heavy curvature. CityCenterDC is home to Palmer Alley, a pedestrian-only walkway, and houses several apartment buildings, restaurants, and luxury-brand storefronts with streamlined glass and metal facades. Outside Downtown D.C., architectural styles are more varied. Historic buildings are designed primarily in the Queen Anne , Châteauesque , Richardsonian Romanesque , Georgian Revival , Beaux-Arts , and
2478-749: A physics instructor at the Imperial Russian Navy school in Kronstadt , developed an apparatus using a coherer tube for detecting distant lightning strikes. The next year, he added a spark-gap transmitter . In 1897, while testing this equipment for communicating between two ships in the Baltic Sea , he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation. The German inventor Christian Hülsmeyer
2655-498: A proposal for further intensive research on radio-echo signals from moving targets to take place at NRL, where Taylor and Young were based at the time. Similarly, in the UK, L. S. Alder took out a secret provisional patent for Naval radar in 1928. W.A.S. Butement and P. E. Pollard developed a breadboard test unit, operating at 50 cm (600 MHz) and using pulsed modulation which gave successful laboratory results. In January 1931,
2832-732: A pulsed system, and the first such elementary apparatus was demonstrated in December 1934 by the American Robert M. Page , working at the Naval Research Laboratory . The following year, the United States Army successfully tested a primitive surface-to-surface radar to aim coastal battery searchlights at night. This design was followed by a pulsed system demonstrated in May 1935 by Rudolf Kühnhold and
3009-567: A rainstorm from a distance of 185 miles and tracked it as it passed over Fort Monmouth. The modified AN/CPS-9 was brought into service by the AAF Weather Service (redesignated as the Air Weather Service in 1946) in 1954 and installed at military bases around the world. In addition to weather prediction, SCL investigated the behavior of wind and the physical properties of the upper atmosphere, often in order to improve
3186-431: A relatively high homelessness rate, despite its high living standard compared to many American cities. Washington, D.C., is divided into four quadrants of unequal area: Northwest (NW) , Northeast (NE) , Southeast (SE) , and Southwest (SW) . The axes bounding the quadrants radiate from the U.S. Capitol. All road names include the quadrant abbreviation to indicate their location. House numbers generally correspond with
3363-442: A rescue. For similar reasons, objects intended to avoid detection will not have inside corners or surfaces and edges perpendicular to likely detection directions, which leads to "odd" looking stealth aircraft . These precautions do not totally eliminate reflection because of diffraction , especially at longer wavelengths. Half wavelength long wires or strips of conducting material, such as chaff , are very reflective but do not direct
3540-510: A series of advancements in multiple areas of weather research during the 1950s. Tasked with conducting high-altitude and upper-atmosphere research using various sounding rockets like the Nike-Cajun and the Arcas , WSSCA helped launch more than 8,000 rockets around the world. In 1957, researchers launched Loki II rockets into the air and used radar to track the drift of the metallic chaff that
3717-410: A significantly stronger source of infrared light than what was available. SCL subsequently moved onto heat detection and reflected radio waves. By 1935, Blair determined that the use of high-frequency radio pulses provided the most promising approach to radar detection. Once sent out, the radio pulse waves reflected off of metallic objects, and then a receiver could catch the returning pulses and determine
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#17327803621683894-595: A snowstorm in January 1772. Hurricanes or their remnants occasionally impact the area in late summer and early fall. However, they usually are weak by the time they reach Washington, partly due to the city's inland location. Flooding of the Potomac River , however, caused by a combination of high tide, storm surge, and runoff, has been known to cause extensive property damage in the Georgetown neighborhood of
4071-676: A special committee charged with beautifying Washington's ceremonial core. What became known as the McMillan Plan was finalized in 1901 and included relandscaping the Capitol grounds and the National Mall, clearing slums, and establishing a new citywide park system. The plan is thought to have largely preserved L'Enfant's intended design for the city. By law, the city's skyline is low and sprawling. The federal Height of Buildings Act of 1910 prohibits buildings with height exceeding
4248-449: A speed of 16,000 miles per hour through space. In addition, the satellite was capable of receiving a photograph transmitted from one ground station and re-transmitting the image to the other ground station with no substantial loss in quality. The program concluded after Courier 1B’s payload stopped responding to commands from the ground stations after completing 228 orbits in 17 days. Washington, D.C. Washington, D.C. , formally
4425-633: A stream valley that bisects the city. Established in 1890, it is the country's fourth-oldest national park and is home to a variety of plant and animal species, including raccoon, deer, owls, and coyotes. Other National Park Service properties include the Chesapeake and Ohio Canal National Historical Park , the National Mall and Memorial Parks , Theodore Roosevelt Island , Columbia Island , Fort Dupont Park , Meridian Hill Park , Kenilworth Park and Aquatic Gardens , and Anacostia Park . The District of Columbia Department of Parks and Recreation maintains
4602-677: A system might do, Wilkins recalled the earlier report about aircraft causing radio interference. This revelation led to the Daventry Experiment of 26 February 1935, using a powerful BBC shortwave transmitter as the source and their GPO receiver setup in a field while a bomber flew around the site. When the plane was clearly detected, Hugh Dowding , the Air Member for Supply and Research , was very impressed with their system's potential and funds were immediately provided for further operational development. Watson-Watt's team patented
4779-793: A tightly guarded secret within the U.S. military. In October 1936, Lieutenant Colonel Louis E. Bender of the Office of the Chief Signal Officer visited the research laboratories of the General Electric Company , the RCA Manufacturing Company , and the Bell Telephone Laboratories and concluded that commercial progress on radio detection lagged far behind that of the U.S. military laboratories. In December 1936, SCL conducted
4956-473: A variety of Victorian styles. Rowhouses are prominent in areas developed after the Civil War and typically follow Federal and late Victorian designs. Georgetown 's Old Stone House , built in 1765, is the oldest-standing building in the city. Founded in 1789, Georgetown University features a mix of Romanesque and Gothic Revival architecture . The Ronald Reagan Building is the largest building in
5133-526: A way to test the feasibility of creating a global military communications network through the use of satellites that could receive, store, and transmit information. Developed by SCL and managed by ARPA, the Courier 1B satellite had 19,200 solar cells covering the surface of the spacecraft, which stored the collected solar power in nickel-cadmium batteries . An internal clock ensured that the satellite only listened to radio transmissions while orbiting above one of
5310-514: A wide region and direct fighter aircraft towards targets. Marine radars are used to measure the bearing and distance of ships to prevent collision with other ships, to navigate, and to fix their position at sea when within range of shore or other fixed references such as islands, buoys, and lightships. In port or in harbour, vessel traffic service radar systems are used to monitor and regulate ship movements in busy waters. Meteorologists use radar to monitor precipitation and wind. It has become
5487-847: A writeup on the apparatus was entered in the Inventions Book maintained by the Royal Engineers. This is the first official record in Great Britain of the technology that was used in coastal defence and was incorporated into Chain Home as Chain Home (low) . Before the Second World War , researchers in the United Kingdom, France , Germany , Italy , Japan , the Netherlands , the Soviet Union , and
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5664-452: Is a simplification for transmission in a vacuum without interference. The propagation factor accounts for the effects of multipath and shadowing and depends on the details of the environment. In a real-world situation, pathloss effects are also considered. Frequency shift is caused by motion that changes the number of wavelengths between the reflector and the radar. This can degrade or enhance radar performance depending upon how it affects
5841-451: Is as follows, where F D {\displaystyle F_{D}} is Doppler frequency, F T {\displaystyle F_{T}} is transmit frequency, V R {\displaystyle V_{R}} is radial velocity, and C {\displaystyle C} is the speed of light: Passive radar is applicable to electronic countermeasures and radio astronomy as follows: Only
6018-911: Is generally popular among tourists and locals. In 2007, six of the top ten buildings in the American Institute of Architects ' ranking of America's Favorite Architecture were in the city: the White House , Washington National Cathedral , the Jefferson Memorial , the United States Capitol , the Lincoln Memorial , and the Vietnam Veterans Memorial . The neoclassical , Georgian , Gothic , and Modern styles are reflected among these six structures and many other prominent edifices in
6195-682: Is home to many national monuments and museums , located most prominently on or around the National Mall , including the Jefferson Memorial , the Lincoln Memorial , and the Washington Monument . It hosts 177 foreign embassies and serves as the headquarters for the World Bank , the International Monetary Fund , the Organization of American States , and other international organizations. Home to many of
6372-480: Is in plant hardiness zone 8a near downtown, and zone 7b elsewhere in the city. Summers are hot and humid with a July daily average of 79.8 °F (26.6 °C) and average daily relative humidity around 66%, which can cause moderate personal discomfort. Heat indices regularly approach 100 °F (38 °C) at the height of summer. The combination of heat and humidity in the summer brings very frequent thunderstorms, some of which occasionally produce tornadoes in
6549-567: Is intended. Radar relies on its own transmissions rather than light from the Sun or the Moon, or from electromagnetic waves emitted by the target objects themselves, such as infrared radiation (heat). This process of directing artificial radio waves towards objects is called illumination , although radio waves are invisible to the human eye as well as optical cameras. If electromagnetic waves travelling through one material meet another material, having
6726-477: Is sea level at the Potomac River. The geographic center of Washington is near the intersection of 4th and L streets NW. The district has 7,464 acres (30.21 km ) of parkland, about 19% of the city's total area, the second-highest among high-density U.S. cities after Philadelphia . The city's sizable parkland was a factor in the city being ranked as third in the nation for park access and quality in
6903-417: Is the range. This yields: This shows that the received power declines as the fourth power of the range, which means that the received power from distant targets is relatively very small. Additional filtering and pulse integration modifies the radar equation slightly for pulse-Doppler radar performance , which can be used to increase detection range and reduce transmit power. The equation above with F = 1
7080-548: The Air Corps Brigadier General Henry Arnold, and other government officials to Fort Monmouth for a showcase of the SCL radar’s capabilities. As part of the demonstration, a B-10 bomber plane was arranged to fly over Fort Monmouth under the cover of darkness in simulated “sneak raids.” The objective was for SCL personnel to point searchlights on the plane and have the target in sight the moment
7257-499: The Anacostia River to the east. Washington, D.C.'s street grid was extended, where possible, throughout the district starting in 1888. Georgetown's streets were renamed in 1895. Some streets are particularly noteworthy, including Pennsylvania Avenue , which connects the White House to the Capitol; and K Street, which houses the offices of many lobbying groups. Constitution Avenue and Independence Avenue , located on
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7434-1074: The Army Service Forces (ASF) during World War II, this group consisted of the Quartermaster Corp s, the Corps of Engineers , the Medical Department , the Ordnance Department , the Signal Corps , the Chemical Warfare Service , and the Transportation Corps . Even after the dissolution of the ASF in 1946, the Technical Services continued its operations, except for some changes—the Chemical Warfare Service
7611-800: The Canal Zone in Panama . As part of its duties, the organization was tasked with conducting high-altitude and upper-atmosphere research using various rockets. These included the Nike Cajun rocket, the Army tactical Loki rocket , and the Arcas rocket .On May 1, 1958, the White Sands Proving Ground was officially renamed White Sands Missile Range. By 1959, WSSCA was redesignated as the U.S. Army Signal Missile Support Agency (SMSA) after its size and scope of operations had doubled. SMSA
7788-646: The Compensated Emancipation Act in 1862, which ended slavery in the district, freeing about 3,100 slaves in the district nine months before the Emancipation Proclamation . In 1868, Congress granted the district's African American male residents the right to vote in municipal elections. By 1870, the district's population had grown 75% in a decade to nearly 132,000 people, yet the city still lacked paved roads and basic sanitation. Some members of Congress suggested moving
7965-714: The Continental Congress and under the Articles of Confederation . New York City was the first capital upon the adoption of the Constitution , succeeded by Philadelphia , which was capital from 1790 to 1800. On October 6, 1783, after the capital was forced by the Pennsylvania Mutiny of 1783 to move to Princeton, Congress resolved to consider a new location for it. The following day, Elbridge Gerry of Massachusetts moved "that buildings for
8142-536: The District of Columbia and commonly known as Washington or D.C. , is the capital city and federal district of the United States . The city is on the Potomac River , across from Virginia , and shares land borders with Maryland to its north and east. It was named after George Washington , the first president of the United States . The district is named after Columbia , the female personification of
8319-756: The District of Columbia Organic Act of 1801 , which officially organized the district and placed the entire territory under the exclusive control of the federal government. The area within the district was organized into two counties, the County of Washington to the east and north of the Potomac and the County of Alexandria to the west and south. After the Act's passage, citizens in the district were no longer considered residents of Maryland or Virginia, which ended their representation in Congress. On August 24, 1814, during
8496-987: The National Bureau of Standards , and the Photographic Laboratory at Fort Humphreys (now Fort Lesley J. McNair ). In addition, the Signal Corps Aircraft Radio Laboratory was located at Wright Field in Dayton, Ohio, the Subaqueous Sound Ranging Laboratory was stationed at Fort H. G. Wright in New York , and the Radio Laboratory was established at Fort Monmouth in New Jersey . In 1929, the Signal Corps transferred
8673-574: The Nyquist frequency , since the returned frequency otherwise cannot be distinguished from shifting of a harmonic frequency above or below, thus requiring: Or when substituting with F D {\displaystyle F_{D}} : As an example, a Doppler weather radar with a pulse rate of 2 kHz and transmit frequency of 1 GHz can reliably measure weather speed up to at most 150 m/s (340 mph), thus cannot reliably determine radial velocity of aircraft moving 1,000 m/s (2,200 mph). In all electromagnetic radiation ,
8850-429: The Pentagon ordered Lieutenant Colonel John H. DeWitt Jr ., the director of the Evans Signal Laboratory, to investigate whether such a weapon could be detected and tracked using radar. This mission happened to coincide with one of Dewitt’s personal projects, which was to demonstrate the feasibility of bouncing radio signals off the moon. In 1940, Dewitt had previously tried and failed to reflect ultrashort radio waves off
9027-419: The Potomac River forms the district's border with Virginia and has two major tributaries, the Anacostia River and Rock Creek . Tiber Creek , a natural watercourse that once passed through the National Mall , was fully enclosed underground during the 1870s. The creek also formed a portion of the now-filled Washington City Canal , which allowed passage through the city to the Anacostia River from 1815 until
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#17327803621689204-669: The RAF's Pathfinder . The information provided by radar includes the bearing and range (and therefore position) of the object from the radar scanner. It is thus used in many different fields where the need for such positioning is crucial. The first use of radar was for military purposes: to locate air, ground and sea targets. This evolved in the civilian field into applications for aircraft, ships, and automobiles. In aviation , aircraft can be equipped with radar devices that warn of aircraft or other obstacles in or approaching their path, display weather information, and give accurate altitude readings. The first commercial device fitted to aircraft
9381-423: The Twenty-third Amendment , passed in 1961. Washington, D.C. anchors the southern end of the Northeast megalopolis . As the seat of the U.S. federal government , the city is an important world political capital . The city hosts the buildings that house federal government headquarters, including the White House , the Capitol, the Supreme Court Building , and multiple federal departments and agencies . The city
9558-471: The U.S. Army Air Corps in 1937, the laboratories retained their responsibility for the development, procurement, supply, and maintenance of the Army’s meteorological equipment for decades. While the U.S. Air Force provided the Army with operational weather support, the Signal Corps served as the primary agent for Army meteorological research and development. The varied effects of weather on communications equipment ensured that meteorological activities remained
9735-428: The U.S. East Coast . The city has a total area of 68.34 square miles (177 km ), of which 61.05 square miles (158.1 km ) is land and 7.29 square miles (18.9 km ) (10.67%) is water. The district is bordered by Montgomery County, Maryland , to the northwest; Prince George's County, Maryland , to the east; Arlington County, Virginia , to the west; and Alexandria, Virginia , to the south. The south bank of
9912-423: The U.S. Weather Bureau , and the U.S. Naval Photographic Interpretation Center to determine if satellites could aid researchers on the study of the Earth’s weather. The TIROS-1 satellite was equipped with two television cameras that took pictures of the Earth’s cloud formations from above and sent them down to ground stations at Fort Monmouth and in Hawaii within a matter of minutes. Over the course of three months,
10089-1146: The United Kingdom , which allowed the creation of relatively small systems with sub-meter resolution. The term RADAR was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term radar has since entered English and other languages as an anacronym , a common noun, losing all capitalization . The modern uses of radar are highly diverse, including air and terrestrial traffic control, radar astronomy , air-defense systems , anti-missile systems , marine radars to locate landmarks and other ships, aircraft anti-collision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring, radar remote sensing , altimetry and flight control systems , guided missile target locating systems, self-driving cars , and ground-penetrating radar for geological observations. Modern high tech radar systems use digital signal processing and machine learning and are capable of extracting useful information from very high noise levels. Other systems which are similar to radar make use of other parts of
10266-412: The War of 1812 , British forces invaded and occupied the city after defeating an American force at Bladensburg . In retaliation for acts of destruction by American troops in the Canadas , the British set fire to government buildings in the city, gutting the United States Capitol , the Treasury Building , and the White House in what became known as the burning of Washington . However, a storm forced
10443-428: The Washington Metro stations and the Hirshhorn Museum and Sculpture Garden are designed with strong influence from the 20th-century Brutalism movement. The Smithsonian Institution Building is built of Seneca red sandstone in the Norman Revival style. The Old Post Office building, located on Pennsylvania Avenue and completed in 1899, was the first building in the city to have a steel frame structure and
10620-440: The electromagnetic spectrum . One example is lidar , which uses predominantly infrared light from lasers rather than radio waves. With the emergence of driverless vehicles, radar is expected to assist the automated platform to monitor its environment, thus preventing unwanted incidents. As early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov ,
10797-407: The reflective surfaces . A corner reflector consists of three flat surfaces meeting like the inside corner of a cube. The structure will reflect waves entering its opening directly back to the source. They are commonly used as radar reflectors to make otherwise difficult-to-detect objects easier to detect. Corner reflectors on boats, for example, make them more detectable to avoid collision or during
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#173278036216810974-472: The "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect (the common term for interference at the time) when aircraft flew overhead. By placing a transmitter and receiver on opposite sides of the Potomac River in 1922, U.S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through
11151-402: The 1850s. The Chesapeake and Ohio Canal starts in Georgetown and was used during the 19th century to bypass the Little Falls of the Potomac River, located at the northwest edge of the city at the Atlantic Seaboard fall line . The highest natural elevation in the district is 409 feet (125 m) above sea level at Fort Reno Park in upper northwest Washington, D.C. The lowest point
11328-413: The 1920s went on to lead the U.K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told
11505-410: The 2018 ParkScore ranking of the park systems of the nation's 100 most populous cities, according to Trust for Public Land , a non-profit organization. The National Park Service manages most of the 9,122 acres (36.92 km ) of city land owned by the U.S. government. Rock Creek Park is a 1,754-acre (7.10 km ) urban forest in Northwest Washington, which extends 9.3 miles (15.0 km) through
11682-504: The British to evacuate the city after just 24 hours. Most government buildings were repaired quickly, but the Capitol, which was largely under construction at the time, would not be completed in its current form until 1868. In the 1830s, the district's southern territory of Alexandria declined economically, due in part to its neglect by Congress. Alexandria was a major market in the domestic slave trade and pro-slavery residents feared that abolitionists in Congress would end slavery in
11859-405: The District from its founding. The building of Washington likely relied in significant part on slave labor, and slave receipts have been found for the White House, Capitol Building, and establishment of Georgetown University. The city became an important slave market and a center of the nation's internal slave trade . After its survey, the new federal city was constructed on the north bank of
12036-433: The District of Columbia. Shepherd authorized large projects that modernized the city but bankrupted its government. In 1874, Congress replaced the territorial government with an appointed three-member board of commissioners. In 1888, the city's first motorized streetcars began service. Their introduction generated growth in areas of the district beyond the City of Washington's original boundaries, leading to an expansion of
12213-480: The Eatontown Signal Laboratory was transferred from the Signal Corps to the Army Air Forces. The facility would later be renamed to Watson Laboratories and moved to Rome, New York in 1951. In April 1945, a general order by the U.S. Department of War renamed Camp Coles to Coles Signal Laboratory and Camp Evans to Evans Signal Laboratory. Two months later, Fort Monmouth Signal Laboratory was redesignated as Squier Signal Laboratory in honor of Major General George Owen Squier,
12390-433: The Eatontown Signal Laboratory. Field Laboratory Number Three acted as one of the principal facilities for radar research, development, and testing during World War II. Due to the significant military importance of radar at the time, the Office of the Chief Signal Officer made efforts to keep the covert activities of Field Laboratory Number Three separate from SCL’s general operations. Known as the Signal Corps Radar Laboratory,
12567-436: The Electrical Laboratory, the Meteorological Laboratory, and the Research Laboratory at the Bureau of Standards to Fort Monmouth where the Radio Laboratory resided. In 1930, the Subaqueous Sound Ranging Laboratory was also moved from Fort H. G. Wright to Fort Monmouth. Together, these five laboratories formed the consolidated Signal Corps Laboratories. Initially, nine wooden buildings built in 1918 housed SCL operations. However,
12744-475: The Greek goddess of the moon. Rather than designing an entirely new device for this project, Dewitt and his team modified an existing SCR-271 radar set to serve as the transmitter. The 40-foot square bedspring antenna array was mounted atop a 30-meter tower at Fort Monmouth and aimed at the moon. Since the antenna had only azimuth control, the team only had a narrow window of 40 minutes each day for experiments while
12921-444: The Potomac River, to the east of Georgetown centered on Capitol Hill . On September 9, 1791, three commissioners overseeing the capital's construction named the city in honor of President Washington. The same day, the federal district was named Columbia, a feminine form of Columbus , which was a poetic name for the United States commonly used at that time. Congress held its first session there on November 17, 1800. Congress passed
13098-462: The Residence Act, the exact location was to be selected by President George Washington , who signed the bill into law on July 16, 1790. Formed from land donated by Maryland and Virginia, the initial shape of the federal district was a square measuring 10 miles (16 km) on each side and totaling 100 square miles (259 km ). Two pre-existing settlements were included in the territory,
13275-608: The Senate and signed by president; it would have renamed the city Washington, Douglas Commonwealth and shrunk the Federal District to about the size of the national mall. Designed in 1791 by Pierre Charles L'Enfant , the city is divided into quadrants , which are centered around the Capitol Building and include 131 neighborhoods . As of the 2020 census , the city had a population of 689,545. Commuters from
13452-470: The Senate, the statehood bill was introduced again in January 2023. The bill would have made D.C. into a state with one representative and two senators, with the name Washington, Douglas Commonwealth (thus keeping the same abbreviation Washington, D.C.). The legalities, reasons, and impact of statehood have been heavily debated in the 2020s. Washington, D.C., is located in the Mid-Atlantic region of
13629-406: The Signal Corps was responsible for reporting the weather and other meteorological information to the Army for the purposes of long-range artillery and antiaircraft support, storm tracking, and general operational planning. In 1929, the Signal Corps oversaw the launch of the first radio-equipped weather balloon at Fort Monmouth. Although SCL lost its official weather reporting and forecasting duties to
13806-558: The Signal Corps,” and substantial funding was provided to SCL to continue the development of its radar technology. SCL subsequently developed the SCR-268 , a short-range radar set designed to control searchlights and antiaircraft guns. The SCR-268 was formally accepted by the Army after successful tests at Fort Monroe, Virginia , in 1938. At the request of the Air Corps, SCL also developed two radar sets for long-range aircraft detection,
13983-469: The U.S. Army Signal Research and Development Laboratory (USASRDL). In that same year, USASRDL created the Institute for Exploratory Research to place greater emphasis on internal research. The first recorded activity of SCEL at White Sands Missile Range (WSMR) was on April 2, 1946, when the Signal Corps deployed a team of 10 men to the then-named White Sands Proving Ground (WSPG) to assist the testing of
14160-911: The United States Constitution was ratified in 1961, granting the district three votes in the Electoral College for the election of president and vice president, but still not affording the city's residents representation in Congress. After the assassination of civil rights leader Martin Luther King Jr. on April 4, 1968, riots broke out in the city , primarily in the U ;Street, 14th Street, 7th Street, and H Street corridors, which were predominantly black residential and commercial areas. The riots raged for three days until more than 13,600 federal troops and Washington, D.C., Army National Guardsmen stopped
14337-724: The United States, independently and in great secrecy, developed technologies that led to the modern version of radar. Australia, Canada, New Zealand, and South Africa followed prewar Great Britain's radar development, Hungary and Sweden generated its radar technology during the war. In France in 1934, following systematic studies on the split-anode magnetron , the research branch of the Compagnie générale de la télégraphie sans fil (CSF) headed by Maurice Ponte with Henri Gutton, Sylvain Berline and M. Hugon, began developing an obstacle-locating radio apparatus, aspects of which were installed on
14514-439: The United States. Following the use of atomic weapons against Japan in 1945, the U.S. military began worrying about the type of weapons that might threaten the nation in the future. Back in 1943, General Henry “Hap” Arnold forewarned the emergence of projectiles that could fly at speeds too fast to detect and be powerful enough to wipe out an entire city—an early prediction of the intercontinental ballistic missile . In 1945,
14691-448: The ability to observe and measure the distance of nearby astronomical objects by analyzing their reflections. It eventually led to the accurate topographical mapping of the moon and planets, the measurement and analysis of the ionosphere, and the development of satellites. The development of new meteorological technologies and techniques have long been a staple function of the Signal Corps and its laboratory installations. Since World War I,
14868-513: The already-implemented L'Enfant Plan , with the new McMillan Plan leading urban development in the city throughout the movement. Much of the old Victorian Mall was replaced with modern Neoclassical and Beaux-Arts architecture ; these designs are still prevalent in the city's governmental buildings today. Increased federal spending under the New Deal in the 1930s led to the construction of new government buildings, memorials, and museums in
15045-504: The area. Blizzards affect Washington once every four to six years on average. The most violent storms, known as nor'easters , often impact large regions of the East Coast . From January 27 to 28, 1922 , the city officially received 28 inches (71 cm) of snowfall, the largest snowstorm since official measurements began in 1885. According to notes kept at the time, the city received between 30 and 36 inches (76 and 91 cm) from
15222-537: The arrest of Oshchepkov and his subsequent gulag sentence. In total, only 607 Redut stations were produced during the war. The first Russian airborne radar, Gneiss-2 , entered into service in June 1943 on Pe-2 dive bombers. More than 230 Gneiss-2 stations were produced by the end of 1944. The French and Soviet systems, however, featured continuous-wave operation that did not provide the full performance ultimately synonymous with modern radar systems. Full radar evolved as
15399-479: The beam path caused the received signal to fade in and out. Taylor submitted a report, suggesting that this phenomenon might be used to detect the presence of ships in low visibility, but the Navy did not immediately continue the work. Eight years later, Lawrence A. Hyland at the Naval Research Laboratory (NRL) observed similar fading effects from passing aircraft; this revelation led to a patent application as well as
15576-618: The capital farther west, but President Ulysses S. Grant refused to consider the proposal. In the Organic Act of 1871 , Congress repealed the individual charters of the cities of Washington and Georgetown , abolished Washington County , and created a new territorial government for the whole District of Columbia. These steps made "the city of Washington...legally indistinguishable from the District of Columbia." In 1873, President Grant appointed Alexander Robey Shepherd as Governor of
15753-608: The capital. In the Compromise of 1790 , Madison, Alexander Hamilton , and Thomas Jefferson agreed that the federal government would pay each state's remaining Revolutionary War debts in exchange for establishing the new national capital in the Southern United States . On July 9, 1790, Congress passed the Residence Act , which approved the creation of a national capital on the Potomac River . Under
15930-784: The captured German V-2 rockets . By 1949, the U.S. Department of the Army established the SCEL Field Station No. 1 at Fort Bliss, Texas as a class II activity. Field Station No. 1 pioneered research in radar tracking and communication systems to provide support for the early missile programs at WSPG. In 1952, Field Station No. 1 was reorganized into the White Sands Signal Corps Agency (WSSCA), which sought to improve munition performance by conducting high altitude and upper-atmosphere research. In 1954, WSSCA expanded to form three teams: one at Yuma Proving Ground , one at Dugway Proving Ground , and one at
16107-565: The city's 900 acres (3.6 km ) of athletic fields and playgrounds, 40 swimming pools, and 68 recreation centers. The U.S. Department of Agriculture operates the 446-acre (1.80 km ) United States National Arboretum in Northeast Washington, D.C. Washington's climate is humid subtropical ( Köppen : Cfa ), or oceanic ( Trewartha : Do bordering Cf downtown). Winters are cool to cold with some snow of varying intensity, while summers are hot and humid. The district
16284-402: The city's Maryland and Virginia suburbs raise the city's daytime population to more than one million during the workweek. The Washington metropolitan area , which includes parts of Maryland, Virginia, and West Virginia , is the country's seventh-largest metropolitan area , with a 2023 population of 6.3 million residents. A locally elected mayor and 13-member council have governed
16461-730: The city's classical-style architecture include buildings constructed in the French Second Empire style, including the Eisenhower Executive Office Building , and the modernist Watergate complex . The Thomas Jefferson Building , the main Library of Congress building, and the historic Willard Hotel are built in Beaux-Arts style , popular throughout the world in the late nineteenth and early twentieth centuries. Meridian Hill Park contains
16638-421: The city, was then tasked with completing its design. Though Ellicott revised the original L'Enfant plans, including changing some street patterns, L'Enfant is still credited with the city's overall design. By the early 20th century, however, L'Enfant's vision of a grand national capital was marred by slums and randomly placed buildings in the city, including a railroad station on the National Mall. Congress formed
16815-590: The city. Many of the government buildings, monuments, and museums along the National Mall and surrounding areas are heavily inspired by classical Roman and Greek architecture. The designs of the White House, the U.S. Capitol, Supreme Court Building , Washington Monument , National Gallery of Art , Lincoln Memorial, and Jefferson Memorial are all heavily drawn from these classical architectural movements and feature large pediments, domes, columns in classical order, and heavy stone walls. Notable exceptions to
16992-469: The city. Precipitation occurs throughout the year. The highest recorded temperature was 106 °F (41 °C) on August 6, 1918, and on July 20, 1930. The lowest recorded temperature was −15 °F (−26 °C) on February 11, 1899 , right before the Great Blizzard of 1899 . During a typical year, the city averages about 37 days at or above 90 °F (32 °C) and 64 nights at or below
17169-439: The design and development of communications equipment and the improvement of meteorological services. Much of its research pushed the boundaries of radio technology, so much so that the Signal Corps employed a standard nomenclature for radio technology where each item began with the letters “SCR.” These letters originally stood for “set, complete, radio” but instead came to signify “Signal Corps radio.” During its early years, SCL
17346-408: The detection of aircraft and ships. Radar absorbing material , containing resistive and sometimes magnetic substances, is used on military vehicles to reduce radar reflection . This is the radio equivalent of painting something a dark colour so that it cannot be seen by the eye at night. Radar waves scatter in a variety of ways depending on the size (wavelength) of the radio wave and the shape of
17523-476: The detection process. As an example, moving target indication can interact with Doppler to produce signal cancellation at certain radial velocities, which degrades performance. Sea-based radar systems, semi-active radar homing , active radar homing , weather radar , military aircraft, and radar astronomy rely on the Doppler effect to enhance performance. This produces information about target velocity during
17700-411: The detection process. This also allows small objects to be detected in an environment containing much larger nearby slow moving objects. Doppler shift depends upon whether the radar configuration is active or passive. Active radar transmits a signal that is reflected back to the receiver. Passive radar depends upon the object sending a signal to the receiver. The Doppler frequency shift for active radar
17877-626: The device in patent GB593017. Development of radar greatly expanded on 1 September 1936, when Watson-Watt became superintendent of a new establishment under the British Air Ministry , Bawdsey Research Station located in Bawdsey Manor , near Felixstowe, Suffolk. Work there resulted in the design and installation of aircraft detection and tracking stations called " Chain Home " along the East and South coasts of England in time for
18054-482: The district . Alexandria's citizens petitioned Virginia to retake the land it had donated to form the district, a process known as retrocession . The Virginia General Assembly voted in February 1846, to accept the return of Alexandria. On July 9, 1846, Congress went further, agreeing to return all territory that Virginia had ceded to the district during its formation. This left the district's area consisting only of
18231-548: The district over the next few decades. Georgetown's street grid and other administrative details were formally merged with those of the City of Washington in 1895. However, the city had poor housing and strained public works, leading it to become the first city in the nation to undergo urban renewal projects as part of the City Beautiful movement in the early 20th century. The City Beautiful movement built heavily upon
18408-425: The district since 1973, though Congress retains the power to overturn local laws. Washington, D.C., residents are, on the federal level, politically disenfranchised since the city's residents do not have voting representation in Congress; the city's residents elect a single non-voting congressional delegate to the U.S. House of Representatives. The city's voters choose three presidential electors in accordance with
18585-505: The district with a total area of about 3.1 million square feet (288,000 m ). Washington Union Station is designed in a combination of architectural styles. Its Great Hall has elaborate gold leaf designs along the ceilings and the hall includes several decorative classical-style statues. Radar Radar is a system that uses radio waves to determine the distance ( ranging ), direction ( azimuth and elevation angles ), and radial velocity of objects relative to
18762-523: The district, though the chairman of the House Subcommittee on District Appropriations, Ross A. Collins of Mississippi , justified cuts to funds for welfare and education for local residents by saying that "my constituents wouldn't stand for spending money on niggers." World War II led to an expansion of federal employees in the city; by 1950, the district's population reached its peak of 802,178 residents. The Twenty-third Amendment to
18939-575: The effort concentrated on finding a way to detect an airplane and its position at night. However, after a conference in January 1930 with representatives of the Coast Artillery Corps and the Signal Corps, the Ordnance Department agreed to transfer its radar work and equipment to the Signal Corps. In February 1931, SCL Director Major William R. Blair established Project 88, “Position Finding by Means of Light,” to continue
19116-538: The electric field is perpendicular to the direction of propagation, and the electric field direction is the polarization of the wave. For a transmitted radar signal, the polarization can be controlled to yield different effects. Radars use horizontal, vertical, linear, and circular polarization to detect different types of reflections. For example, circular polarization is used to minimize the interference caused by rain. Linear polarization returns usually indicate metal surfaces. Random polarization returns usually indicate
19293-473: The entire area in front of it, and then used one of Watson-Watt's own radio direction finders to determine the direction of the returned echoes. This fact meant CH transmitters had to be much more powerful and have better antennas than competing systems but allowed its rapid introduction using existing technologies. A key development was the cavity magnetron in the UK, which allowed the creation of relatively small systems with sub-meter resolution. Britain shared
19470-582: The facility was established at Fort Hancock in Sandy Hook, New Jersey , but work also took place near Sandy Hook in the boroughs of Rumson and Highlands . However, confusion over the sanction of the word “radar” prompted the U.S. Department of War to move the installation to a site in Belmar, New Jersey , where it operated under a different name. The field laboratory site was soon designated as Camp Evans in 1942 in honor of Lieutenant Colonel Paul W. Evans,
19647-414: The field test of its preliminary radar system, including the 75-watt transmitter, near Newark Airport in New Jersey to determine if it could detect the commercial airplanes flying in the sky. Researchers beamed radio pulses from the transmitter along the general flight path of the planes, while a receiver was set up a mile away. The experiment proved to be a success, and Blair wrote a letter to Bender with
19824-466: The firm GEMA [ de ] in Germany and then another in June 1935 by an Air Ministry team led by Robert Watson-Watt in Great Britain. In 1935, Watson-Watt was asked to judge recent reports of a German radio-based death ray and turned the request over to Wilkins. Wilkins returned a set of calculations demonstrating the system was basically impossible. When Watson-Watt then asked what such
20001-407: The first session in the unfinished Capitol Building in 1800 after the capital moved from Philadelphia . In 1801, the District of Columbia, formerly part of Maryland and Virginia and including the existing settlements of Georgetown and Alexandria , was officially recognized as the federal district; initially, the city was a separate settlement within the larger district. In 1846, Congress returned
20178-684: The first to use electrical wiring in its design. Notable contemporary residential buildings, restaurants, shops, and office buildings in the city include the Wharf on the Southwest Waterfront , Navy Yard along the Anacostia River , and CityCenterDC in Downtown . The Wharf has seen the construction of several high-rise office and residential buildings overlooking the Potomac River . Additionally, restaurants, bars, and shops have been opened at street level. Many of these buildings have
20355-474: The following text: “You will be interested to know that yesterday, December 14, we succeeded in locating an airplane by the pulse method over a range of approximately 0 to 7 miles.” Following the field test, SCL improved the antenna systems for both the transmitter and the receivers in order to multiply the power of the transmitter beam and obtain more accurate readings of the target. In May 1937, Blair invited Secretary of War Harry H. Woodring , Assistant Chief of
20532-832: The founder of SCL and Chief Signal Officer during World War I. Most notably, the Signal Corps Ground Service was reorganized into the Signal Corps Engineering Laboratories (SCEL) in May 1945. With the absence of the Eatontown Signal Laboratory, SCEL consisted of the newly named Squier Signal Laboratory, Coles Signal Laboratory, and Evans Signal Laboratory. As a consolidated laboratory, SCEL prioritized research pertaining to communication systems, radar , electron tubes, and component improvement as well as meteorology , proximity fuzes , and photography. While
20709-407: The four-story tall building exhibited only four sides and permanently lacked two of its six intended sides. Upon consolidation, the individual laboratories of SCEL were divided into seven divisions: Communications, Radar, Countermeasures, Physical Sciences, Electron Devices, Production and Maintenance Engineering, and Components, Materials and Power Sources. In 1958, the U.S. Army redesignated SCEL as
20886-404: The freezing mark (32 °F or 0 °C). On average, the first day with a minimum at or below freezing is November 18 and the last day is March 27. Washington, D.C., was a planned city , and many of the city's street grids were developed in that initial plan. In 1791, President George Washington commissioned Pierre Charles L'Enfant , a French-born military engineer and artist, to design
21063-454: The ground stations, operators relayed hundreds of thousands of words in teletypewriter code to the satellite. When Courier 1B passed over the other ground station, it transmitted the entire message to the operators at that station. This process of receiving and transmitting radio messages could also happen at the same time. Operators determined that Courier 1B could simultaneously receive and transmit about 68,000 words per minute while traveling at
21240-408: The guidance and control of missiles. Radiosondes equipped to high-altitude balloons were used to measure humidity, temperature, and pressure more than 20 miles high up in the atmosphere. For altitudes above that, SCL researchers in the post-WWII era used rockets to conduct atmospheric studies and collect data. The White Sands Signal Corps Agency, which originated as an SCEL field station, experienced
21417-460: The land originally ceded by Virginia , including the city of Alexandria. In 1871, it created a single municipality for the remaining portion of the district. There have been several unsuccessful efforts to make the district into a state since the 1880s; a statehood bill passed the House of Representatives in 2021 but was not adopted by the U.S. Senate . To become law it would have to be passed by
21594-506: The last category. Then, nine months later in December, the operations at Fort Monmouth Signal Laboratory, Camp Coles, Eatontown Signal Laboratory, and Camp Evans were consolidated to form the Signal Corps Ground Service. By this point, SCL possessed a personnel strength of over 14,500 military and civilian personnel. Following World War II, SCL and its field laboratories underwent several structural changes, as well as name changes, in order to better organize their activities. In February 1945,
21771-571: The launch of the first communications satellite in the world. Launched on December 18, 1958, the SCORE satellite was jointly developed by SCL and the Advanced Research Projects Agency (ARPA) with help from the U.S. Air Force. The spacecraft carried a communications package designed and built by SCL that contained a tape recording of President Dwight D. Eisenhower ’s Christmas greeting to the world. This message of good will
21948-429: The mission on detecting airplanes. The word “light” in the project title referred to electromagnetic radiation , particularly infrared light . The undertaking initially focused on the use of reflected infrared waves as a potential form of radar detection. However, Blair abandoned the reflected infrared method in 1933 after researchers discovered that tracking a target to a distance of 32,000 feet using this method required
22125-600: The mobile SCR-270 and the fixed SCR-271. Both the SCR-270 and the SCR-271 had a range of 120 miles and constituted the backbone of the Aircraft Warning Service by the time the United States entered World War II. SCL continued its highly classified research and development activities on radar at its field laboratories during the war, with Camp Evans becoming one of the principal facilities for radar work in
22302-424: The moon in an attempt to expand the study of the ionosphere . This time, Dewitt assembled a team of five people, including mathematician Walter McAfee , to push the boundaries of how far electronic signals can be transmitted into the upper atmosphere. In place of incoming ballistic missiles, the team chose the moon as the target of their radio signals. As a result, the undertaking was named Project Diana in honor of
22479-407: The moon was in the prime location as it was rising or setting. After several unsuccessful attempts, the team detected the first signals reflected back from the rising moon on January 10, 1946, at 11:58 am. Traveling at the speed of light, the radio waves from the modified array took about 2.5 seconds to travel from Fort Monmouth to the moon and back, a distance of over 800,000 kilometers. The experiment
22656-409: The nation . The U.S. Constitution in 1789 called for the creation of a federal district under the exclusive jurisdiction of the U.S. Congress . As such, Washington, D.C., is not part of any state , and is not one itself. The Residence Act , adopted on July 16, 1790, approved the creation of the capital district along the Potomac River. The city was founded in 1791, and the 6th Congress held
22833-546: The nation's largest industry associations, non-profit organizations, and think tanks , D.C. is known as a lobbying hub, with K Street as the industry center. The city had 20.7 million domestic visitors and 1.2 million international visitors, ranking seventh among U.S. cities as of 2022. The Algonquian -speaking Piscataway people , also known as the Conoy, inhabited the lands around the Potomac River and present-day Washington, D.C., when Europeans first arrived and colonized
23010-405: The nation’s entry into the second World War . From 1940 to 1941, the Signal Corps established three field laboratories near Fort Monmouth to supplement the expanding research efforts of SCL. Field Laboratory Number One was situated west of Red Bank, New Jersey , and was primarily responsible for the development of ground communications technologies and radio equipment. Spanning 46 acres, the site
23187-474: The need for more space led Colonel William R. Blair , the first director of the consolidated laboratories, to arrange the construction of a permanent laboratory building in 1934. When construction finished in 1935, the newly built facility was designated as the Fort Monmouth Signal Laboratory. In light of the ongoing war in Europe, military interest in the United States reached a feverish level as many anticipated
23364-469: The need for the national government not to rely on any state for its own security. Article One, Section Eight of the Constitution permits the establishment of a "District (not exceeding ten miles square) as may, by cession of particular states, and the acceptance of Congress, become the seat of the government of the United States". However, the constitution does not specify a location for
23541-580: The new but incomplete Albert J. Myer Center in the Charles Woods Area of Fort Monmouth. Named in honor of the first Chief Signal Officer of the U.S. Army Signal Corps, the new facility was commonly referred to as the Hexagon due to the building’s unique six-sided shape. However, the Albert J. Myer Center never realized its planned hexagon shape, purportedly due to misappropriated funds. As a result,
23718-496: The new capital. He enlisted the help of Isaac Roberdeau, Étienne Sulpice Hallet and Scottish surveyor Alexander Ralston to help lay out the city plan. The L'Enfant Plan featured broad streets and avenues radiating out from rectangles, providing room for open space and landscaping. L'Enfant was also provided a roll of maps by Thomas Jefferson depicting Frankfurt, Amsterdam, Strasbourg, Paris, Orleans, Bordeaux, Lyon, Marseille, Turin, and Milan. L'Enfant's design also envisioned
23895-552: The north and south sides of the National Mall, respectively, are home to many of Washington's iconic museums, including many Smithsonian Institution buildings and the National Archives Building . Washington hosts 177 foreign embassies ; these maintain nearly 300 buildings and more than 1,600 residential properties, many of which are on a section of Massachusetts Avenue informally known as Embassy Row . The architecture of Washington, D.C., varies greatly and
24072-404: The number of blocks away from the Capitol. Most streets are set out in a grid pattern with east–west streets named with letters (e.g., C Street SW), north–south streets with numbers (e.g., 4th Street NW), and diagonal avenues, many of which are named after states . The City of Washington was bordered on the north by Boundary Street (renamed Florida Avenue in 1890); Rock Creek to the west, and
24249-508: The ocean liner Normandie in 1935. During the same period, Soviet military engineer P.K. Oshchepkov , in collaboration with the Leningrad Electrotechnical Institute , produced an experimental apparatus, RAPID, capable of detecting an aircraft within 3 km of a receiver. The Soviets produced their first mass production radars RUS-1 and RUS-2 Redut in 1939 but further development was slowed following
24426-421: The operational control of SCEL at Fort Monmouth. In 1962, the U.S. Army went through a dramatic reorganization of its internal structure in response to a study directed by Secretary of Defense Robert McNamara . At the time, the Signal Corps belonged to the Technical Services, a coalition of independently administered agencies that supplied weapons, equipment, and services to the Army. Originally created as part of
24603-531: The outbreak of World War II in 1939. This system provided the vital advance information that helped the Royal Air Force win the Battle of Britain ; without it, significant numbers of fighter aircraft, which Great Britain did not have available, would always have needed to be in the air to respond quickly. The radar formed part of the " Dowding system " for collecting reports of enemy aircraft and coordinating
24780-465: The payload of several successful satellites . In 1955, the same year that the United States announced its intentions to launch artificial satellites into space, SCL began testing the application of solar cells for satellites. The effort culminated in the development of solar cells to power the Vanguard I satellite. As a result, Vanguard I became the first solar-powered satellite in the world when it
24957-413: The personnel strength of SCEL had dropped significantly after the war, the existing laboratory buildings were not large enough to house the laboratories’ growing workforce. By 1952, the laboratory buildings had reached maximum capacity, and the Signal Corps began planning the construction of a new laboratory building to consolidate all SCEL activities. In 1954, the Signal Corps began moving SCEL operations to
25134-568: The port of Georgetown , founded in 1751, and the port city of Alexandria, Virginia , founded in 1749. In 1791 and 1792, a team led by Andrew Ellicott , including Ellicott's brothers Joseph and Benjamin and African American astronomer Benjamin Banneker , whose parents had been enslaved, surveyed the borders of the federal district and placed boundary stones at every mile point; many of these stones are still standing. Both Maryland and Virginia were slave states , and slavery existed in
25311-480: The portion originally donated by Maryland. Confirming the fears of pro-slavery Alexandrians, the Compromise of 1850 outlawed the slave trade in the district, although not slavery itself. The outbreak of the American Civil War in 1861 led to the expansion of the federal government and notable growth in the city's population, including a large influx of freed slaves. President Abraham Lincoln signed
25488-478: The position, speed, and direction of the metallic objects. In June 1936, SCL developed a 75-watt breadboard model transmitter, an early precursor to the first Army radars. By this point, SCL and the Naval Research Laboratory decided to share information on developments of their respective radar systems to avoid duplication of effort. Nevertheless, the research and development of radar remained
25665-706: The primary tool for short-term weather forecasting and watching for severe weather such as thunderstorms , tornadoes , winter storms , precipitation types, etc. Geologists use specialized ground-penetrating radars to map the composition of Earth's crust . Police forces use radar guns to monitor vehicle speeds on the roads. Automotive radars are used for adaptive cruise control and emergency breaking on vehicles by ignoring stationary roadside objects that could cause incorrect brake application and instead measuring moving objects to prevent collision with other vehicles. As part of Intelligent Transport Systems , fixed-position stopped vehicle detection (SVD) radars are mounted on
25842-432: The radial component of the velocity is relevant. When the reflector is moving at right angle to the radar beam, it has no relative velocity. Objects moving parallel to the radar beam produce the maximum Doppler frequency shift. When the transmit frequency ( F T {\displaystyle F_{T}} ) is pulsed, using a pulse repeat frequency of F R {\displaystyle F_{R}} ,
26019-538: The region in the early 17th century. The Nacotchtank , also called the Nacostines by Catholic missionaries , maintained settlements around the Anacostia River in present-day Washington, D.C. Conflicts with European colonists and neighboring tribes ultimately displaced the Piscataway people, some of whom established a new settlement in 1699 near Point of Rocks, Maryland . Nine cities served as capitals to
26196-547: The research and development operations previously helmed by the Signal Corps. Under ECOM, the USASRDL was renamed to the U.S. Army Electronics Research and Development Laboratory that same year. In addition, SMSA became a part of the Electronics Research and Development Activity (ERDA) at WSMR under ECOM. During the restructuring of ECOM in 1964, however, the U.S. Army Electronics Research and Development Laboratory
26373-414: The response. Given all required funding and development support, the team produced working radar systems in 1935 and began deployment. By 1936, the first five Chain Home (CH) systems were operational and by 1940 stretched across the entire UK including Northern Ireland. Even by standards of the era, CH was crude; instead of broadcasting and receiving from an aimed antenna, CH broadcast a signal floodlighting
26550-410: The resulting frequency spectrum will contain harmonic frequencies above and below F T {\displaystyle F_{T}} with a distance of F R {\displaystyle F_{R}} . As a result, the Doppler measurement is only non-ambiguous if the Doppler frequency shift is less than half of F R {\displaystyle F_{R}} , called
26727-427: The roadside to detect stranded vehicles, obstructions and debris by inverting the automotive radar approach and ignoring moving objects. Smaller radar systems are used to detect human movement . Examples are breathing pattern detection for sleep monitoring and hand and finger gesture detection for computer interaction. Automatic door opening, light activation and intruder sensing are also common. A radar system has
26904-661: The same time, ECOM established the Institute for Exploratory Research. The Electronic Components Laboratory and the Institute for Exploratory Research would later merge to become the Electronics Technology and Devices Laboratory , and Vulnerability Assessment Laboratory would eventually emerge out from the Electronic Warfare Laboratory. Upon consolidation, the Signal Corps Laboratories was primarily responsible for
27081-603: The satellite transmitted more than 22,952 pictures. The success of the TIROS program demonstrated the value of satellites for weather forecasting and meteorology. Around the same time as Project TIROS, SCL also helmed the Courier program, which performed communications experiments involving the Courier 1B satellite following its launch into orbit on October 4, 1960. The Courier program was first proposed by SCL in September 1958 as
27258-407: The scattered energy back toward the source. The extent to which an object reflects or scatters radio waves is called its radar cross-section . The power P r returning to the receiving antenna is given by the equation: where In the common case where the transmitter and the receiver are at the same location, R t = R r and the term R t ² R r ² can be replaced by R , where R
27435-434: The searchlights were turned on. On the evening of May 26, the attendees watched SCL personnel use various radio pulse equipment in conjunction with the laboratories’ heat detector to track the plane. Each time the aircraft approached within range of the radar, its position was determined and the searchlights followed the plane over the base. Impressed by the demonstration, Woodring praised the “amazing scientific advances made by
27612-416: The site. It is a radiodetermination method used to detect and track aircraft , ships , spacecraft , guided missiles , motor vehicles , map weather formations , and terrain . A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna , a receiving antenna (often the same antenna is used for transmitting and receiving) and
27789-491: The target. If the wavelength is much shorter than the target's size, the wave will bounce off in a way similar to the way light is reflected by a mirror . If the wavelength is much longer than the size of the target, the target may not be visible because of poor reflection. Low-frequency radar technology is dependent on resonances for detection, but not identification, of targets. This is described by Rayleigh scattering , an effect that creates Earth's blue sky and red sunsets. When
27966-585: The technology with the U.S. during the 1940 Tizard Mission . In April 1940, Popular Science showed an example of a radar unit using the Watson-Watt patent in an article on air defence. Also, in late 1941 Popular Mechanics had an article in which a U.S. scientist speculated about the British early warning system on the English east coast and came close to what it was and how it worked. Watson-Watt
28143-879: The transmitter. The reflected radar signals captured by the receiving antenna are usually very weak. They can be strengthened by electronic amplifiers . More sophisticated methods of signal processing are also used in order to recover useful radar signals. The weak absorption of radio waves by the medium through which they pass is what enables radar sets to detect objects at relatively long ranges—ranges at which other electromagnetic wavelengths, such as visible light , infrared light , and ultraviolet light , are too strongly attenuated. Weather phenomena, such as fog, clouds, rain, falling snow, and sleet, that block visible light are usually transparent to radio waves. Certain radio frequencies that are absorbed or scattered by water vapour, raindrops, or atmospheric gases (especially oxygen) are avoided when designing radars, except when their detection
28320-567: The two designated ground stations in either Fort Monmouth or Salinas, Puerto Rico . Over the course of one orbit, Courier 1B demonstrated that it could pick up a radio message from the ground station in Fort Monmouth and later relay that message to the ground station in Salinas. Researchers also tested the communication volume that the satellite could handle at once. During the 14-minute window in which Courier 1B stayed within range of one of
28497-487: The two length scales are comparable, there may be resonances . Early radars used very long wavelengths that were larger than the targets and thus received a vague signal, whereas many modern systems use shorter wavelengths (a few centimetres or less) that can image objects as small as a loaf of bread. Short radio waves reflect from curves and corners in a way similar to glint from a rounded piece of glass. The most reflective targets for short wavelengths have 90° angles between
28674-472: The use of radar altimeters possible in certain cases. The radar signals that are reflected back towards the radar receiver are the desirable ones that make radar detection work. If the object is moving either toward or away from the transmitter, there will be a slight change in the frequency of the radio waves due to the Doppler effect . Radar receivers are usually, but not always, in the same location as
28851-575: The use of Congress be erected on the banks of the Delaware near Trenton , or of the Potomac , near Georgetown , provided a suitable district can be procured on one of the rivers as aforesaid, for a federal town". In Federalist No. 43 , published January 23, 1788, James Madison argued that the new federal government would need authority over a national capital to provide for its own maintenance and safety. The Pennsylvania Mutiny of 1783 emphasized
29028-442: The violence. Many stores and other buildings were burned, and rebuilding from the riots was not completed until the late 1990s. In 1973, Congress enacted the District of Columbia Home Rule Act providing for an elected mayor and 13-member council for the district. In 1975, Walter Washington became the district's first elected and first black mayor. Since the 1980s, the D.C. statehood movement has grown in prominence. In 2016,
29205-541: The width of the adjacent street plus 20 feet (6.1 m). Despite popular belief, no law has ever limited buildings to the height of the United States Capitol or the 555-foot (169 m) Washington Monument , which remains the district's tallest structure. City leaders have cited the height restriction as a primary reason that the district has limited affordable housing and its metro area has suburban sprawl and traffic problems. Washington, D.C., still has
29382-608: Was a 1938 Bell Lab unit on some United Air Lines aircraft. Aircraft can land in fog at airports equipped with radar-assisted ground-controlled approach systems in which the plane's position is observed on precision approach radar screens by operators who thereby give radio landing instructions to the pilot, maintaining the aircraft on a defined approach path to the runway. Military fighter aircraft are usually fitted with air-to-air targeting radars, to detect and target enemy aircraft. In addition, larger specialized military aircraft carry powerful airborne radars to observe air traffic over
29559-437: Was broadcast from the satellite to countries around the world, proving for the first time that orbiting satellites can relay voice and data signals over great distances. This achievement was followed up with the successful launch of TIROS-1 on April 1, 1960, as the world’s first full-scale weather satellite. The Television Infrared Observation Satellite (TIROS) program served as a joint government experiment between SCL, NASA ,
29736-856: Was changed to the U.S. Army Electronics Laboratories. Ultimately, the U.S. Army Electronics Laboratories was discontinued on June 1, 1965. The organization was then broken up into six separate Army laboratories: the Electronic Components Laboratory, the Communications/ADP Laboratory, the Atmospheric Sciences Laboratory , the Electronic Warfare Laboratory, the Avionics Laboratory, and the Combat Surveillance and Target Acquisition Laboratory. Around
29913-485: Was dropped and the Finance Department was added. As part of the Army reorganization in 1962, Congress eliminated the Technical Services and transferred the material development and procurement functions of the Signal Corps to the newly created Army Materiel Command (AMC). On August 1, 1962, AMC established one of its subordinate elements, the U.S. Army Electronics Command (ECOM), at Fort Monmouth to continue
30090-562: Was launched into orbit on March 17, 1958. The solar power devices developed by SCL enabled Vanguard I’s radio transmitters to operate for years, whereas a conventional battery would have only lasted several days. Due to the success of the solar cells, solar power quickly became the primary method of powering satellites and space probes following Vanguard I. SCL’s contribution to the Space Race continued with Project SCORE (Signal Communications via Orbiting Relay Equipment), which orchestrated
30267-462: Was most well-known for its role in the invention of radar . While the U.S. Navy and the Naval Research Laboratory were responsible for the initial development of radar in the 1920s, the Signal Corps significantly advanced its capabilities in the years leading up to World War II. Before 1930, the Ordnance Department was responsible for radar work on the U.S. Army side. Known as Project OKO 26242, “Investigation of Detection Devices Using Infra-Red Ray,”
30444-705: Was named Camp Coles in honor of Colonel Ray Howard Coles, the Executive Officer for the Chief Signal Officer of the American Expeditionary Forces in World War I . Field Laboratory Number Two served as a location where Signal Corps researchers worked on wire, direction-finding, sound-and-light, and meteorological projects. Situated in Camp Charles Wood near Eatontown, New Jersey , the field laboratory later became known as
30621-631: Was released at designated altitudes, through which they obtained new knowledge of high-altitude winds in the process. The focus on meteorological research and development persisted as WSSCA became the U.S. Army Signal Missile Support Agency in 1959. SMSA developed the Sonic Observation of Trajectory and Impact of Missiles (SOTIM) System, which provided acoustic information on missiles upon re-entry and impact. These stations were installed at 16 different points at White Sands Missile Range and were also equipped to measure wind speed, temperature, and humidity. SMSA also built meteorological rockets that could carry
30798-427: Was repeated several times before the War Department announced the accomplishment to the public on January 24. Project Diana represented the first demonstration of artificially created signals piercing the ionosphere and is often noted as the birth of the U.S. space program as well as that of radar astronomy . The resulting “Moonbounce” technique, now known as Earth-Moon-Earth (EME) communication , granted researchers
30975-413: Was responsible for providing communication-electronic, meteorologic, and other support to WSMR as well as conducting research and development in meteorology, electronic warfare, and missile vulnerability. At the time, the meteorological activities at WSMR were under the jurisdiction of the U.S. Army Electronics Research and Development Activity as well as the Atmospheric Sciences Office, an organization under
31152-748: Was sent to the U.S. in 1941 to advise on air defense after Japan's attack on Pearl Harbor . Alfred Lee Loomis organized the secret MIT Radiation Laboratory at Massachusetts Institute of Technology , Cambridge, Massachusetts which developed microwave radar technology in the years 1941–45. Later, in 1943, Page greatly improved radar with the monopulse technique that was used for many years in most radar applications. The war precipitated research to find better resolution, more portability, and more features for radar, including small, lightweight sets to equip night fighters ( aircraft interception radar ) and maritime patrol aircraft ( air-to-surface-vessel radar ), and complementary navigation systems like Oboe used by
31329-411: Was the first to use radio waves to detect "the presence of distant metallic objects". In 1904, he demonstrated the feasibility of detecting a ship in dense fog, but not its distance from the transmitter. He obtained a patent for his detection device in April 1904 and later a patent for a related amendment for estimating the distance to the ship. He also obtained a British patent on 23 September 1904 for
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