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Type 281 Radar
The Type 281 radar was a British naval early-warning radar developed during World War II. It replaced the Type 79 as the Royal Navy's main early-warning radar during the war. The prototype system was mounted on the light cruiser in October 1940. This radar used a frequency of 90 MHz, a beamwidth of 35°, and a wavelength of . It required separate transmitting and receiving antennas that were rotated by hand. For long-range warning the radar used a 15 microsecond pulse at a power level of 350 kW that gave a detection range up to for aircraft. For tracking surface targets it used a 2–3 microsecond pulse at 1 MW that gave a range up to . A second set was installed in January 1941 aboard the battleship and production began of another 57 sets with the first deliveries occurring the following month. This set also had a secondary aerial and surface gunnery capability and used a Precision Ranging Panel. The Type 281 ranging system allowed the user to select either a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early-warning Radar
An early-warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as ''early'' as possible before the intruder reaches its target, giving the air defences the maximum time in which to operate. This contrasts with systems used primarily for tracking or gun laying, which tend to offer shorter ranges but offer much higher accuracy. EW radars tend to share a number of design features that improve their performance in the role. For instance, EW radar typically operates at lower frequencies, and thus longer wavelengths, than other types. This greatly reduces their interaction with rain and snow in the air, and therefore improves their performance in the long-range role where their coverage area will often include precipitation. This also has the side-effect of lowering their optical resolution, but this is not important in this role. Likewise, EW radars often use much lower pulse repetition frequency to maximi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battleship
A battleship is a large armour, armored warship with a main artillery battery, battery consisting of large caliber guns. It dominated naval warfare in the late 19th and early 20th centuries. The term ''battleship'' came into use in the late 1880s to describe a type of ironclad warship,Stoll, J. ''Steaming in the Dark?'', Journal of Conflict Resolution Vol. 36 No. 2, June 1992. now referred to by historians as pre-dreadnought battleships. In 1906, the commissioning of into the United Kingdom's Royal Navy heralded a revolution in the field of battleship design. Subsequent battleship designs, influenced by HMS ''Dreadnought'', were referred to as "dreadnoughts", though the term eventually became obsolete as dreadnoughts became the only type of battleship in common use. Battleships were a symbol of naval dominance and national might, and for decades the battleship was a major factor in both diplomacy and military strategy.Sondhaus, L. ''Naval Warfare 1815–1914'', . A global arm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Radars
A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields. The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, deter or confront piracy, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of the navy also may incorporate nuclear deterrence by use of submarine-launched ballistic missiles. Naval operations can be broadly divided between riverine and littoral applications (brown-water navy), open-ocean applications (blu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II British Electronics
In its most general sense, the term "world" refers to the totality of entities, to the whole of reality or to everything that is. The nature of the world has been conceptualized differently in different fields. Some conceptions see the world as unique while others talk of a "plurality of worlds". Some treat the world as one simple object while others analyze the world as a complex made up of many parts. In ''scientific cosmology'' the world or universe is commonly defined as " e totality of all space and time; all that is, has been, and will be". '' Theories of modality'', on the other hand, talk of possible worlds as complete and consistent ways how things could have been. '' Phenomenology'', starting from the horizon of co-given objects present in the periphery of every experience, defines the world as the biggest horizon or the "horizon of all horizons". In ''philosophy of mind'', the world is commonly contrasted with the mind as that which is represented by the mind. ''T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type 960 Radar
Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Type (Unix), a command in POSIX shells that gives information about commands. * Type safety, the extent to which a programming language discourages or prevents type errors. * Type system, defines a programming language's response to data types. Mathematics * Type (model theory) * Type theory, basis for the study of type systems * Arity or type, the number of operands a function takes * Type, any proposition or set in the intuitionistic type theory * Type, of an entire function ** Exponential type Biology * Type (biology), which fixes a scientific name to a taxon * Dog type, categorization by use or function of domestic dogs Lettering * Type is a design concept for lettering used in typography which helped bring about modern textual prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plan Position Indicator
A plan position indicator (PPI) is a type of radar display that represents the radar antenna in the center of the display, with the distance from it and height above ground drawn as concentric circles. As the radar antenna rotates, a radial trace on the PPI sweeps in unison with it about the center point. It is the most common type of radar display. Description The radar antenna sends pulses while rotating 360 degrees around the radar site at a fixed elevation angle. It can then change angle or repeat at the same angle according to the need. Return echoes from targets are received by the antenna and processed by the receiver and the most direct display of those data is the PPI. The height of the echoes increases with the distance to the radar, as represented in the adjacent image. This change is not a straight line but a curve as the surface of the Earth is curved and ''sinks'' below the radar horizon. For fixed-site installations, north is usually represented at the top of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HACS
High Angle Control System (HACS) was a British anti-aircraft fire-control system employed by the Royal Navy from 1931 and used widely during World War II. HACS calculated the necessary deflection required to place an explosive shell in the location of a target flying at a known height, bearing and speed. Early history The HACS was first proposed in the 1920s and began to appear on Royal Navy (RN) ships in January 1930, when HACS I went to sea in . HACS I did not have any stabilization or power assist for director training. HACS III which appeared in 1935, had provision for stabilization, was hydraulically driven, featured much improved data transmission and it introduced the HACS III Table. The HACS III table (computer) had numerous improvements including raising maximum target speed to 350 knots, continuous automatic fuze prediction, improved geometry in the deflection Screen, and provisions for gyro inputs to provide stabilization of data received from the director. The HAC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of World War II British Naval Radar
This page is a List of World War II British naval radar. Nomenclature These sets were initially numbered as wireless telegraph (w/t) sets, but a distinguishing prefix of "2" was soon added. Metric sets were numbered in the 28x and 29x series. When centimetric sets arrived with the advent of the cavity magnetron, they were numbered by subtracting 10 from the metric type number they were based on (e.g. the metric Type 284 was replaced by the centimetric Type 274). This was not always possible however, as Types 271 - 274 were already in use for original centimetric sets, thus some metric sets in the Type 28x range had 20 subtracted (e.g. the metric Type 282 was replaced by the centimetric Type 262). Aerial outfits were given a three letter identifier that began with "A". Suffixing letters indicated the following; * B - conversion of sets with separate transmitting (Tx) and receiving (Rx) antennas to single antenna operation. * M, P, Q - major set modifications * R - addition of r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter '' lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Royal Navy During The Second World War A24895
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beamwidth
The beam diameter or beam width of an electromagnetic beam is the diameter along any specified line that is perpendicular to the beam axis and intersects it. Since beams typically do not have sharp edges, the diameter can be defined in many different ways. Five definitions of the beam width are in common use: D4σ, 10/90 or 20/80 knife-edge, 1/e2, FWHM, and D86. The beam width can be measured in units of length at a particular plane perpendicular to the beam axis, but it can also refer to the angular width, which is the angle subtended by the beam at the source. The angular width is also called the beam divergence. Beam diameter is usually used to characterize electromagnetic beams in the optical regime, and occasionally in the microwave regime, that is, cases in which the aperture from which the beam emerges is very large with respect to the wavelength. Beam diameter usually refers to a beam of circular cross section, but not necessarily so. A beam may, for example, have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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