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Topic: Isotropic antenna

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	Isotropy - Wikipedia, the free encyclopedia
		Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented.
		Radio broadcasting: In radio, an isotropic antenna is an imaginary "device" used as a reference; an antenna that broadcasts power equally (calculated by the poynting vector) in all directions.
		An antenna's gain along its primary axis is usually reported in Decibels relative to an isotropic antenna, and is expressed as dBi or dB(i).
	en.wikipedia.org /wiki/Isotropic (195 words)

	Isotropic antenna - Wikipedia, the free encyclopedia
		An isotropic antenna is an ideal antenna that radiates power with unit gain uniformly in all directions and is often used to reference antenna gains in wireless systems.
		There is no actual physical isotropic antenna; a close approximation is a stack of two pairs of crossed dipole antennas driven in quadrature.
		The radiation pattern for the isotropic antenna is a sphere with the antenna at its center.
	en.wikipedia.org /wiki/Isotropic_antenna (129 words)

	Isotropic antenna -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-12)
		An isotropic antenna is an ideal (An electrical device that sends or receives radio or television signals) antenna that radiates power with unit gain uniformly in all directions and is often used to reference antenna gains in wireless systems.
		There is no actual physical (Click link for more info and facts about isotropic) isotropic antenna; a close approximation is a stack of two pairs of crossed (An aerial half a wavelength long consisting of two rods connected to a transmission line at the center) dipole antennas driven in quadrature.
		Antenna gains are often specified in dBi, or (A logarithmic unit of sound intensity; 10 times the logarithm of the ratio of the sound intensity to some reference intensity) decibels over (Click link for more info and facts about isotropic) isotropic.
	www.absoluteastronomy.com /encyclopedia/i/is/isotropic_antenna.htm (163 words)

	Antennas
		Antennas are also used in "receive mode" to collect radiation from "free space" and deliver the energy contained in the propagating wave to the feeder and receiver.
		The biconical antenna, and its derivatives, the broad-banded Yagi, the bow-tie antenna and the phantom conical antenna (which doesn't have a complete conical surface, but just conically disposed rod elements), is a good method of broad-banding a dipole type of antenna.
		In a reflector-aperture antenna fed from the front by a sub-reflector and/or a feed, the far field radiation pattern can be calculated from the Fourier Transform of the field distribution across the aperture, accounting as well for phase variations across the illuminated area.
	www.ee.surrey.ac.uk /Personal/D.Jefferies/antennas.html (9048 words)

	Omnidirectional isotropic antenna - Patent 5859615
		The antenna as claimed in claim 1 wherein the ratio of the length of the minor axis to the major axis is in the range of 1:1.0 to 1.0:0.25.
		The antenna as claimed in claim 1 wherein the antenna is impedance matched to the waveguide by tapering the stem of the dielectric element.
		Omnidirectional isotropic antennas are extremely important in transmitting and receiving electromagnetic radiation patterns where the direction is variable and it is undesirable to use pointing or detecting mechanisms.
	www.freepatentsonline.com /5859615.html (3038 words)

	Antenna Concepts (Site not responding. Last check: 2007-10-12)
		An antenna must be tuned to the same frequency band that the radio system to which it is connected operates in, otherwise reception and/or transmission will be impaired.
		The radiation or antenna pattern describes the relative strength of the radiated field in various directions from the antenna, at a fixed or constant distance.
		The radiation pattern in the region close to the antenna is not exactly the same as the pattern at large distances.
	radioproshop.com /antennaconcepts.htm (1877 words)

	Antennas
		antenna should not be confused with an isotropic antenna for while an isotropic antenna will radiate in all 3 dimensional directions an omnidirectional antenna may not radiate vertically (up or down).
		Selecting an antenna may be a complex task in attempting to balance the need to communicate to several stations in different directions without tall masts and within government power restrictions.
		A yagi antenna may be considered as a directional form of a dipole antenna and the comments on the dipole antenna are applicable.
	www.olotwireless.net /castella/Antennas.htm (1486 words)

	Isotropic antenna (Site not responding. Last check: 2007-10-12)
		There is no actual physical isotropic antenna; a close approximation is a stack of two pairs of crossed dipole antenna s driven in quadrature.
		Antenna gains are often specified in dBi, or decibel s over isotropic.
		Antenna Scatterers Analysis Program Free general purpose thin-wire antenna analysis software program for antenna design, modeling, and/or analysis.
	www.serebella.com /encyclopedia/article-Isotropic_antenna.html (404 words)

	Isotropic (Site not responding. Last check: 2007-10-12)
		An increase in average of mean isotropic ADC values of the patient group 2 is observed (P =.0085).
		In radio, an isotropic antenna is an imaginary "device", used as a reference.
		Decibels relative to an isotropic antenna are expressed as dBi or dB(i).
	www.wikiverse.org /isotropic (247 words)

	Professional Wireless Systems (Site not responding. Last check: 2007-10-12)
		The isotropic antenna is the theoretical perfect radiator, it radiates all frequencies in all directions with no losses.
		This antenna does not provide any rejection, but it is possible to use a single antenna for parts of both the VHF and UHF bands.
		This antenna is ideally suited to installations in which the range of frequencies in use is fairly small.
	www.professionalwireless.com /04_antenna.htm (507 words)

	Cisco - Cisco Aironet Antenna Reference Guide (Site not responding. Last check: 2007-10-12)
		An isotropic antenna is a theoretical antenna with a uniform three-dimensional radiation pattern (similar to a light bulb with no reflector).
		The dipole radiation pattern is 360 degrees in the horizontal plane and 75 degrees in the vertical plane (assuming the dipole antenna is standing vertically) and resembles a donut in shape.
		This mount permits the yagi antenna to be mounted to a flat surface or a mast, and then be adjusted in both horizontal and vertical angles.
	www.cisco.com /warp/public/cc/pd/witc/ao350ap/prodlit/agder_rg.htm (6565 words)

	Basic Antenna Theory and Transmission
		Antenna theory is a large subject, so this is just a brief introduction, highlighting some important antenna topics which are relevant to circuits on this site.
		The centre vertical line represents the length of the antenna, L in meters, R is the radius of the near field.
		It should be noted that this equation assumes 100% energy is transferred from the transmitter to the antenna, and that the antenna has unity gain (a dipole).
	www.mitedu.freeserve.co.uk /Theory/antenna.htm (816 words)

	Encyclopedia: Isotropic antenna (Site not responding. Last check: 2007-10-12)
		A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves.
		A dipole antenna is an antenna with two driven elements.
		Although it is widely used as a measure of the loudness of sound, the decibel (dB) is more generally a measure of the ratio between two quantities, and can be used to express a wide variety of measurements in acoustics and electronics.
	www.nationmaster.com /encyclopedia/Isotropic-antenna (308 words)

	isotropic radiator - a Whatis.com definition
		An isotropic radiator is a transducer that produces useful electromagnetic field output in all directions with equal intensity, and at 100-percent efficiency, in three-dimensional space.
		In wireless applications, an isotropic radiator can be approximated by constructing a single-turn square loop with a circumference of 1/2 wavelength, and then giving the loop a half-twist along an axis that lies in the plane of the loop.
		A dipole antenna, for example, has signal output and sensitivity approximately 2.15 decibels greater, in its favored directions, than the output and sensitivity of an isotropic antenna.
	whatis.techtarget.com /definition/0,,sid9_gci214570,00.html (199 words)

	TFCBooks -- Tesla Site Glossary
		Along with the energy lost or radiated from a radio antenna, a certain fraction of the energy is also returned during each radio-frequency cycle, meaning the radiation fields associated with a transmitter's antenna represent both energy storage and far-field radiation components.
		Not unlike the Hertz antenna, the Marconi antenna is intended as a source electromagnetic radiation in the form of space waves.
		When both transmitting and receiving antennas are on, or close to, the ground, and the distance between them becomes great, the direct and reflected components tend to cancel out, and the resulting field intensity is principally that of the surface wave.
	www.tfcbooks.com /mainpage/glossary.htm (12184 words)

	Antenna Angular Spectrum Calculator
		The spectrum is a result of constructive/destructive interference among the various antennas and depends sensitively on the physical arrangement of those antennas, the direction in which they are pointed, and their individual electromagnetic characteristics.
		An isotropic antenna has the same gain in every direction and is mostly useful for understanding interference patterns.
		A dipolar antenna requires specification of its orientation, which is the direction of the long axis of the antenna.
	www.xtrsystems.com /RA/cgi/antenna (944 words)

	Isotropic antenna (Site not responding. Last check: 2007-10-12)
		is no actual physical isotropic antenna; a approximation is a stack of two pairs crossed dipole antennas driven in quadrature.
		This is the power the strongest direction divided by the power would be transmitted by an isotropic antenna the same total power.
		Antenna has to be one of ZZ Tops, top five albums of all time and its one of my personal favorites.
	www.freeglossary.com /Isotropic_antenna (408 words)

	Cisco Aironet Antenna Reference Guide [Cisco Aironet Antennas and Accessories] - Cisco Systems
		This antenna reference guide is intended to provide information to assist in understanding the issues and concerns of antennas used with a Cisco® Aironet® wireless LAN system, or wireless bridge system.
		An antenna rating is typically to the gain of an isotropic or dipole antenna.
		Patch antennas are designed to mount flat against a wall or ceiling, and ceiling-mount antennas are equipped with a drop-ceiling cross-member attachment.
	www.cisco.com /en/US/products/hw/wireless/ps469/products_data_sheet09186a008008883b.html (5264 words)

	Erecting an Antenna
		If you do not need an antenna for over-the-air stations, there is no reason for you to read this section.
		There is a chance that the first antenna you install will not meet your expectations.
		Although the dollar cost of an antenna system is modest, a lot of your time might be required.
	www.hdtvprimer.com /ISSUES/erecting_antenna.html (340 words)

	How to Pick the Right Antenna (Site not responding. Last check: 2007-10-12)
		All RF (in relation to antenna gain) starts out as the power that would be put out by a perfect point in space that would radiate the signal in all directions and create a perfect sphere of energy and is called an isotropic radiator.
		Panel antennas also have smaller side lobes and wider main lobes (a lobe would be a high power area, or the peaks on the charts above) making them better at eliminating multi-path and easier to aim.
		It was on his crank up TV antenna tower and we were not able to point the antenna in the exact area that we thought the tower was (too far away to see).
	www.odessaoffice.com /wireless/antenna/how_to_pick_the_right_antenna.htm (2144 words)

	Marsspec
		The antenna (a single 15 element Yagi) was probably one of the smallest used anywhere to receive the signal, but relatively high signal-to-noise ratio was achieved by narrowing down the bandwidth to just over 0.01 Hz.
		In the analysis, an injected stable tone, loosely coupled to the antenna during the measurements, was used to determine and compensate for receiver phase and frequency drift.
		The 0 dB reference on the above plot is the level predicted for a 1.3 watt transmitter and isotropic antenna at a distance of 5.025 million km, corresponding to the MGS at the time of the measurements.
	ourworld.compuserve.com /homepages/demerson/marsspec.htm (1936 words)

	Antenna Link for More Info (Site not responding. Last check: 2007-10-12)
		This is the right way to explain antenna gain as a function of effective area, and I have run into engineers that don't get it.
		This is off topic, but an understanding of effective area can make understandable why, using parabolic antennas of fixed physical dimensions and distance, and ignoring attenuation by the atmosphere, the power transfer between the two antennas will increase as wavelength decreases.
		An isotropic radiator is a hypothetical source radiating power equally in all directions.
	www.kyes.com /antenna/formulas.html (284 words)

	Definition: antenna gain
		antenna gain: The ratio of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength at the same distance.
		Note 1: Antenna gain is usually expressed in dB.
		), when the reference antenna is a linear conductor, much shorter than one quarter of the wavelength, normal to the surface of a perfectly conducting plane which contains the given direction.
	www.atis.org /tg2k/_antenna_gain.html (207 words)

	Lecture 3, Earth Segment
		An Isotropic Antenna is a (theoretical) antenna that radiates energy uniformly in all directions.
		The relationship between the gain G of an antenna and its effective area (where l is the wavelength in metres) is:
		So, L, which is the ratio of the spreading area to the area of an isotropic antenna is the free-space attenuation between isotropic antennas and is often called the "path loss".
	www.satcom.co.uk /article.asp?article=5§ion=3 (371 words)

	decibels relative to isotropic radiator - a Whatis.com definition
		The expression dBi is used to define the gain of an antenna system relative to an isotropic radiator at
		The symbol is an abbreviation for "decibels relative to isotropic."
		A dipole antenna has a gain of 2.15 dBi.
	whatis.techtarget.com /definition/0,,sid9_gci214571,00.html (158 words)

	Antennas Direct \| Your HDTV Antenna Specialist
		Antennas Direct DB4 is featured in recent Tech Living article about HD Antennas.
		The XG91 from Antennas Direct sets the standard as the world’s most powerful long range UHF Style HDTV antenna...
		The new V4 VHF antenna meets the needs of those trying to get channels broadcast on the low VHF band like Chicago's WBBM...
	www.antennasdirect.com (102 words)

	Re: Isotropic Antenna (Site not responding. Last check: 2007-10-12)
		Not only that but any standing waves that develop on the antenna just slide off and pile up underneath it.
		Be sure to place a bucket under your antenna and empty it daily.
		That's why many people say they have a "hot antenna".
	www.midnightscience.com /_web/000009ac.htm (62 words)

	Welcome to CellPhoneSolutions.com
		If ordering a replacement OEM Antenna, make sure to specify the make and model of your phone / and whether you want the stubby or retractable model, in the "notes" section on the ordering form.
		Our special antennas and add-ons boost your signal, up to 300% enhanced quality, protect you from the dangerous radiation emitted from every cellular phone.
		This antenna is perfect for the car, home, or office.
	www.cellphonesolutions.com (325 words)

	Telecom Dictionary-I: inclination, interference, isotropic antenna, ISDN, ITU (Site not responding. Last check: 2007-10-12)
		Telecom Dictionary-I: inclination, interference, isotropic antenna, ISDN, ITU
		ISDN Digital Subscriber Line (IDSL) - This is a type of DSL service that provides up to 144-Kbps transfer rates in each direction (slower than ADSL) and can be used regardless of the distance the customer is from the telephone central office (unlike ADSL).
		Isotropic Antenna - This is a hypothetical one-directional point-source antenna that serves as a reference for the measurement of antenna gain for engineering calculations.
	www.satellite-tv-hq.com /telecom-glossary-i.htm (678 words)

Isotropic antenna (Site not responding. Last check: 2007-10-12)

Isotropic antenna

Isotropic antenna
article at Free Euro Online Encyclopedia

It uses material from the wikipedia article Isotropic antenna.

www.eurofreehost.com /is/Isotropic_antenna.html (145 words)

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Topic: Isotropic antenna

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