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Topic: Antenna noise temperature

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	tBLOG - juluganti
		The gain of an antenna is the ratio of the power radiated (or received) per unit solid angle by the antenna in a given direction to the power radiated (or received) per unit solid angle by an isotropic antenna fed with the same power.
		The noise figure is the ratio of the noise power at the output of a device to the noise power at the input to the device, where the input noise temperature is equal to the reference temperature (290 K).
		It is a measure of the noise power generated by a practical device, expressed as the equivalent temperature of a resistor which, when placed at the input of a perfect noise-free device, generates the same amount of output noise.
	swethaajs.tblog.com (5480 words)

	Amplifier noise temperatures (Site not responding. Last check: 2007-10-20)
		This noise temperature Tn is found by toggling a source with known on and off temperatures T, and measuring the two resulting levels of output power.
		Summary: The noise temperature Tn of the two amplifiers in cascade is the noise temperature of the first plus the noise temperature of the second divided by the gain of the first:
		Assuming the coax is more or less at room temperature 290 K, attach an infinitely long piece of the same type coax also at room temperature to the input of this `amplifier.' The output and input temperatures must both be 290 K since they are both infinite lines.
	www.mth.msu.edu /~maccluer/Lna/noisetemp.html (520 words)

	Noise temperature, Noise Figure and Noise Factor
		Noise temperature is measured in units called Kelvin (K) and these are like Celsius (C) temperature degrees but start at zero for absolute zero temperature so 0 K = -273 deg C 273 K = 0 deg C (ice melts) 290 K = 17 deg C (ambient temperature of a waveguide, for example)
		Antenna noise temperature is referenced to the flange specified by the manufacturer.
		The noise temperature of the cable after the LNA refers to the input of the cable.
	www.satsig.net /noise.htm (636 words)

	SM 5 BSZ - Preamplifier design.
		In the discussion of the noise contributions from the input circuit, represented by R1 in fig.1 the transistor is assumed to be neutralised.
		Noise temperature to add to antenna temperature due to losses in the input circuit of the preamplifier and influence of input losses on S/N ratio.
		The antenna temperature is assumed to be 190K and the transistor temperature is assumed to be 15K.
	www.nitehawk.com /sm5bsz/pcdsp/preamp.htm (2712 words)

	Experiment COLD: Experimental Technique
		The measured noise temperature of the northern sector of the RATAN-600 as a function of elevation angle is shown in Fig.
		The amount of noise from the antenna is determined by spillover (illumination by radiation from the ground through the error pattern of the mirrors).
		Figure 3.7 The increase in the temperature of the boiling nitrogen as measured by the iermocouple and the radiometer (from the emission of the cold load) during the increase in the pressure within the volume filled with liquid nitrogen.
	www.sao.ru /hq/CG/cold/part3.htm (2874 words)

	NX7U on AO-40...NEC-2 Analysis of BBQ Grid Dish
		It is common amongst professional antenna engineers to refer to the radiation pattern of the reflector feed alone as the "primary pattern", and to the pattern of the feed+reflector as the "secondary pattern".
		Note that for any axially (z-axis) symmetric pattern, the antenna noise temperature at elevation=0 degrees is (Tgnd+Tsky)/2, since exactly 1/2 of the antenna pattern strikes the warm earth, and 1/2 of the antenna pattern "sees" the cold sky.
		The noise temperature continues to decline slowly with increasing elevation, as the higher-level close-in sidelobes are pointed to cold sky.
	members.cox.net /nx7u/ao40/bbqdish/BBQGridNec.htm (1921 words)

	Noise Temperature and Noise Fighure (Site not responding. Last check: 2007-10-20)
		the two-port is ideally noise free) and have a noisy resistor conencted the input port.
		The IRE definition states that the noise temperature of a two port network is the noise temperature which assigned to the input port of a noise free equivalent of the network yields the saime available output noise power density as the actual network with noise free source.
		So, the equivalant Noise Temperatur is the temperture of a resistor connected to the receiver that creates just as much noise as the antenna does pointed in a specific direction.
	www.edaboard.com /ftopic48805.html (425 words)

	Antenna (biology)
		Antennae (singular antenna), are the paired appendages connecting to the first (and in crustaceans also to the second) segment of the head of the members of all subphyla of the arthropods except Chelicerata.
		Antennae are jointed, and in crustaceans branching, they generally extend forward of the animal and are known to be sensory organs, although the exact nature of what they sense and how they sense it is often not entirely clear.
		In insects olfactory receptors on the antennae express bind to odor molecules and pheromones.
	www.kiwipedia.com /antenna--biology-.html (169 words)

	Site noise vs. system noise figure
		Antenna noise figure Sometimes you will see the term antenna noise temperature used to describe the level of ambient site noise in which the antenna is placed.
		Now the resistor is contributing 0.055'V of noise, and the input noise at the receiver is 0.055'V. Because the two noise voltages are non-coherent, the total or resultant noise voltage at the input to the receiver is found from the root-sum-square (RSS) of the two voltages.
		If we substitute an antenna for the resistor the antenna will have the same effect on noise figure; that is, assuming that the antenna is placed in an environment where site noise is negligible.
	mrtmag.com /mag/radio_site_noise_vs (1577 words)

	Experiment COLD: Limiting Factors and Characteristics of the RATAN
		The noise from any one of these interference factors cannot, as a rule, be characterized by a single parameter; this type of noise requires many parameters to describe it, and has a complicated (and unstable!) correlation function (the correlation function for the white noise in the radiometer is, by nature, a
		Both experiment and the modern theory of the observation of signals against a background of noise suggest that the classical approach is to find the solution to the optimal filtering problem, where the frequency response curve of the receiver system is the complex conjugate of the signal spectrum.
		sr, the so-called "effective antenna temperature" of the load resistance would be exactly equal to the brightness temperature of the background, i.e., 2.7 K. When studying an object of finite extent, it is necessary to know the shape of the source as well as the complete antenna pattern, i.e.
	brown.nord.nw.ru /CG/cold/part4.htm (5518 words)

	strutscattering2
		The other is the increase in antenna noise temperature due to scattering of the radiation into the feeds from ambient surroundings.
		In some antennas such as the JCMT and Voyager spacecraft, the support structure is similar to those of optical telescopes, with the supports arranged as triangular frames.
		The maximum possible contribution to the antenna noise temperature by strut scattering is therefore ~5.5 K, though even with non-ideal structures we expect much less than this.
	www.cv.nrao.edu /alma/almaweb/www/memos/html-memos/alma195/memo195.html (2837 words)

	Care and Feeding of a SETI Dish
		The antenna used in our first Project Argus stations suffered from low illumination efficiency and relatively high noise temperature, due primarily to the simple cylindrical waveguide feedhorn employed.
		With a dish designed for optimum gain, the antenna noise temperature, dominated by Earth-seeing sidelobes, is about 50 K. The overall system noise temperature is thus 100 K, and sensitivity (given 10 Hz bin width and 10 second integration) is on the order of 1.3 E-22 W/m^2.
		This approach skews the antenna pattern slightly, but the result is easily measured by peaking the antenna on sun noise, and compensating aiming accordingly.
	www.setileague.org /hardware/feedchok.htm (1920 words)

	Callisto \| Products: Noise Measurement Equipment
		Precise noise measurement in RF circuits is a technique, which Callisto has mastered by necessity through our work on ultra low noise amplifiers and receivers.
		The noise level in the system produces bit errors when the test signal is recovered and demodulated.
		The test signal, together with the receive chain system noise and any operational signals received by the antenna, will then be amplified and down converted by the ground station receive chain (shown in blue in the diagram).
	www.callisto-space.com /product.3.html (482 words)

	Noise temperature, Noise Figure and Noise Factor
		Noise temperature is measured in units called Kelvin (K) and these are like Celsius (C) temperature degrees but start at zero for absolute zero temperature so
		Antenna noise temperature = 35 K (mainly ground noise - varies with elevation)
		Some examples of antenna noise temperature versus elevation angle are shown on page antnoise.htm
	www.sasltd.com /T/faq/noise.html (294 words)

	Journal of Electronic Defense: Use basic concepts to determine antenna noise temperature. (EW Design Engineers' ... (Site not responding. Last check: 2007-10-20)
		In most RF systems, external noise enters through the antenna and adds to internal noise generated by the low noise amplifier (LNA) and resistive losses from filters and couplers (Figure 1).
		The noise contributed by the antenna is generated by the sky, earth and antenna resistive loss.
		A common figure of merit for a receiving system is G/T, where G is the antenna gain and T is the noise temperature of the combined sources.
	highbeam.com /library/doc0.asp?docid=1G1:11839335&refid=ink_tptd_mag (202 words)

	Satellite antenna noise temperature and elevation angle
		Antenna Noise temp (C band) (K) 6m diameter antenna Model 8060 from ViaSat (formerly Scientific Atlanta) C + Ku bands
		Noise temp (C band) (K) Noise temp (Ku band) (K) 3.6m diameter antenna Model 8136 from ViaSat C + Ku bands (Offset geometry)
		Noise temp (C band) (K) Noise temp (Ku band) (K) Channelmaster series (In this table the elevation angle is in the columns)
	www.satsig.net /antnoise.htm (197 words)

	Antenna Hungária Rt. (Site not responding. Last check: 2007-10-20)
		a receiving antenna collects noise from radiating bodies falling within its radiation pattern; for an on-ground receiving antenna, this includes contributions from the sky and from the surroundings (the earth); the combined affect of these noise sources is modelled by an equivalent noise temperature for the antenna, which varies with elevation angle and antenna size
		the pointing direction of an antenna measured in the local horizontal plane in a clockwise direction from north; it is the horizontal co-ordinate that is used to align a satellite antenna
		It is most often used to describe the radiation pattern of satellite antennas; the intersection of a satellite beam with the earth's surface is referred to as the (beam's) footprint
	www.ahrt.hu /en/services/E998916A5C074250853222342FEB2CA5.php (1205 words)

	I.S.P.A.-Group > Telecommunications > Fly Away Station
		Different models of unique umbrella type antenna systems with metallic tricot mesh reflectors can provide transmission and reception of signals through geo-stationary satellites over the range of 4/6 GHz or 11/14 GHz.
		The antenna systems operate as a part of a mobile earth station or DSNG-terminal.
		Antenna Noise temperature at the feed output under clear sky conditions at an elevation of 10°, max
	www.ispa.tv /ifas.html (396 words)

	Ask Dr. SETI: Cooling Low Noise Amplifiers
		First off, all else being equal the total system noise temperature (in Kelvins, or degrees above absolute zero) must be reduced by a factor of four in order to double communications range.
		A good GaAs PHEMT preamp may have a 50K noise temp at room ambient temperature; frozen carbon dioxide (dry ice) cooling might lower preamp noise by perhaps 35%.
		But now the problem becomes the rest of the system -- antenna noise temperature might be another 50K or so, mostly dominated by sidelobes.
	www.setileague.org /askdr/cooling.htm (367 words)

	Satcom Online - For Satcom Resources (Site not responding. Last check: 2007-10-20)
		SATSOFT is used for communication satellite antenna design, analysis, and coverage planning.
		Input component noise and gain figures and calculate total system noise temperature and G/T values.
		Simply input three of the fields Antenna Diameter, Efficiency, Gain or Frequency and the other field will be calculated automatically for you.
	www.satcom.co.uk (357 words)

	Quiet Solution, LLC
		Headquartered in Silicon Valley California, Quiet Solution develops and manufactures the world’s leading high-tech products for soundproofing.Our technology reduces noise and vibration by converting kinetic energy into tiny amounts of intermolecular heat energy.
		Download Sound and Noise Generation, a practical guide for making anything quiet — homes, condos, schools, factories, cars, SUVs, trucks, boats, RVs, appliances, machinery.
		Identify noise source and specify the appropriate products for your project.
	www.quietsolution.com (234 words)

	[No title] (Site not responding. Last check: 2007-10-20)
		N + 10 dB We need to know the noise temperature of our receiver so that we can calculate N, the noise power (N = Pn).
		We need a method which reduces several sources to a single equivalent noise source at the receiver input.
		Satellites: antennas beaming towards earth (about 300 K): Making the LNA noise temperature much less gives diminishing returns.
	classweb.gmu.edu /jmontana/lecture04b.ppt (654 words)

	2.4 Offset Satellite Antenna (Site not responding. Last check: 2007-10-20)
		Some of the top 2.4 offset satellite antenna resources:
		3 port 2 rx and 1 tx, add 4.5 4 port 2 rx and 2 tx, add 9.9 18m diameter antenna...
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	www.satellitedish9.info /1/2.4-offset-satellite-antenna.html (327 words)

	Bargain Antennas (Site not responding. Last check: 2007-10-20)
		There are many different antenna types and suppliers.
		Buy cell phone antennas for Nokia, Motorola, Ericsson, and Samsung cellular phones.
		Retailer offers supplies to boost cell phone signal strength and reduce drop calls, including antennas, signal boosters, building repeaters, and system design.
	www.bargain-antenna-site.co.uk /rv+antenna.html (114 words)

	COURSE UNIT
		ANTENNAS Salvatore CAORSI (Lab, Y, 4W, 31P, Opt, Or, 8Cr) Introduction and fundamentals of e.m.
		Radiation from apertures: Kirchoff integral, equivalence principle, Shelkunoff method; near field-far field transformation; reflector antennas, paraboloidal reflectors, efficiency; horns and lens antennas, corrugated horns; aperture antenna synthesis.
		Non electrical quantities transducers: position: potentiometers, synchros, resolvers, pulse generators, incremental and absolute encoders; optical, induction, saturable reactance, Hall effect, magnetic resistance encoders; signals decoding electronics; mechanical features, environmental conditions, resolution and reliability; speed: dc, ac, pulse tachometers; temperature: thermocouples, IC transducers; pressure, force: piezoelectric and piezoresistive transducers.
	dibemail.dibe.unige.it /department/micro/ECTS/corsi.html (3843 words)

	Bargain Antennas (Site not responding. Last check: 2007-10-20)
		If you are looking for antennas, aerials or just good information about them, youve come to the right place.
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	www.discount-antennashop.co.uk /antenna+tv+greece.htm (148 words)

	[No title] (Site not responding. Last check: 2007-10-20)
		- physical and noise temperatures of front-end amplifiers,
		- high antenna temperature sensitivity, to the point of several mK,
		State of the art of the continuum radiometers is provided for using of modern technologies:
	www.sao.ru /hq/lrk/complex/complex1.html (300 words)

	Course Outline for ECE 697C (Site not responding. Last check: 2007-10-20)
		Thermal Noise (gaussian bandlimited noise, pdf, white noise)
		Noise Figure of Passive Networks (noise figure of couplers)
		Antenna Noise Temperature (G/T) Basic Practical Antennas (dipoles, loops)
	www.ecs.umass.edu /ece/ece697c/outline.html (113 words)

	DX-Köp, Practical Antenna Handbook (Site not responding. Last check: 2007-10-20)
		Chapter 22: Adjusting, Installing and Troubleshooting Antennas and Transmission Lines.
		Chapter 23: Antennas for Radio Direction Finding (RDF).
		Chapter 25: Mobile, Emergency, Portable and Marine Antennas.
	www.sdxf.org /dxkop/practical.html (82 words)

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