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Topic: Extremely high frequency

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Ultra low frequency

Super high frequency

Very low frequency

Radio spectrum

Low frequency

Super low frequency

Microwave

Medium frequency

Very high frequency

Ultra high frequency

Shortwave

Electromagnetic spectrum

Longwave

Radio

Radio astronomy

	Extremely high frequency - Wikipedia, the free encyclopedia
		Extremely high frequency is the highest radio frequency band.
		EHF runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low (or far) infrared light.
		Radio signals in this band are extremely prone to atmospheric attenuation, making them of very little use over long distances.
	en.wikipedia.org /wiki/Extremely_high_frequency (173 words)

	Ultra high frequency - Wikipedia, the free encyclopedia
		Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz (Wavelength 1 meter) and 3.0 GHz (Wavelength 10 centimetres).
		Waves whose frequency is above the UHF band fall into the microwave or higher bands, while lower frequency signals fall into the VHF or lower bands.
		Modern mobile phones also transmit and receive within the UHF spectrum, and UHF is widely used for two-way radio communication (usually using narrowband frequency modulation, but digital services are on the rise) by both public service agencies and the general public.
	en.wikipedia.org /wiki/Ultra_high_frequency (963 words)

	Navy frequency band use
		Frequencies in the lower portion of the mf band (300 to 500 kilohertz) are used primarily for ground-wave transmission for moderately long distances over water and for moderate to short distances over land.
		In spite of the difficulties we encounter with hf propagation, the economic and technical advantages of using high frequencies have led to rapid expansion of the use of the hf band.
		Frequencies at the lower end of this band are capable of overcoming the shielding effects of hills and structures to some degree; but as the frequency is increased, the problem becomes more pronounced.
	www.tpub.com /neets/book17/73b.htm (2008 words)

	[No title] (Site not responding. Last check: 2007-10-08)
		Frequency is expressed in Hertz (Hz); a frequency of 1 Hz means that there is 1 cycle or oscillation per second.
		SHF refers to Radio Frequencies (RF) in the range of 3 GHz to 30 GHz (or as wavelenghts in the range of 10 cm to 1 cm) is known as the microwave band.
		UHF refers to Radio Frequencies (RF) in the range of 300 MHz to 3000 MHz (or as wavelenghts in the range of 100 cm to 10 cm) This band is used for mobile services, television, and non-communications services such as radar, space research, radio astronomy, and telemetry.
	home.wanadoo.nl /paulschils/03.00.html (706 words)

	Glossary : E
		Frequency band in the range of 30 - 300 GHz, corresponding to wavelength from 10 mm - 1 mm.
		EHF band is affected by atmospheric attenuation, caused by rain.
		Frequency band in the range of 3 - 30 Hz, corresponding to wavelength from 100,000 km to 10,000 km.
	www.conniq.com /Glossary_E.htm (569 words)

	Electronics:Frequency Spectrum - Wikibooks
		Frequency is the number of waves that pass by in a second.
		Shortwave radio operates between the frequencies of 3000 kHz and 30 MHz (30,000 kHz) and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than those commonly in use at that time.
		Unlike HF frequencies, the ionosphere does not usually reflect VHF radio and thus transmissions are restricted to the local area (and can't interfere with transmissions thousands of kilometres away) It is also less affected by atmospheric noise and interference from electrical equipment than low frequencies.
	en.wikibooks.org /wiki/Electronics:Frequency_Spectrum (8276 words)

	TFCBooks -- Tesla Site Glossary
		Extremely High Frequency (EHF) The portion of the electromagnetic spectrum between 30 GHz and 300 GHz.
		High Frequency (HF) The portion of the electromagnetic spectrum between 3000 kHz and 30,000 kHz.
		An LC circuit exhibits resonance at a specific frequency which is determined by the value of the inductor and the capacitor.
	www.tfcbooks.com /mainpage/glossary.htm (12184 words)

	Extremely low frequency
		Extremely low frequency or ELF refers to the band of radio frequencies from 3 to 300Hz.
		Despite the extremely high electrical conductivity of salt water, the water's density shields submarines from most electromagnetic communications.
		One of the difficulties posed when broadcasting in the ELF frequency range is antenna size.
	www.brainyencyclopedia.com /encyclopedia/e/ex/extremely_low_frequency.html (305 words)

	EMR Policy Institute FAQ - Question Two
		Microwaves occupy the ultra, super, and extremely high frequency bands; radar is a part of the microwave frequencies.
		Radio waves couple with each other as well as with other frequencies, and in some circumstances (like the presence of metallic objects) can create what are called standing waves or “hot spots”, meaning that they do not radiate into space, but remain within a set area at high intensities.
		There is some indication that certain FM frequencies may create standing waves in the brain that the body cannot dissipate.
	www.emrpolicy.org /faq/two.htm (407 words)

	Radio frequency - Wikipedia, the free encyclopedia
		Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna.
		Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque to higher frequencies of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.
		The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency) spectrum, which is approximately 20–20,000 Hz.
	en.wikipedia.org /wiki/Radio_frequency (210 words)

	Extremely High Frequency Electromagnetic Radiation in the Treatment of Depression. (Site not responding. Last check: 2007-10-08)
		Extremely High Frequency Electromagnetic Radiation in the Treatment of Depression.
		If you are using frequencies similar to that of the human body (i.e., 3.4 Hz to 5.2 Hz), then I see no cause for concern.
		Although, if you are using higher frequencies you are putting the body into an unnatural state of imbalance.
	infoventures.com /emf/currlit/bu12918.html (232 words)

	Extremely high frequency -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-08)
		Extremely high frequency is the highest (An electromagnetic wave frequency between audio and infrared) radio frequency (Something elongated that is worn around the body or one of the limbs) band.
		This band has a (The distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave) wavelength of one to ten (A metric unit of length equal to one thousandth of a meter) millimetres, giving it the name millimeter band.
		In the USA, the band 38.6 - 40.0 GHz is used for licensed high-speed microwave data links, and the 60 GHz band can be used for unlicensed short range (1.7 km) data links with data throughputs up to 2.5 Gbit/s (gigabits per second).
	www.absoluteastronomy.com /encyclopedia/e/ex/extremely_high_frequency.htm (154 words)

	Homeopathic and herbal remedies - Articles
		Weak extremely high frequency microwaves affect pollen-tube emergence and growth in kiwifruit: pollen grain irradiation and water-mediated effects.
		OBJECTIVE: This study was designed to evaluate the effects of weak-intensity extremely high frequency (EHF) microwaves in a model system-the plant organism pollen grain-lacking the placebo effect, available in large populations, to ensure accurate statistical analysis, and whose sensitivity is closely relevant to animal and human biology.
		It produces weak intensity EHF radiations (40-78 GHz), either continuous wave (cw) or modulated, at a 10 Hz-frequency, with infrared (IR) carried to 635-950 nm, and with an impedance (IPD) of 10(-21) W/Hz cm(2) and a power supply from 0 to 20 mW.
	www.web-outpatients.com /Articles.asp?Article_Id=50 (411 words)

	Viewzone// HAARP: Weapons of Total Distruction?
		For this reason, high frequency waves are said to propagate along the "line of sight." If you own a satellite television dish, you know that it is important for your antenna to be pointed in the direction of the satellite.
		A frequency of 15,000,000 (or 15 million hertz) means that the electrical energy is changing from positive to negative at the rate of 15-million times a second.
		To determine the "length" of this frequency, or "wavelength," we simply divide the velocity of light, 300,000,000 meters per second, by the frequency, say 15,000,000 cycles per second, to arrive at a distance in meters.
	www.viewzone.com /haarp11.html (928 words)

	NAVY SATCOM PMW176 FLEET WEB SITE: Products (Site not responding. Last check: 2007-10-08)
		To achieve this goal, the division is executing a two step approach by developing and fielding the Navy's Advanced EHF (Extremely High Frequency) Multiband Terminal (NMT) and initiating the concept development of a Transformation Communications (TC) terminal.
		The Super High Frequency (SHF) / Commercial Satellite Communications Division (PMW 176-4) is responsible for procuring, fielding, and sustaining SATCOM terminal systems to provide duplex wideband communications services to the Fleet.
		The Extremely High Frequency / Global Broadcast Service Division(GBS) (PMW 176-5) is responsible for procuring, fielding, and sustaining SATCOM terminal systems to provide protected and wideband broadcast communications services to the Fleet.
	enterprise.spawar.navy.mil /pmw176/products.htm (304 words)

	PBS: Tesla - Master of Lightning: High Frequency
		He knew that higher frequencies would have many technical advantages: lamps could glow brighter, energy could be transmitted more efficiently, and this would all be less dangerous because the energy could pass harmlessly across the body.
		Tesla began his high frequency investigations by building rotary AC generators that could run at higher speeds; but as he approached twenty thousand cycles per second, the machines began to fly apart, leaving him far short of his goal.
		In addition to high frequencies, the coil could also generate extremely high voltages.
	www.pbs.org /tesla/ll/ll_hifreq.html (382 words)

	Milstar 3 Advanced Extremely High Frequency (AEHF) Military Communications Satellite
		Advanced EHF is to consist of four cross-linked satellites covering the globe from 65 degrees north to 65 degrees south, providing 10 times the data rate available through MILSTAR.
		The Advanced EHF program was restructured, and the schedule accelerated, in response to the April 1999 incident in which a MILSTAR satellite was launched into an incorrect orbit.
		Option 4 (Accelerated Advanced EHF) is similar to Option 3, except that it accelerates development of the Advanced EHF satellite, achieving a first launch in FY 2000 and a four-satellite constellation in FY 2003.
	www.fas.org /spp/military/program/com/milstar3.htm (1747 words)

	Milstar 3 Advanced Extremely High Frequency (AEHF) Military Communications Satellite
		Option 1 (Milstar 2/Advanced EHF) would retain four Milstar 2 satellites, with a first launch in FY 1999 (as in the FY93 program), but it would eliminate the fifth Milstar 2 satellite (planned for delivery as a spare satellite in FY 2003) as well as subsequent Milstar-2 satellites.
		The first Advanced EHF satellite would be launched in FY 2003, with a four-satellite constellation in place in FY 2006.
		The group concluded that a reasonable objective would be to transition to a lighter, advanced EHF satellite that could be boosted into orbit by a medium-launch vehicle (MLV).
	www.globalsecurity.org /space/systems/milstar3.htm (2111 words)

	Online Dictionary for French English, Spanish English, Italian English, and more.
		The number of occurrences within a given time period (usually&service=&searchtype=stemmed&service=english2english">usually 1 second&service=&searchtype=stemmed&service=english2english">second); "the frequency of modulation was 40 cycles per second"; SYN: frequence.
		A distribution of observed frequencies of occurrence of the values of a variable.
		A response depicting the output-to-input ratio of a transducer as a function of frequency.
	www.ultralingua.net /?service=ee&text=frequency (221 words)

	Optical sensors - DirectIndustry.com (Site not responding. Last check: 2007-10-08)
		The MTI-2000 Fotonic Sensor is a high-resoulution fiber optic based vibration/displacement sensor with extremely high frequency response.
		The distance between the sender and receiver is determined by the shape of the housing and is referred to as the fork width.
		The emitted light, in the form of a precisely concentrated beam, and the high detection accuracy mean that even minute differences in light attenuation can be detected.
	directindustry.co.uk /search/optical-sensors.html (247 words)

	BASIC Publications
		In turn, each pair of shipboard receivers and transmitters for these frequency categories have corresponding facilities on shore, on aircraft, or on satellites for the relaying of messages to and from command headquarters to submarines.
		In addition to carrying launch orders, VLF-LF frequencies can also be used to tell SSBN crews to stand-down their operational readiness if a crisis abates, or to surface and receive more discriminating orders via higher frequencies that allow voice or data two-way communications.
		For both UHF and EHF frequencies, the NESP constitutes the primary means of STRATCOM-to-Trident voice and data communications for SSBN operations.
	www.basicint.org /pubs/Research/1999-Y2Kpart3.htm (4497 words)

	MRB: HIGH FREQUENCY (Site not responding. Last check: 2007-10-08)
		H IGH FREQUENCY A CTIVE A URORAL R ESEARCH P ROGRAM September 11, 2001 We are united We are resolved We...
		pipeline currents can reach hundreds of amps, HF (high frequency) radio propagation may be impossible in many areas for one to two days, satellite navigation may be degraded for days...
		Frequency of operation within the HF range The high frequency band is very popular with amateur radio operators, who can take advantage of direct, long-distance (often inter-continental) communications...
	www.medical-research-books.com /mrb-books-reviewed/B00020H3K8.html (457 words)

	Space Technology - Advanced EHF Military Communications Satellite (Site not responding. Last check: 2007-10-08)
		The Advanced EHF Programme is the follow-on to the DOD’s Milstar highly secure communication satellite programme, which currently has two Milstar I spacecraft in orbit.
		The estimated contract value of the Advanced EHF programme is $2.5 billion.
		To accomplish this, Advanced EHF adds new higher data rate modes to the low data rate and medium data rate modes of Milstar II satellites.
	www.space-technology.com /projects/ehf (696 words)

	Communications Today: Air Force Awards Lockheed Martin, TRW $2.7 Billion Contract - Advanced Extremely High Frequency ...
		The Advanced EHF Program is the next generation of global, highly secure, survivable communications system for all services of the Department of Defense.
		The Advanced EHF system is expected to deliver the coverage, capacity, connectivity and flexibility needed to provide unprecedented levels of assured communications interoperability for the U.S. Armed Forces, Harris said.
		The Advanced EHF constellation will offer secure data throughput capability and coverage flexibility to regional and global military operations and will also be backward compatible with the Milstar system.
	www.findarticles.com /p/articles/mi_m0BMD/is_218_7/ai_80202092 (522 words)

	NAVAL SPACE COMMAND (NAVSPACE) (Site not responding. Last check: 2007-10-08)
		Naval Space Command also manages a new generation of Ultra-High Frequency communications satellites now being launched to replace Fleet Satellite and Leased Satellite systems, which are nearing the end of their operational lives.
		The Ultra-High Frequency Follow-On spacecraft are designed for a 14-year lifetime and will be compatible with ground-based and sea-based communications terminals already in service.
		The Extremely-High Frequency packages on the Ultra-High Frequency Follow-On-4 and subsequent spacecraft in the series constitute an additional 11 channels distributed between an Earth coverage beam and a steerable 5-degree spot beam.
	www.au.af.mil /au/awc/awcgate/usspc-fs/navspace.htm (1262 words)

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