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Topic: Super high frequency


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In the News (Tue 23 Apr 19)

  
  Encyclopedia: High frequency   (Site not responding. Last check: 2007-10-17)
High frequency (HF) radio frequencies are between 3 and 30 MHz.
The high frequency band is very popular with amateur radio operators, who can take advantage of direct, long-distance (often inter-continental) communications and the "thrill factor" resulting from making contacts in variable conditions.
This is due to the frequencies on which BPL operates (typically corresponding with the HF band) and the tendency for the BPL "signal" to leak from power lines.
www.nationmaster.com /encyclopedia/High-frequency   (1189 words)

  
 Analog Recording
To counteract this effect, the low frequency content of the record is deliberately reduced, and this low end rolloff has to be corrected by a bass boost in the playback system.
When the playback system reduces the high frequency content to its proper level, the noise in that range is reduced by the same amount.
Incidentally, since the record equalization increases the high frequency content of the signal, this clipping will happen to the highs first: that is why a cassette seems to lose its top end response when it is recorded "hot".
arts.ucsc.edu /EMS/Music/tech_background/TE-19/teces_19.html   (1375 words)

  
 Microwave - Wikipedia, the free encyclopedia
Microwaves have wavelengths approximately in the range of 30 cm (frequency = 1 GHz) to 1 mm (300 GHz).
The microwave range include ultra-high frequency (UHF) (0.3-3 GHz), super high frequency (SHF) (3-30 GHz), and extremely high frequency (EHF) (30-300 GHz) signals.
Plot of the zenith atmospheric transmission on the summit of Mauna Kea throughout the entire Gigahertz range of the electromagnetic spectrum at a precipitable water vapor level of 0.001 mm.
en.wikipedia.org /wiki/Super_high_frequency   (891 words)

  
 radio frequency - a Whatis.com definition - see also: RF
These frequencies cover a significant portion of the electromagnetic radiation spectrum, extending from nine kilohertz (9 kHz), the lowest allocated wireless communications frequency (it's within the range of human hearing), to thousands of gigahertz (GHz).
The frequency of an RF signal is inversely proportional to the wavelength of the EM field to which it corresponds.
As the frequency is increased beyond that of the RF spectrum, EM energy takes the form of infrared (IR), visible, ultraviolet (UV), X rays, and gamma rays.
searchnetworking.techtarget.com /sDefinition/0,,sid7_gci214263,00.html   (434 words)

  
 Microwave -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-17)
This page is about the (Energy that is radiated or transmitted in the form of rays or waves or particles) radiation; for the appliance, see (Kitchen appliance that cooks food by passing an electromagnetic wave through it; heat is produced by the absorption of microwave energy by the water molecules in the food) microwave oven.
However, the boundaries between far (The infrared part of the electromagnetic spectrum; electromagnetic wave frequencies below the visible range) infrared light, microwaves, and ultra-high-frequency (A communication system based on broadcasting electromagnetic waves) radio waves are fairly arbitrary and are used variously between different fields of study.
The existence of electromagnetic waves, of which microwaves are part of the higher frequency spectrum, was predicted by (Scottish physicist whose equations unified electricity and magnetism and who recognized the electromagnetic nature of light (1831-1879)) James Clerk Maxwell in 1864 from his famous (additional info and facts about Maxwell's equations) Maxwell's equations.
www.absoluteastronomy.com /encyclopedia/m/mi/microwave.htm   (1067 words)

  
 Pioneer ET-703 - www.pioneer.no
The ET-703 is a compression horn super high-frequency loudspeaker designed for a wide frequency range and high input power.
High input power is also achieved through the use of heat-resistant materials for the voice-coil bobbin and thermosetting resin.
With the highest resonance frequency set at 45kHz, the sound from the driver is free of coloration that can otherwise be caused by resonance.
www.pioneer.no /no/product_print.jsp?product_id=1482   (254 words)

  
 Radio frequency - Wikipedia, the free encyclopedia
Such frequencies account for the following parts of the spectrum shown in the table below.
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 SHF and EHF bands are often considered to be not part of the radio spectrum and form their own microwave spectrum.
en.wikipedia.org /wiki/High-frequency   (260 words)

  
 WCA Europe   (Site not responding. Last check: 2007-10-17)
Consequently, a section of the Radio Frequency (RF) spectrum between 27.5 and 29.5 GHz (billions of cycles per second) went virtually unused except in outer space.
It seems that using high frequency microwaves to transmit video was impractical.
Engineers had been focusing their attention lower in the RF spectrum, because they wanted lower frequency signals that (with enough power) could be sent long distances and penetrate buildings.
www.wcai.com /wcae/lmds1a.htm   (195 words)

  
 Different Transmission Techniques
FM stands for frequency modulation, and is another type of transmission, using a carrier but is slightly different.
The frequency is modulated and the amplitude of the wave remains constant.
At frequencies where we communicate using terrestial microwave (satellites, and ground dish-to-dish) extremely short wavelength frequencies are used.
www.roity.com /rc/transtech.html   (755 words)

  
 Frequency Spectrum (Police Traffic Radar Handbook)
The Federal Communications Commission (FCC) regulates frequency use by setting specifications for transmit frequency, power, bandwidth, modulation, and location, to name a few, and requires a license for many uses.
Frequency tolerance for Ka band radars typically ±100 MHz.
In the early days of radio it was easier to measure wavelength than frequency.
copradar.com /preview/xappA/xappA.html   (241 words)

  
 1959 History   (Site not responding. Last check: 2007-10-17)
High Power L-Band Rotating Sections for Multicoupler Systems The development of a high-power L-Band rotating section for multicoupler systems was completed in March.
High Power Pulse Switching Under a contract with Polytechnic Institute of Brooklyn, a two-megawatt all-magnetic modulator was developed.
AN/FRT-41 High Frequency Transmitter RADC developed the AN/FRT-41 high frequency transmitter using a klystron, i.e.
www.rl.af.mil /History/1950s/1959.html   (779 words)

  
 Radio frequency - Open Encyclopedia   (Site not responding. Last check: 2007-10-17)
The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency) spectrum, which is approximately 20–20,000 Hz.
Electrical connectors designed to work at radio frequencies are known as RF connectors.
RF is also the name of a standard audio/video connector, also called BNC (Bayonet Neill-Concelman).
open-encyclopedia.com /Radio_spectrum   (156 words)

  
 NTP 2 NAVAL TELECOMMUNICATIONS PROCEDURES NAVY SUPER HIGH FREQUENCY SATELLITE COMMUNICATIONS
Baseband -The band of frequencies occupied by the aggregate of the transmitted signals used to modulate a carrier, before they combine with a carrier in the modulation process.
Frequency Permutating -A process of pseudorandomly spreading out the eight tones of an uplink channel over the entire bandwidth of the associated satellite receiver.
Q Band -A band of frequencies extending from 36 to 46 GHz, corresponding to wavelengths of 0.834 to 0.652 cm.
www.fas.org /spp/military/docops/navy/ntp2/annex.htm   (2162 words)

  
 Wireless Technologies
They vary from the extremely low frequency (ELF) to tremendously high frequency (THF) and within this range are UHF (ultra-high frequency) and the VHF (very high frequency).
Microwave dishes and relay towers may be on the ground, however, they are usually situated atop high places, such as mountains or tall building, so that signals can be beamed over uneven terrain (ibid).
High frequency radio signals are transmitted from one terrestrial transmitter to another
cbdd.wsu.edu /kewlcontent/cdoutput/TR501/page16.htm   (971 words)

  
 SHF Military Communications Satellite
The system is used for high priority communication such as the exchange of wartime information between defense officials and battlefield commanders.
In response to a validated joint requirement, initial operating requirements were defined in 1972 for a shipboard Super High Frequency (SHF) satellite communications (SATCOM) terminal to provide high data rates for SURTASS T-AGOS platforms and jam-resistant voice and data circuits for major combatants beyond the line of sight (BLOS).
Since fielding of Extremely High Frequency (EHF) space segment and shipboard terminals for protected communications, Navy’s SHF SATCOM requirement has transitioned to unprotected interoperable high capacity voice, data, and video for combatants and flag capable ships, and reliable Joint/NATO-interoperable low probability-of-intercept (LPI), secure information exchange at medium to high data rates for fleet flag ships.
www.globalsecurity.org /space/systems/shf.htm   (645 words)

  
 Super-High-Frequency Systems
The super-high-frequency (SHF) band (3-30 GHz) is strictly for line-of-sight communications.
SHF satellite communications is a high-volume system that offers reliable tactical and strategic communications services to U.S. Navy elements ashore and afloat.
Navy Super High Frequency Satellite Communications, NTP 2, Section 1 (C), provides comprehensive coverage of the Navy SHF satellite system.
www.tpub.com /inch/6.htm   (343 words)

  
 Microwave
Microwaves, also known as Super High Frequency (SHF) signals, have wavelengths approximately in the range of 30 cm (1 GHz) to 1 mm (300 GHz).
A microwave oven uses a magnetron microwave generator to produce microwaves at a frequency of approximately 2.4 GHz for the purpose of cooking food.
NASA worked in the 1970s and early 1980s to research the possibilities of using Solar Power Satellite (SPS) systems with large solar arrays that would beam power down to the Earth's survace via microwaves.
www.brainyencyclopedia.com /encyclopedia/m/mi/microwave.html   (502 words)

  
 HingePin Integrative Learning Materials - Info Forum - Environmental Nutrition - Buck Levin
The microwaves that actually cook the food are classified as short wavelength, super high frequency (SHF) or extremely high frequency (EHF) radiation.
While polyploidy occurs frequently in plants, in humans it is relatively rare.
Beeswax, secreted from the glands on the underside of a bee’s abdomen; shellac, obtained from the lacca secretion of the lac beetle native to Pakistan and India; carnauba wax, obtained from the carnauba palm tree; and other wood rosins are also used as sources of fruit wax.
www.hingepin.com /infoforum.html   (2244 words)

  
 Freeware Download: Snaps
This allows you to hear the super high frequency content in your music and work with it.
DeSnap eliminates unwanted super loud high frequency clicks (snaps) that so often plague digital music, without sacrificing any brilliance.
These simple utilities are indispensable if you are in the habit of pushing your music for the best possible ultra high frequency content.
www.dirfile.com /freeware/snaps.htm   (166 words)

  
 Defense Tech: JIMMY CARTER: SUPER SPY?
Or, as the article says, various radio buoy transmitters and other means could be used to continually relay intercepts on to the NSA for detailed analysis.
Spread-spectrum or frequency agile, super high frequency (SHF) or extremely high frequency (EHF) transmitters, with very low probability of interception, mounted on low-observable buoys, constantly "talking" to U.S. spy satellites, are surely within current technical means if budgeting were available.
These transmitters could be powered for lengthy periods using the latest generation of fuel cell or semi fuel cell technology, some types of which are open to the sea and in fact use naturally circulating seawater as their electrolyte.
www.defensetech.org /archives/001397.html   (936 words)

  
 What is RF? - A Word Definition From the Webopedia Computer Dictionary
Short for radio frequency, any frequency within the electromagnetic spectrum associated with radio wave propagation.
Super high frequency (SHF) -- 3GHz - 30 GHz
Radio frequency is also abbreviated as rf or r.f.
www.webopedia.com /TERM/R/RF.html   (373 words)

  
 Satellite communications on-the-move
Directional antennas are needed at higher frequencies to overcome signal loss during propagation and to support higher data rates than can be supported at ultra-high frequency.
One of the consequences of using a directional antenna is that most objects (trees, buildings) coming between the antenna and the satellite will interfere with signal reception to the ground terminal.
The frequency and duration of good and poor reception will depend on the moving vehicle’s surroundings.
www.gordon.army.mil /ac/sumr01/satmove.htm   (1108 words)

  
 dvcointro
The ever-increasing demand for larger bandwidth in the wired and wireless communication markets is pushing integrated circuits to higher operation frequencies.
Since silicon suffers from larger parasitic elements both in active and passive devices, new circuit techniques and design methodologies are needed at such high frequencies.
LC VCO’s offer better phase noise performance, but it becomes more difficult to achieve all the desired VCO specifications simultaneously as the operation frequency approaches the self-resonance frequency of on-chip inductors and the cutoff frequency of transistors.
www.chic.caltech.edu /Reseach/dvcointro.htm   (518 words)

  
 SIGNAL Magazine
DVB operates over military super high frequency or extremely high frequency channels as well as over high-capacity commercial Ku- or Ka-band transponders, enabling the use of smaller and lighter receive dishes.
Among other strengths, the COFDM intrinsic resilience during multipath propagation allows the building of networks of scattered transmitters that operate on the same frequency channel and are slaved to a common global positioning system reference.
Small ultrahigh frequency (UHF) omnidirectional or low-gain antennas can be used on both transmit and receive sides of the link.
www.afcea.org /signal/articles/anmviewer.asp?a=440&print=yes   (1618 words)

  
 frequency_allocation.htm
Be aware having the right frequency may not be enough in tuning to a certain frequency.
Frequency Services 010 kHz 150 kHz Military/government, submarine communications 150 kHz 535 kHz Longwave band, beacons, foreign broadcast, maritime 520 kHz 1.7 MHz Standard AM radio dial MHz 030 MHz 160 -10 meter band: Shortwave/High Frequency band, broadcasting, two-way government, military and commercial communications, amateur radio, CB radio shortwave - approx.
are received better during night, while higher frequencies are received better during the day.
mywebpages.comcast.net /sidearm5/frequency_allocation.htm   (237 words)

  
 frequency bands
Because the complete radio spectrum is so broad it is considered to be divided up into bands, ranging from extremely low frequency (longest wavelengths) to extremely high frequency (shortest wavelengths).
Only a small part of this spectrum, from about one GHz to a few tens of GHz, is used for practical radio communications.
The band letters originate from World War II when reference to which frequency bands were being used needed to be kept secret.
www.daviddarling.info /encyclopedia/F/frequency_bands.html   (238 words)

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