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Topic: Radio frequency


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  Radio - Wikipedia, the free encyclopedia
Radio waves are a form of electromagnetic radiation, created whenever a charged object (in normal radio transmission, an electron) accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum.
Although the word 'radio' is used to describe this phenomenon, the transmissions which we know as television, radio, radar, and cell phone are all classed as radio frequency emissions.
Radio remote control: Use of radio waves to transmit control data to a remote object as in some early forms of guided missile, some early TV remotes and a range of model boats, cars and aeroplanes.
en.wikipedia.org /wiki/Radio   (4650 words)

  
 Radio frequency - Wikipedia, the free encyclopedia
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.
Radio and light waves conversion: frequency to wavelength and vice versa
en.wikipedia.org /wiki/Radio_frequency   (356 words)

  
 radio frequency - a Whatis.com definition - see also: RF
Radio frequency (abbreviated RF, rf, or r.f.) is a term that refers to alternating current (AC) having characteristics such that, if the current is input to an antenna, an
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.
searchnetworking.techtarget.com /sDefinition/0,,sid7_gci214263,00.html   (442 words)

  
 Delivery of Internet services using HF Short Wave on electricity power lines. :: HamRadioIndia
Radio Amateurs will be the most affected radio user group because amateur radio stations are located in cities and towns where BPL proposes to operate using amateur radio frequencies between 1.7 to 30 MHz.
Amateur radio operators can not continue to operate their HF equipment if the power line outside their house is generating radio signals that block or disrupt radio frequencies inside the amateur radio bands.
Amateur radio is the biggest numerical user of short wave radio frequencies and its use by the citizens of Australia is poised to explode with the new beginner amateur radio license.
www.hamradioindia.org /news/news.php?news_id=104   (10351 words)

  
 Howstuffworks "How Radio Works"
Even though radio waves are invisible and completely undetectable to humans, they have totally changed society.
Whether we are talking about a cell phone, a baby monitor, a cordless phone or any one of the thousands of other wireless technologies, all of them use radio waves to communicate.
Things like communication and navigation satellites would be impossible without radio waves, as would modern aviation -- an airplane depends on a dozen different radio systems.
electronics.howstuffworks.com /radio.htm   (256 words)

  
 UK Radio Frequency Bands
Even having a private frequency stored in a receiver's memory channel is considered to be proof of intercepting messages that are not intended for you.
Personally, I've been fascinated by the magic of radio all of my life, fiddling around with radios since primary school, and over the years having read a fair bit about communication systems and the radio spectrum, I've now got a lot of radio information rattling around in my head.
The frequencies were 1538 kHz (normal pattern), then 1546, 1554, 1562, 1570, 1578, 1586, 1594, 1602." 1967, 30th Sept : BBC Radio 1 launched, and BBC Light (29.jul.1945), Third (sept 1946) and Home (sept 1939) are reorganised as Radios 2,3 & 4 (timeline) Light Prog was Forces Prog (1940) renamed for peacetime.
ukspec.tripod.com /spectrum.html   (8683 words)

  
 EPIC RFID Privacy Page
Frequent shopper cards link consumers to their purchases, but this limited information gives retailers only a narrow view of a consumers' in-store purchasing trends.
Students at Johns Hopkins University have discovered serious security flaws in the Radio Frequency Identification (RFID) chips which are used to protect cars from theft and prevent fraudulent use of Speedpass keys.
In testimony to the Federal Trade Commission on radio frequency identification technologies, EPIC called for the adoption of strong Privacy Guidelines for RFID Technology to protect consumers against potential abuses of the tracking technology.
www.epic.org /privacy/rfid   (5099 words)

  
 OET -- RF Safety FAQ's
The frequency of an RF signal is usually expressed in terms of a unit called the "hertz" (abbreviated "Hz").
Radio and television broadcasting, cellular telephones, personal communications services (PCS), pagers, cordless telephones, business radio, radio communications for police and fire departments, amateur radio, microwave point-to-point links and satellite communications are just a few of the many telecommunications applications of RF energy.
Since energy at some frequencies is absorbed by the human body more readily than energy at other frequencies, the frequency of the transmitted signal as well as its intensity is important.
www.fcc.gov /oet/rfsafety/rf-faqs.html   (8822 words)

  
 Radio frequency - Facts from the Encyclopedia - Yahoo! Education   (Site not responding. Last check: 2007-10-22)
Radio waves are identified by their frequencies, expressed in kilohertz (kHz), i.e., thousands of cycles per second, in megahertz (MHz), i.e., millions of cycles per second, or in gigahertz, i.e., billions of cycles per seconds.
Frequency modulation (FM) broadcast frequencies range from 88 MHz to 108 MHz.
A range, or band, of radio frequencies is regularly assigned to a broadcasting station or service by the nation in which it operates.
messenger.yahooligans.com /reference/encyclopedia/entry/radiofre   (208 words)

  
 Office of Radio Frequency Management
Radio signals are used for weather radar, radiosondes (one type of meteorological aid), weather satellites, wind profiling, and many other methods of gathering weather related information.
This page is here to provide information on the meteorological use of radio, on the present and potential impact on weather forecasting of some of the things that are happening today in the field of radio.
Upon approval on a frequency assignment by the FAS, NTIA issues a radio frequency authorization for that assignment and the assignment is recorded in the NTIA Government Master File (GMF) of Frequency Assignments.
www.orfm.noaa.gov   (826 words)

  
 Robert Schweitzer's testimony on radio frequency weapons.   (Site not responding. Last check: 2007-10-22)
In its 1994 meeting in Bordeaux, France, the Russians laid out fruits of their own work up until then, which included a very detailed description of a whole series of radio frequency weapons and papers that gave the strategy, doctrine, tactics and techniques as to how they would be used.
General Schweitzer, I take it that RF (radio frequency) devises [sic] are not new technology and the use of radio frequency is not something that we have just recently discovered.
But, what makes it unique I suppose, today is that the type of radio frequency weaponry that we can use applied to modern technology (i.e., computer chips) creates a much more intense and difficult situation for us to contemplate.
www.soci.niu.edu /~crypt/other/schweit.htm   (2794 words)

  
 OET -- Radio Frequency Safety
The FCC is required by the National Environmental Policy Act of 1969 to evaluate the effect of emissions from FCC-regulated transmitters on the quality of the human environment.
This is an informative bulletin written as a result of increasing interest and concern of the public with respect to this issue.
The expanding use of radio frequency technology has resulted in speculation concerning the alleged "electromagnetic pollution" of the environment and the potential dangers of exposure to non-ionizing radiation.
www.fcc.gov /oet/rfsafety   (664 words)

  
 Radio frequency Info - Encyclopedia WikiWhat.com   (Site not responding. Last check: 2007-10-22)
Radio frequency, or RF, is a carrier, or alternating current with or without a signal, at a frequency that can radiate, or propagate, if not shielded.
Note: 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 freqency ranges.
Analog signals that are not RF include IF (intermediate frequency) and AF (audio frequency, 20-20000 Hz).
www.wikiwhat.com /encyclopedia/r/ra/radio_frequency.html   (192 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.
Radio frequency is also abbreviated as rf or r.f.
The construction of a facility and silent sources of RF interference impact the propagation of radio waves, often in odd ways.
www.webopedia.com /TERM/R/RF.html   (375 words)

  
 Radio Free Europe on Encyclopedia.com   (Site not responding. Last check: 2007-10-22)
RADIO FREQUENCY [radio frequency] range of electromagnetic waves with a frequency or wavelength suitable for utilization in radio communication.
Radio Free Europe's impact on the Kremlin in the Hungarian crisis of 1956: three hypotheses.(introduction in French)
Sending cross-border static: on the fate of Radio Free Europe and the influence of international broadcasting.
encyclopedia.infonautics.com /html/r1/radiofre.asp   (1030 words)

  
 Wired News: Radio ID Tags: Beyond Bar Codes
Radio frequency identification (RFID) tags, which consist of silicon chips and an antenna that can transmit data to a wireless receiver, could one day be used to track everything from soda cans to cereal boxes.
Radio ID tags can be installed in clothing labels, books, packaging, or even implanted beneath skin.
Radio tags have been used commercially for delivering packages, handling luggage, tracking food in supermarkets and monitoring highway tolls.
www.wired.com /news/technology/0,1282,52343,00.html   (938 words)

  
 Verizon Wireless Radio Frequency Emissions   (Site not responding. Last check: 2007-10-22)
Your wireless phone, which contains a radio transmitter and receiver, emits radio frequency energy during use.
Scientific research on the subject of wireless phones and radio frequency ("RF") energy has been conducted worldwide for many years, and continues.
SAR is a measure of the rate of absorption of RF energy in the body.
www.verizonwireless.com /b2c/aboutUs/wirelessissues/radioEmissions.jsp   (831 words)

  
 RFID articles (July 2005)
Radio Frequency Identification (RFID) and the Defense Logistics...
Computing, The global radio frequency identification (RFID) market is poised for a dramatic shakeout in the coming six to nine months as firms struggle to develop the...
Financial Express, Radio Frequency Identification (RFID) may not be the stuff of science fiction, but it's not the kind of technology that you will find in the neighbourhood...
www.rfidalert.com /rfid_2005-07.html   (11269 words)

  
 Howstuffworks "How the Radio Spectrum Works"   (Site not responding. Last check: 2007-10-22)
You've probably heard about "AM radio" and "FM radio," "VHF" and "UHF" television, "citizens band radio," "short wave radio" and so on.
In this article, we will look at the radio spectrum and see what is really going on.
With a handheld or automobile GPS receiver you can track your location or find the quickest way out of any area.
electronics.howstuffworks.com /radio-spectrum.htm   (72 words)

  
 Cover Pages: Radio Frequency Identification (RFID) Resources and Readings
Passive tags that operate at frequencies up to 100 MHz are usually powered by magnetic induction, the same principle that drives the operation of household transformers.
When affixed to various objects, tags can be read when they detect a radio frequency signal from a reader over a range of distances and do not require line-of-sight orientation.
While WhereNet has long been working with RFID (Radio Frequency Identification) technology for improved resource management, Version 4.0 is the first of is kind, according to one analyst.
xml.coverpages.org /rfid.html   (9191 words)

  
 Radio Frequency Identification at Rfid-Tracking.Net   (Site not responding. Last check: 2007-10-22)
Inventory records can be used on behalf of recovery within the event a particular tool is stolen.
Radio Frequency Identification related phrases are on Rfid-Tracking.Net.
Just how faraway RFID comes is a particular query of tagging economics, in addition to time.
www.rfid-tracking.net /radio_frequency_identification.html   (665 words)

  
 NTIA: Office of Spectrum Management
The United States Frequency Allocation Chart is provided in the Adobe Acrobat Portable Document Format (*.pdf).
U.S. Frequency Allocation Chart as of October 2003 (Adobe Acrobat format) (Adobe Acrobat format).
Text equivalent version of the U.S. Frequency Allocation Chart as of October 2003 (Adobe Acrobat format).
www.ntia.doc.gov /osmhome/allochrt.html   (190 words)

  
 Radio Frequency Company, Inc., industrial RF processing systems for rapid heating and drying of materials
Radio Frequency Company, Inc., industrial RF processing systems for rapid heating and drying of materials
Radio Frequency Company's New Macrowave™ Pasteurization Systems are ideal for bulk applications for bagged or conveyed loose product.
Macrowave™ is a registered trademark of Radio Frequency Co., Inc.
www.radiofrequency.com   (120 words)

  
 [No title]
We carry both hobbyist scanner antennas as well as professional two-way radio antennas that are great for scanning individual radio bands.
We also offer a bi-monthy race frequency newsletter service to keep you updated on the ever-changing race frequencies used by each team.
The accessories are built with radio hobbyists, Hams, public safety and news media members in mind.
www.scannermaster.com   (1061 words)

  
 ARRLWeb: ARRL Home Page
Speaking March 7 at Jackson State University in Mississippi, Sarratt said Amateur Radio volunteers were tremendously effective in their ability to re-establish communication links using their own gear or by building systems from scratch.
The 31st International Amateur Radio Exhibition HAM RADIO 2006 will be combined with the 57th Bodensee Convention organized by the Deutscher Amateur Radio Club (DARC), the event's major patron.
In addition to the exhibition, HAM RADIO 2006, held in the Neue Messe Friedrichshafen, will feature a big flea market as well as lectures and presentations.
www.arrl.org   (1942 words)

  
 DHS | Department of Homeland Security | Fact Sheet: Radio Frequency Identification Technology
Radio frequency (RFID) identification technology refers to wireless systems that allow a device to read information contained in a wireless device or “tag” – from a distance without making any physical contact or requiring a line of sight between the two.
There is no one definitive “RFID technology,” but, rather, an enormous range of technical solutions that vary in their complexity and cost, depending upon the functionality, packaging, and applications for which they are used.
Radio frequencies emanating from RFID tags are far below the levels that could cause any harm to human health and below the typical ambient radio frequencies most people are exposed to in the United States on a daily basis from devices such as TVs and radios.
www.dhs.gov /dhspublic/display?content=4307   (702 words)

  
 ARRLWeb: US Amateur Radio Frequency Allocations
Practical Radio Frequency Test & Measurement -- Learn the basics of performing tests and measurements used in radio-frequency systems.
The Electronics of Radio -- This advanced-level textbook uses the practical approach of making a real ham rig (the NorCal 40A) to teach radio electronics.
The NTIA says that hams planning to operate on 60 meters "must assure that their signal is transmitted on the channel center frequency." This means that amateurs should set their carrier frequency 1.5 kHz lower than the channel center frequency.
www.arrl.org /field/regulations/allocate.html   (734 words)

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