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Definitions & table of signal & other frequencies from lowest to highest: this article defines and explains electromagnetic field (EMF) or electro-magnetic radiation EMR and related terms such as EMF, radio frequency - RF, hertz or cycles, megahertz, medium frequency MF, very high frequency VHF, ultra high frequency UHF, megahertz MHz, gigahertz GHz, terahertz THz .
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Definitions & Names of Different Radio Frequency or Electromagnetic Frequency Ranges: RF and EF Electromagnetic Fields
Before buying test equipment to measure the strength of electromagnetic fields, readers should review this article to be sure that they understand the types of electical fields that exist, the typical sources of different types of electromagnetic fields (power lines, AM and FM radio towers, cell towers, other equipment), and thus the type of test equipment that would be used to assess electrical field strength.
See ENVIRO-SCARE, EMF & Property Values if you don't know what EMF, ELF, or electromagnetic fields are or if you want a summary of the possible health effects of EMF exposure and the more likely effect on the property value of homes located very close to power transmission lines. Readers who intend to make their own EMF measurements should be sure to also see EMF MEASUREMENT WORKSHEET and also WORKSHEET for EMF MEASUREMENTS - Example. Also see Definitions of Gauss vs Milligauss for details about gauss and milligauss and definitions of these terms. Also see Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues which discusses the impact of EMF and other environmental concerns on property values. And see EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE which discusses EMF exposure in the workplace. The information provided here is for research and study purposes. The author makes no representation of unique expertise on this topic, other than having field experience in EMF measurement, having studied technical literature and having conversed with other experts and authors in the field for a number of years.
Electromagnetic fields, or EMFs are invisible lines of force created whenever electricity is generated or used. EMFs are produced by power lines, electric wiring, and electric equipment and appliances. The frequency of EMFs is measured in hertz (Hz, or cycles per second).
People are exposed to both electric and magnetic fields, but scientists are most concerned about magnetic fields. This fact sheet deals only with magnetic fields that have frequencies near 60 Hz the frequency of electric power in North America.
Static magnetic field around a bar magnet.
Health professionals, epidemiological experts, and in the case of EMF, electrical engineers can offer competent, expert advice which should be considered before any costly or risky actions are taken regarding this or other environmental topics. Use information at this website at your own risk.
Here are simple definitions of terms that you should know if you are concerned with RF or EMF hazards and where they might originate, or how they might be measured
Here we provide a summary of EMF, EMR, and radio frequency cycle rates, and where they are used. Our definitions are arranged in order of increasing frequency or decreasing wave length of electromagnetic signals.
So a typical low cost instrument suitable to measure power line EMF or Hz is not suitable for TV transmissions measurement in the
Definition of EMF - an EMF or electromagnetic field is the field or area of force caused by movement of an electrical charge and containing some amount of electromagnetic energy.
Definition of EMR - Electromagnetic radiation, or electromagnetic radio frequency radiation EMFR. EMR or electromagnetic radiation is electrical and magnetic energy emitted by various types of energy sources: radio waves, microwaves, light, x-rays, and nuclear energy and sometimes expressed or measured in photons (particles) or as waves (discussed here).
EMR or EM radiation is the result of oscillating electrical and magnetic fields that move as an energy force in wave form through space.
Depending on the wavelength of a particular EMR source, it may be visible to the human eye (in the light spectrum).
While we provide more detailed definitions of types of EMR in this article, roughly EMR is divided according to its wavelength (in order of decreasing wavelength) into electrical energy (such as 60 cycle electrical current in a home, electrons oscillating in an electrical wire), radio waves, microwaves, visible light, ultraviolet light, x-rays, and gamma rays. The higher the frequency of EMR the shorter is its wavelength. In general, electromagnetic radiation (EMR) is synonymous with electromagnetic waves.
Depending on wavelength, energy level, exposure, distance, and other factors, the biological effects of EMR may be heating (warming a chicken leg in a microwave oven), or ionization (knocking an electron off of a molecule to create an ion), to possibly profound effects on molecules or on cells of living tissue.
Definition of Ionizing radiation - ionizing radiation is electromagnetic waves powerful enough to change (ionize) molecules of a substance (human tissue, for example) that they strike. Ionizing means creating an "ion" form of a molecule - that is, detaching an electron, converting the molecule to an "ionized" form with a different electrical charge. Ionizing radiation is known to be dangerous to humans and other animals.
It is the energy level of an electromagnetic wave that causes it to become ionizing, not the number of waves that occur. Short-wavelength (high frequency UV [ultra violet], X-rays, gamma rays) radiation is ionizing while low-frequency radiation is not.
Examples of ionizing radiation include high frequency radiation such as from X-rays, gamma rays, or nuclear radiation, alpha rays, beta rays, and neutrons from a nuclear reaction.
Definition of Non-ionizing radiation - low power non-ionizing radio waves at low levels of transmission power, such as older analog cell phone signals and cell phone radiation.
Definition of SAR & SAR Limits - Specific Absorption Rate of Radiation - measures the amount of radiation that a human body absorbs from a source such as from a nearby radio transmitting antenna or cellphone (radio receiving antennas do not emit EMF). In the United States the FCC requires that the SAR for cell phones is required to be no more than 1.6 watts per kilogram.
The following table summarizes the radiation frequency (cycles per second or Hertz or Hz) and wavelengths (physical length of waves) for various types of electromagnetic radiation sources such as radio waves, microwaves, light, and x-rays. The EM range or EM frequencies extend from a low end of about 1 kHz to 2.4×1023 Hz. - Wikipedia 6/10.
Notes to the table:
Please see our full article on this topic found at Cell phone Radiation Hazards. Excerpts from that article are below. Readers of this article should also see EMF RF FIELD & FREQUENCY DEFINITIONS and EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE
Definition of cellphone radiation - cellular telephones, because they include a radio transmitter, emit electromagnetic fields (EMF, or EMR).
In the United States the Federal Communications Commission (FCC) specifies the allowable limits of cell phone radiation. A possible concern is the exposure of the human ear and brain to cellphone radiation, especially as newer digital cell phones operate at higher power and at frequencies in the 1800-2000 MHz range. Present cell phones may exceed the FCC EMR limit that was set when most cell phones were analog in signal design and emitted lower-strength EMFs in the 800-900 MHz range.
Scientific research on possible health hazards from cellphone use to date (2010) has produced inconclusive and conflicting results, varying by study. According to an article in June 2010 the New York Times,
What type of radiation is emitted by a cellphone? older cell phones emit and receive low level radio frequency waves from 200 MHz to more than 800 MHz. Newer cell phones operate in the 900 MHz to 2.4 GHz or more (approaching the power and frequency of microwaves and infrared waves). Transmission of signals in the cellphone range are also referred to as UHF or Ultra High Frequency Signals.
Base to Mobile and Mobile to Base Cellphone Frequencies May Differ
It is worth noting that typically the signals that pass between a cell phone and a cell tower are at different frequency ranges depending on the direction of transmission. For example, a cell phone may transmit from the phone to the cell tower at around 800 MHz, while the tower transmits back to the cellphone at around 1800 MHz.
Because the power level of a cellphone while it is transmitting is very small compared to the powe of the cell phone tower when it is transmitting, that means that the stronger of the two cell phone frequencies is the tower transmission signal. In reading various publications that discuss cell phone frequencies, you may read the cellphone transmit frequency as "mobile to base" and the tower transmit frequency from tower to cellphone as "base to mobile".
Cellphone Abbreviations and Terms - What Frequencies Your Cellphone Uses Depend on Your Wireless Carrier as Well as the Phone Itself
AMPS - Advanced Mobile Phone Service - Cell phone industry standard since 1978
Analog service: radio signals modulated to carry information in a continuous signal, like FM radio. Receiver and transmitter use the same frequency.
Digital cell phone service: radio signals are digitized using a binary code (0's and 1's) to convert speech (or any signal sent to or received from a cellphone) to binary data. In the U.S there are 3 wireless technologies: CDMA, TDMA, and GSM.
- 800 MHz band authorized by the U.S. FCC in 1987 for cellphone use.
PCS - Personal Communications Services - 1.9 GHz all digital transmission and reception authorized by the U.S. FCC
SIM cards - Subscriber Identity Module cards are small printed circuit boards that contain individual cell phone account information and that are inserted into GSM phones (in the U.S.). Because the SIM card contains the user information, cellphones that accept SIM cards become generic - you can move your cell phone account to a new telephone by inserting your SIM card into a new phone, or you can change your cell phone to a different service provider (and telephone number) by buying and inserting a different SIM card into your existing GSM phone.
Please see our full article on this topic found at Cell phone Radiation Hazards.
Frequently Asked Questions (FAQs) about the definitions of Hertz & various frequency measurements
Question: is it unhealthy to live near an AM radio tower?
Do you think it is a health hazard for a sensitive person to live near AM radio towers that emit 5,400-6,000 mV/m? The AM station frequency is 1260. Thanks. - Sarah 8/3/2011
Sarah AM radio stations transmit medium frequency radio waves, not low frequency EMF; The U.S. FCC reports no health hazard from exposure to AM radio transmissions from RF (radio frequency) transmissions. But at least some research shows that exposure to high levels of RF may be harmful. Because the jury is likely to remain out on this topic for some time, a reasonable approach is that of "prudent avoidance" - meaning that you would take reasonable steps to avoid prolonged exposure to high levels of EMF or RF energy but you would not panic, spend thousands of dollars on questionable "magic bullet" remedies, etc. You can start by determining just what your exposure is by duration, distance, and signal strength. As we describe in these articles, inexpensive RM measuring equipment is available from a number of manufacturers.
Question: reader fears people are being decimated by EMF
I would particularly like to know how you presume your enviro-scare bell curve has any bearing on reality given that people are likely to be debilitated or decimated, keeping the alarms on environmental hazards muted. Please forward me a copy of this e-message with your response to it. - email@example.com 12/19/2012
Reply: clarifying the definition of Enviro-Scare
Annie, your question is unfortunately based on what appears to be your own presumption of level of risk, and sadly, reports that "people are likely to be decimated" - which I understand to mean "slaughtered wholesale" (a stunning remark for which you offer no authoritative citations regarding electromagnetic fields). Compounding these errors you presume that we are motivated to "mute environmental hazards" - an incorrect conclusion regarding our concern for public safety that is readily apparent from reading any of the thousands of articles found at InspectApedia.com.
Lastly, you have perhaps missed the point of the bell curve that is used to desribe Enviro-Scare, so let me try to clarify that topic. Enviro-Scare refers to the observation, made over decades, that regardless of whether or not a particular environmental hazard is found to be real or imagined, the level of public fear about the hazard follows the pattern of a bell curve, increasing as news reaches the public, reaching a peak, and eventually falling off to near zero, independent of the actual level of risk.
Annie, it is indeed important to take real risks seriously, and at the same time, to set our priority of attention to be sure that we address both great and immediate risks first, as well as subtle and longer term risks such as those that may be present from various environmental contaminants. In other words, if you break your neck falling down the stairs, the fact that you were exposed to DES as a child in utero will pale in significance.
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