In 2011 the World Health Organization classified cell phones (and other wireless devices) as a possible carcinogen due to radiation emissions. In 2013 Dr. Anthony Miller from the University of Toronto's School of Public Health recommended that based on new research, radio frequency (RF) exposure should be reclassified as a probable carcinogen. Dr. Martha Herbert, a Harvard Pediatrician, wrote in this 2013 letter that "thousands of papers...document adverse health and neurological impacts of EMF / RFR." In 2013 the American Academy of Pediatrics requested a review of EMF radiation emissions from technology devices, citing impact on children.
What are RF Electromagnetic Fields? RF stands for "Radio Frequency", which includes electromagnetic fields (EMFs) from mobile phones, cell and mobile phone towers, radio and TV towers, Wi-Fi, and microwaves. Physically, these are electric and magnetic fields vibrating faster than 3 kHz and usually moving together as waves. For EMFs from home wiring and power lines see AC Fields in Homes.
What does the RF meter measure? Our RF Meter measures the RF field strength in Volts per meter (V/m), and the time-average RF power in uW/m2. This measures the RF that people are exposed to. It measures RF at frequencies from 150 MHz to 10 GHz, but it does not display the frequency. An RF meter does not measure static or low-frequency fields from magnets, the earth's magnetic field, power lines, nor home wiring, for those you would use a different meter: see Gaussmeters at top of page.
What is frequency in Hz, kHz, MHz, or GHz? Frequency in Hz is how many waves per second. kHz is a thousand waves per second, MHz is a million waves per second, and GHz is a billion waves per second. So 1000 Hz = 1 kHz, 1000 kHz = 1 MHz, 1000 MHz = 1 GHz. Higher frequency is not necessarily worse than lower frequency. Higher frequency is not the same as higher RF exposure.
Explain the units of Average RF power. Our RF meter displays the Average RF power in uW/m2 (microWatts per meter square).
The "u" stands for "micro" (1 millionth in standard scientific notation).
Another widely used unit is "Watts per meter square" (W/m2), so 1 W/m2 = 1 million uW/m2
Our RF meter can measure from 1 to 100,000 uW/m2 (which is up to 0.1 W/m2).
Other standard scientific prefixes are sometimes used, for example: 1 mW/sq.cm = 10 W/m2 = 10 million uW/m2, and 1 nW/cm2 = 10 uW/m2.
This RF meter provides a much more accurate Average RF power reading than most RF meters. This RF meter was selected for its accuracy, ease of use, wide frequency range (150 MHz-10 GHz), and excellent sensitivity (it can measure weak RF signals). Most RF meters use a simple formula which only computes continuous wave (CW) RF power from the V/m, which vastly overestimates the average power of most modern digital RF signals transmitted in digital bursts. Our RF meter displays a far more accurate true time-averaged power reading using 1024 samples, which is much more accurate for modern digital RF signals than other RF meters in this price range.
What is considered a safe level of RF exposure? There are varying opinions about this from experts around the world. In 2005 a group of German doctors wrote an open letter to the President of Bavaria which recommends public exposure should be below 10 uW/m2 average RF power (which is near bottom of the "Average" scale on our RF meter).
New Zealand has a 500 meter (1/3 mile) buffer around mobile phone towers where no one is allowed to live.
Most other governments allow a much higher level of RF exposure (see next question).
What are government safety standards for RF exposure? Different countries have different standards and it also depends on the frequency and length of time of exposure. In the USA the limit for RF average power exposure of the public is:
2 W/m2 (=2 million uW/m2) at frequencies of 100 MHz to 400 MHz
2 to 10 W/m2 (=2 million to 10 million uW/m2) at frequencies of 400 MHz to 2000 MHz
10 W/m2 (=10 million uW/m2) at frequencies of 2000 MHz to 5000 MHz.
Some countries have lower limits than US: in Canada it is 3 W/m2 (3 million uW/m2) at 1800 MHz (Safety Code 6, 1997).
In Italy, Switzerland, Poland, and China it is 0.1 W/m2 (100,000 uW/m2) at 1800 MHz.
If our RF meter is showing below its maximum average reading of 100,000 uW/m2 then these government standards are being met (usually by a wide margin). However, some studies have found adverse health effects at levels far below these government standards (see other questions on this page). Our RF meter can measure much lower exposure levels: from 1 to 100,000 uW/m2.
What is the RF exposure while using a mobile phone next to your head? A typical mobile phone produces average power of about 25 W/m2 (=25 million uW/m2) on the outside surface of your head and 3 W/m2 (=3 million uW/m2) inside your cranium near the phone. The peak V/m is around 300 V/m on the outside and 100 V/m on the inside of the head. For a child their head is smaller and their brain still developing, so this very high exposure is of even more concern. James McNamee with Health Canada in October of 2011 issued a cautionary warning stating "Children are more sensitive to a variety of agents than adults as their brains and immune systems are still developing, so you can't say the risk would be equal for a small adult as for a child." (Globe and Mail 2011). Mobile phones are required to be tested for SAR which measures how much RF power is absorbed in the head as heat, but it does not consider other possible effects besides heating, and also the government assumes adult users will not use their phones for longer than 30 minutes per day, and children for even less time.
Can the RF meter measure WiFi and Bluetooth? Yes. Distance reduces RF exposure, so you could place the WiFi router away from bedrooms and other locations where people spend a lot of time, and turn off WiFi routers at night especially if they are close to a bedroom. Different WiFi devices emit differing amounts of RF power. WiFi routers that need to cover a wider area like schools often radiate at higher power, and should be placed farther away from where children sit. Bluetooth radiates lower power than WiFi but is sometimes worn very close to the head. This video shows the RF meter measuring a WiFI router or modem: www.youtube.com/watch?v=ICA19oKPi5I
Where are cell towers located? www.antennasearch.com shows locations and frequencies of many towers and antennas in USA.
RF exposure will depend on the distance from the tower, your height above ground compared to the tower antenna height (being closer to the antenna height is worse), the number of carriers, operators, and antennas using that tower, the power transmitted by each antenna, antenna patterns, frequencies, type of walls and roof material in your building, metal objects in your vicinity, etc. You can get some general info about most towers in the USA such as location and frequency from www.antennasearch.com. You can also measure the RF exposure using the RF meter and compare it with other locations.
There is an antenna on my building or nearby building: First, find out what type of antenna and what its used for: some antennas are for receiving only (like TV antennas on houses, satellite TV, and some satellite internet antennas), those would not transmit anything so they would not cause any RF exposure nor show anything on the RF meter. See if the building address is found at www.antennasearch.com which gives some information about many transmitting antennas in the USA. Ask the owner of the building or the antenna what type of antenna it is. If it is a cell phone antenna then see the above FAQ about antenna towers near your house. Antenna beams usually direct more power horizontally than downwards, so its possible to have more exposure on an upper floor of a nearby building than on a lower floor in the same building as a rooftop antenna.
Could there be a cell phone antenna on the wall of my building? Sometimes a cell phone company has been allowed by the landlord to place an antenna on the outside wall of an apartment or office building, which exposes the occupants in the nearest rooms to high RF fields. These antennas may be as small as a shoe-box and painted the color of the exterior of the building to blend in. These antennas can be located using the RF meter, since the fields get stronger as you approach the antenna.
Can the meter measure RF power from cell phone towers, TV and radio broadcast towers? Yes, except not AM radio towers since AM frequencies are below the frequency range measured by this meter.
There is a TV tower near my house, what is our RF exposure? Exposure from a TV tower was about 10,000 uW/m2 at 1/2 mile (800 meters) from the tower. You can also measure it using the RF meter. Health problems were found near radio and TV towers due to EMF / EMR RF environmental exposure: see page 3 of www.powerwatch.org.uk/library/downloads/rf-emfs-1-intro-2013-10.pdf
If I want to reduce RF exposure from a nearby tower or antenna, what can I do? Aluminum siding will block most RF radiation. RF waves travel mainly in straight lines from the source and are blocked by metal, so you actually only need the aluminum siding on the sides of the house facing the tower. In attic areas you can staple chicken-wire to block rays from the top of the tower from entering the house from above. Aluminum mosquito screens will block RF and can be used over windows. Conductive paint is available which will block RF. Conductive fabrics can be used over walls or ceilings or for curtains, drapes, or shields (conductive fabrics are usually copper color or gray color and are very flexible and can be sewn like most fabrics). Aluminum venetian blinds (vertical) in front of windows will block some RF. Aluminum foil also blocks RF. These all work due to the high frequency of RF; the RF can still go around these shields but is much reduced in strength. (But these methods would not block 60 Hz magnetic fields from power lines, measured with an AC gaussmeter).
Can the RF meter measure TV or radio sets in my home? TV and radio sets are receive-only and do not transmit any RF power, so there should not be any RF coming out of a home TV or radio antenna. Two-way radios however can transmit and could be measured by this meter if they operate at 150 MHz or higher frequency.
Can the RF meter measure Ham Radio antenna transmissions? Not most ham radio transmissions, since they are usually below the 150 MHz frequency which is the lowest frequency measured by this meter.
Is there an easy way to reduce RF exposure? For mobile phone conversations you can use an earbud or speaker so the phone is not next to your head. You can place the WiFi router away from where you spend a lot of time. You can use the RF/Cell Tower Meter to measure RF exposure in areas you spend a lot of time, and if it is below 10 uW/m2 Average, and you don't live near any AM radio towers, then you should have low RF exposure.
© 2015 Magnetic Sciences