Typical EMF & RF Sources in the Home

Homes have several potential sources for high EMF and RF sources including:

  •  External high voltage power lines (both primary and secondary feeders) which can produce elevated levels – particularly in densely populated urban areas / cities such as Dallas, Fort Worth, Houston, Austin, etc. or in homes near utility easements
  •  The main 120/240 volt feed entering the home through the power drop
  •  Breaker boxes
  •  Fluorescent lights (some also have an RF component as well which can cause equipment interference)
  •  High output halogen lamp banks such as those used in track lighting (uses a lot of current)
  •  Appliances with motors or heating elements (washers, dryers, refrigerators, etc.)
  •  AC Adapters
  •  Wiring Errors
  •  Outside Air Conditioning Compressors and Pool Equipment
  •  Wireless Routers, Cell Phones, Bluetooth and Cordless Phones (radio frequency only)
  •  Smart Meters (but fairly low level)
  •  Dimmers (though the range tends to be very short, but I have seen them wreak havoc with sensitive electronic equipment)

The focus should primarily be in areas exposed to EMFs where occupants spend 90 % of their time or greater – this sample schematic gives examples.

Focusing on areas where people spend 90% of their time

Focusing on areas where people spend 90% of their time

LFE means Low Frequency Electromagnetic – this is the typical ELF (Extremely Low Frequency) band for 60 Hz AC power

Typical Low Frequency 60 Hz EMF

Typical Low Frequency 60 Hz EMF Sources

Higher frequency RF sources in the home including wireless routers, printers, laptops and other portable cell phone / tablet devices – DECT means Digital Enhanced Cordless Telecommunications

Typical High Frequency RF Sources in the Home

Typical High Frequency RF Sources in the Home

The Difference Between Electric and Magnetic Fields

Alternating Current (AC) & Direct Current (DC) Fields

Direct current is simply a constant voltage with no change in polarity. (see the red line below) It is commonly found in batteries and is the output for virtually all AC adapters that plug into a wall.

Pulsating signals as shown in blue below are technically considered DC since the current never drops below the 0 axis line marked with the horizontal arrow. This output is what you would find on the output of a AC-DC power supply or other DC supply that has periodic noise on it.

Alternating current changes the direction of current within a conductor over some period of time. This is the form of electricity found in virtually all power generation and transmission over high voltage lines and in home electrical wiring.

AC power is almost always sinusoidal, but other forms of periodic AC can be signals in the form of sawtooth, triangle or square.

The variable gray signal shown below which crosses from negative polarity (below the horizontal axis arrow) to positive is more typical of a noise signal, though in the time domain it more likely to take the form of a transient signal or noise spike such as might be seen in lightning, a spark or arcing.

Comparing Alternating Current and Direct Current

Comparing Alternating Current and Direct Current

AC EMF fields vary in property based primarily on frequency regimes with respect to the size of the object they are affecting. Here are the three main domains they fall into:

I. Wavelength of the field is much larger than the object they are affecting – this includes ELF frequencies such as 50 Hz in Europe and 60 Hz in North America. The wavelength of a 60 Hz field is approximately 5000 kilometers or 3100 miles which is much larger than the human body.

In this regime, the E fields (Electric) and B fields (Magnetic) can exist independently or in engineering terms they are known as “uncoupled”. This is a consequence of quasi-static EM field theory which is a low frequency approximation for calculating such fields. The other theory which is used is electric circuit theory which involves Kirchoff’s Voltage Laws and Kirchoff’s Current Laws.

II. Wavelength of the field is approximately the size of the object they are affecting. This approximation is within an order of magnitude. (also known as a power of 10)

III. Wavelength of the field is small compared to the size of the affected object.


Simply put, the electric field is a function of voltage potential between any two points. (in the case of the lamp below, there is a voltage difference between the hot and the neutral in the wire) The greater the voltage difference and shorter the distance, the higher the field.

The magnetic field is a function of current flowing through a conductor. In general, the higher the current, the greater the field though there is a “falloff” over distance.

As mentioned above, ELF frequencies such as 60 Hz AC power have electric and magnetic fields which are uncoupled or independent from each other. In the picture of the lamp below, the electric field is some non-zero value, but the magnetic field is 0 until the switch is turned on and current flows.

Electric Field present with voltage, Magnetic Field depends on current

Electric Field present with voltage, Magnetic Field depends on current


Notice that the electric field projects straight out from the cord while the magnetic field curls around the wire and follows what is known as the right hand rule as shown below.

Right Hand Magnetic Rule with respect to Current Flow

Right Hand Magnetic Rule with respect to Current Flow

Radon Safety Inspections: More Interesting Facts You Didn’t Know

Some of you are aware from reading my blog or elsewhere that radon gas exposure is estimated to cause 15,000 – 20,000 deaths in the United States but is even more likely to affect smokers.

But how much more?

As of this writing it is estimate that radon is responsible for 3-5 % of all fatal lung cancers, but specifically up to 10-15 % for smokers.

In the chart below, you can see that radon gas contributes the majority (over 1/2) of the harmful radiation that an average person is exposed to over their lifetime including medical X-Rays.

Radon Gas Overall Contribution Chart

Radon Gas Overall Contribution Chart

Where does the radon gas come from?

Much of it is from soil exposure, but a sizable contribution within indoor dwellings comes from building materials such as brick, concrete, etc. and particularly stone such as mildly radioactive granite and marble which are found in kitchen and bath counter-tops. (ScanTech can test natural stone materials for excess radioactivity) Other potential sources are in the water and natural gas supplies; even in burning coal.

Radon is soluble in water, particularly cold water and can be released while cooking, bathing and cleaning. It can also find it’s way into the breathable atmosphere through commercial activities such as ore processing, burning of coal in power stations and the use of agricultural fertilizers.

Radon Safety Inspection Inspector Dallas

Radon Safety – Indoor Dwellings Contribution Pie Chart

One interesting property of note with radon is that is has a rather strong diffusion ability, which means that it spreads out and infiltrates air and water easier than many other substances. The official diffusion coefficient is 0.12 cm^2/sec in air and 1.37 * 10^-5 cm^2 in water at 25 C. (roughly room temperature)

The solubility coefficient is the measure of gas solubility in water. It is defined as the ratio of the radon concentration in water to that in air. At 20 C, the solubility coefficient is 0.25 which means that radon is distributed preferentially in air rather than in water. (a ratio of 4:1) The radon solubility is 510 cm^3/L at 0 C as the solubility of radon goes up in colder water. (this is rather the opposite of most other chemical substances where the solubility tends to go up the warmer the water)

More Interesting Facts About Thorium and Radioactivity

While the radon decay series is well documented on the Internet, the thorium radioactive series is hardly mentioned so I have included it here for convenient reference.


Thorium-232 Decay Series

Thorium-232 Decay Series

Incidentally, alpha particles are the most effective ionizing agents but generally cannot penetrate very far into any material (even in air it loses energy at the rate of about 1 MeV per cm) so that must be internalized in the body to do harm. An alpha particle would require at least 7.5 MeV of energy to penetrate skin due to the top layer of the epidermis being composed of dead cells.

Only Polonium 214 at 7.69 MeV emits alpha particles energetic enough to penetrate the skin. (it is suspected of being the cause of skin cancer in miners) However once inside the body (such as through inhalation) a 5.5 MeV ejection energy can penetrate about 40 um into soft tissue which is about the length of 4 cells.

But the alpha particle would have produced about 160000 pairs of ions before it loses all of its energy. In comparison, this is about 40000 ion pairs per cell versus an average of about 60 ion pairs produced by a 2 MeV beta particle.


Weak Cellular Phone Reception: Why and What you Can Do About It

Cell tower survey, weak cellular reception

Weak or no cellular signal

One bar.

Or none.

The frustration of being in an out of service area, dropped calls, intermittent voice communication, slow download speeds… all issues we have experienced at one point or another. If you happen to work or live in a “dead zone”, then it can be exceptionally inconvenient to pay for a service which is inadequate for your needs.

So with all of the cellular towers that seem to be around, why does this scenario keep occurring into the 21st Century? There are several reasons:

Your carrier may not have particularly good coverage in areas you need your phone to work. In my surveys, I have definitively found that some cell phone companies have invested more in their infrastructure than others.

Your location may be in a non-ideal area geographically with respect to the cell phone signal such as in a valley or a heavily wooded area. In valleys, the signal from cell towers tends to pass overhead and/or is shadowed by the terrain. Trees and foliage have leaves which contain water; water tends to absorb cellular tower radiation (which is how your microwave oven works) and attenuates (weakens) the signal. Older neighborhoods with large trees tend to have more issues than the newer, wide open suburbs.

Inside certain buildings, there may be certain building materials including thick glass, stucco and metal in the structure walls and ceiling to act as RF shielding or significantly weaken the indoor signal. This is why getting closer to a window or stepping outside can make a significant difference. Have you ever noticed how you almost always drop a call inside of an elevator when the doors close? That is because you are effectively inside of a Faraday Cage, which is engineering talk for an enclosure which blocks off virtually all radio frequencies. Also, in a downtown area, large buildings can “shadow” you from a cellular repeater and lower the signal strength.

Your phone itself may not have the best reception which could be due to everything from a poor signal to noise ratio, insufficiently sensitive receiver, internal noise, etc. One big difference is that cell phones now rarely ever have external antennas which are almost always superior to the internal ones hidden inside on a printed circuit board. Why were they done away with? Some of it probably has to do with aesthetics, others practicality, (who wants a piece of wire that can snag on a pocket) and mostly I believe it was a warranty issue with the manufacturers.

With a relatively thin piece of metal sticking out, how many times do you think consumers brought their phone in because of a broken antenna? This costs the manufacturer if under warranty, downtime for the customer, etc. Personally, I wish the option to hook up an external antenna for areas of unusually poor reception were present, but that will probably never happen with the exception of repeaters. (discussed below)

Certain times of day and areas may experience high call / data download volume and use up available bandwidth. If everyone is trying to call using the same cell site, it can get overloaded which is why you get an occasional voice message telling you your call cannot be completed.

So what can be done?

Some of the obvious choices are changing carriers and/or researching phones for better reception. You can also get repeaters that are either specific to your carrier or will work with multiple carriers. Many phones can now be set to Wi-Fi calling, (and borrow the local Internet connection) but I find that sometimes my phone works more reliably if I leave it off as an open wireless connection may not always be available. (and tends to force some models into an annoying hunting loop that disrupts communications) If you really need to get a message to someone, text is far more reliable than voice. Why? Because voice calling requires a continuous stream of data and bandwidth in real time that is relatively error free, while a text message takes up far less bandwidth to send and can be reassembled in order that not dependent on happening in “real time.”

Another option, particularly for commercial applications and clients is to contact ScanTech regarding your needs for an cellular strength survey and evaluation. We cover all major carriers such as Verizon, AT&T, Sprint and T-Mobile and offer a variety of ways to assess what is causing the issue and how to best address it.

Sound Levels: Safety vs. Hearing Damage & Loss

Because sound pressure levels are measured on a logarithmic scale, (power ratios of 10) an increase in decibels beyond a certain point means that the energy impacted on the ear can quickly pass a threshold where damage can occur. As shown in the chart below, even an increase of 5 dB can greatly reduce the duration before hearing loss can occur.

Sound Levels vs. Physical Effects

Sound Levels vs. Physical Effects

Note that sound levels above 70 dB begin to interfere with voice communication, while 75 dB and above are generally characterized as annoying. (but dependent on frequency as shown below)

The general effects can be studied in the response table below:

Hearing Damage from Different Noise Levels

Hearing Damage from Different Noise Levels

Fortunately, sound pressure levels also decrease with the square of the distance, so moving twice as far away means that the power level decrease by a factor of 4. Bear in mind that 3 decibels (dB) reflects a change in power level by a factor of 2, with +3 dB being twice as loud and -3 dB being half as loud.

Sound Level Decrease with Distance

Sound Level Decrease with Distance

Also, the human ear does not have a “flat” frequency response – so frequencies at the extreme edges of hearing perception (from 20 Hz to 20,000 Hz) are not perceived to be as loud as those centered around 1 KHz – 3 KHz which is in the range of normal human speech.

Perceived Human Hearing vs. Frequency

Perceived Human Hearing vs. Frequency

Therefore, different measuring scales on sound meters are used to distinguish between “human” hearing (dBA) and “machine” hearing (dBC) which has a flatter frequency response.

Sound Weighting of dBA dBB and dBC Curves at different frequencies

Sound Weighting of dBA, dBB and dBC Curves at different frequencies

Smart Meters: Home Safety with regard to Actual RF Testing

Smart Meter, RF, Safety

Model GE I-210 Smart Meter

The controversy of Smart Meters is getting so prevalent that I feel a compulsion to share some of my data with respect to certain claims and fears that the public has about this deployed technology. There are a number of website and organizations dedicated to banning this device for various reasons. Some of them deal with potential privacy invasion issues or the theory that the power company can somehow selectively turn off certain appliances without your permission.

While I cannot comment on the political or civil liberties aspects of the Smart Meter debate, I have now done enough measurements to get an idea of just how much energy these devices are putting out and probable public exposure.

The short answer is: not that much.

Now before you think that I am on the side of the utility or power companies, I actually have some criticism of at least one power company’s portrayal of how low the levels from Smart Meters are:

Smart Meter RF Safety Homes

Smart Meter RF Comparison Chart (BTW, I do NOT entirely agree with this)

For one, I cannot believe that a Smart Meter puts out less RF than what emanates from a human body (I have no idea where they are getting that notion from – even brainwaves are severely attenuated outside of the body which is why electrodes are needed for EEGs) or the earth itself – at least not at point blank range.

And this brings up another hidden factor – at what distance from the source are these measurements taken? Because radiated power from an ideal isotropic antenna falls of with the square of the distance, if you even move the measurement meter a few feet from an RF source, the power levels drop dramatically.

Also, they are using milliWatts per cm^squared instead of the more typical microWatts/cm^2 (or uW/cm^2) which is more routine for measuring low level RF at a moderate distance. I suspect the reason why is because in using the milliWatts convention (in which 1 milliWatt or mW is = 1000 microWatts) you get to put all of those zeros after the decimal place and make the numbers seem even smaller.

There are specific reasons why I have chosen to point these specific concerns out besides just being picky – they also inform the reader to pay attention to the context in which this data is presented.

I just got done measuring my Smart Meter and at a distance of 3 feet which is as close as anyone would even causally walk past it, I only get a maximum of 1.5 uW/cm^2. That only occurs in a very short burst (less than one second) every minute or so, so the actual exposure averaged over time would be far less. (closer to the nanoWatt range) Please note that such an intermittent burst is NOT the same as the pulsed signals that you read about as being harmful. Those are frequencies are continuously pulsed in at least the MHz or GHz range – what I am talking about is more like a substantial fraction of Hertz or 0.016 Hz if it is one second out of every 60.

My cell phone when running at full power puts out over 2 uW/cm^2 and it is right next to my head when making a call. While the frequencies involved are somewhat different, the RF dosage is roughly comparable except that the cell phone is consistently much closer to my body for more extended periods of time. I doubt I spend more than 30 minutes a week being within 10 feet of my Smart Meter.

What non-technical critics also fail to realize is that the metal backing of the case on the Smart Meter which is in between the RF and the occupants inside the home is grounded and right next to the point source – therefore shielding much of what is already fairly low level RF.

Also what many people seem to forget is that the Smart Meter mounting locations are at the main power feed or drop into the home where the magnetic field tends to be the strongest. Therefore as a very respected EMF consultant pointed out recently, it is not the RF from the Smart Meter that should be such a concern, but the elevated magnetic fields that you get in the vicinity of any major power feed into the home.

But the bottom line is that if someone is convinced that a Smart Meter installation at their home is a threat to their health or the well-being of their family, then there is no sense in arguing the point.


My primary role is not to change someone’s mind, but to help them find peace of mind with a set of feasible solutions. Have you ever had something that seemed small, like a cupboard door that doesn’t hang quite right, or an argument with a coworker that just stuck with you all the rest of the day? We are unsettled because of the feelings of things not being symmetrical or completely in our control and regardless of the actual relevance or meaning, it causes stress and stress is definitely a factor in disease, accidents and our enjoyment of life.

So for legal Smart Meter mitigation, what I CAN recommend is a particular form of shielding that is currently approved by the local utility here in Dallas, Texas (ONCOR) that can be placed over your meter. By my measurements it reduces the RF by at least 95 % and I know someone who has at this writing has ONCOR’s express permission to install them. (installing one yourself can get you into trouble with the utility company if you remove the locktag to access the backside of the meter)

Please contact me at www.scantech7.com for details if you are interested.

BTW, trying to make one yourself such as a solid Faraday cage will probably block the data signal and also get you into trouble with the electrical company. The price of one installed by this particular gentlemen compares very favorably with other units sold on the Internet. Furthermore, it is rugged and designed to be vandal resistant so even if RF protection is not of interest, it may be a good investment for commercial customers looking to reduce the costs of malicious destruction.


EMF & Powerlines – Are the Health and Safety Effects Worth it? A Dallas Inspector’s View

High voltage powerlines, Smart Meters, the cell phone pressed up next to your head… are the effects on your body worth the risk?

I am a professional EMF inspector who has been practicing here in the Dallas – Fort Worth area for nearly the past 15 years and I have some informed thoughts on this subject based on my extensive education, experience and research into this controversial subject.

But before you click away in either fear or skepticism, let me reassure you that my viewpoint on this subject is actually very moderate. I do not demonize the utility companies or the electrification of our society, but neither do I ignore the potential health concerns that many share or the studies that have suggested some possible risks.

North American Life Expectancy Chart Over 100 Years

North American Life Expectancy Chart Over 110 Years

I look at both the pros and the cons of having power on tap in a wide variety of locales. Think back to the turn of the century, (the other century) say about 1900. The average life expectancy of a North American was roughly 47 years – give or take depending on what region of the country, gender, etc.  And in the 130 odd years since Edison switched his first electrical power plant on, the average life expectancy here in the USA has increased by at least 31 years to the age of 78 while the fields we are exposed to daily have gone up by several orders of magnitude. (I recently saw the figure of 16000 times greater)

So if power lines were so harmful, why are we living longer even while our society has become even more electrified?

Obviously, they are not immediately lethal unless you make direct contact in an unfortunate manner, nor are any consistent effects observed at moderate levels. However, I am not saying there is no effect whatsoever. But I feel that many advocates of a “gauss-less” life are missing all of the benefits that electricity brings.

Illuminated roads and buildings at night, hospitals and homes that do not operate by the far more dangerous gas lighting, air conditioning in the sweltering summer, emergency help just 3 digits away…  all of these modern conveniences converge to turn survival from a struggle into something that we can do without much thought.

So why do I perform EMF inspections? Because despite these advantages, people have legitimate concerns and have a right to make informed choices about where they work, live, sleep and spend their leisure time.

I am not a fearmonger, and my goal is to translate the latest findings of science and health research into an understandable context that makes living near powerlines and cell towers less of an unknown.

More to come soon, but for additional information or a survey, feel free to browse the following informative website:


Pacemaker / Biomedical Implant Electromagnetic Interference EMI Sources & Issues

While pacemakers and other biomedical implants and implantable devices are somewhat more resistant to electromagnetic interference (EMI) than in previous generations, there are also more sources of potential EMI from new technologies such as hybrid vehicles, wireless chargers and so forth.

For example, the DC magnetic field from headphones can exceed 10 Gauss and can demonstrably interfere with the operation of a pacemaker. Cardiac centers a few years ago did a study and found that up to 15 % of patients with a pacemaker experienced interference issues when headphone came within 1.2 inches of the device, and up to 30 % of patients with an ICD (Implanted Cardioverter Defibrillator) also demonstrated operational abnormalities caused by the close proximity of the speaker.

While cell phones and MP3 players are less likely to cause issues, they should still be kept away from the heart / bioimplant area as there is a chance that RF energy from these electronic device could cause unpredictable behavior. Several years ago, there were some studies that indicated that MP3 players themselves (separate from the magnetic field of the speakers) could not affect a pacemaker, but since then MP3 players have evolved to other transmission modalities which involve using radiated Bluetooth frequencies.

Also, very recent studies (June 2015) have shown that cell phone can influence pacemakers in unexpected ways. At close range (within 6 inches) pacemakers can misinterpret the signal from a cell phone as a cardiac signal which then responds by consequently pausing the cardiac rhythm of the patient and could lead to fainting. For ICDs, the cell phone signal could be mistaken for ventricular tachyarrhythmia and lead to a painful shock as the ICD is programmed to respond to what it thinks is abnormal heart rhythm.

Also, high electric fields such as those beneath high voltage power lines could induce similar behavior if the implants are set to configurations which lower their EMI susceptibility.

Pacemaker ICD Diagram

Pacemaker ICD Diagram


Electromagnetic Fields Linked To Pain in UTD Study

A very recent paper came out from my engineering school (The University of Texas at Dallas) that deals with a very controversial subject about whether EMFs can be sensed as tangible pain by certain individuals. An abstract or overview of the paper can be found here:

Study Uncovers How Electromagnetic Fields Amplify Pain in Amputees

The paper that was just published in January of 2016 is available here:

Electromagnetic Fields EMFs Induce Pain in Amputees

When I get some time, I will summarize the paper as it is highly technical and if possible, interview the professor for more details. Keep in mind that this study specifically covered amputees with relatively high levels of RF that you find fairly close to cell towers. (in mW/cm^2 millWatts / centimeters squared) and may not be applicable to what is found in typical residences.