Walker EMF measuring instrument (C) Daniel Friedman EMF Measuring Equipment: Guide to Selecting & Using Electromagnetic Field Measurement Instruments for EMF ELF Surveys
     

  • ELECTROMAGNETIC FIELD EMF ELF DETECTION INSTRUMENTS - CONTENTS:Description & Evaluation of several low-cost EMF measurement instruments. Special tips for using individual electromagnetic field survey EMF or ELF measurement devices. Where and how to buy EMF measuring devices for DIY Electromagnetic field measurements and surveys
  • POST a QUESTION or READ FAQs about where to buy an EMF meter, comparisons of low cost devices and how to use them
  • REFERENCES

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

This article describes low-cost RF, EMF or ELF electromagnetic field survey measurement instruments useful for performing electromagnetic field (EMF) or electro-magnetic radiation EMR measurements either by engaging a professional or by consumers using low-cost instruments which measure EMF exposure levels in gauss or milligauss.

We review and make suggestions for using several low-cost EMF measurement devices to determine the instantaneous electromagnetic field exposure.

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Descriptions & Sources of Low-Cost MF ELF Measurement Instruments

Safeco EMF meter  (C) Daniel FriedmanSpecific ELF (extra low frequency) electromagnetic field (EMF) measurement tools (power lines, electrical wiring, appliances) are described and their sources listed in this article.

Before buying an EMF or RF test instrument, in order to make sure that the device you are buying is the right one for the hazard you are trying to measure, see EMF RF FIELD & FREQUENCY DEFINITIONS for a simple explanation of different types of radio frequency (RF) and electromagnetic frequency (EMF) types and where they are found.

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. This information is has not been sanctioned nor technically reviewed by the American Society of Home Inspectors nor the American Industrial Hygiene Association - AIHA. Use it at your own risk.

Below we provide comments, specifications, photos and descriptions of several of the many readily available EMF measuring instruments on the market today.

The devices listed just below are for low frequency EMF detection and measurement. For higher frequency RF or radio frequency detection and measurement, Radio Frequency RF Detection Meters.

TriField EMF Meter

TriField EMF MeterShown at left is the TriField® meter capable of measuring electromagnetic fields. This device sells for about $150.

The TriField EMF meter is produced by AlphaLab and measures both electrical field and magnetic field strength in the ELF and VLF ranges. This meter is reported to be sensitive to and to indicate more sources of EMF than some other devices.

The TriField meter can also measure microwave field strength.

Do not confuse microwave radiation, radio wave radiation, and Electromagnetic Field (EMF) radiation.

  • Electromagnetic Field radiation (EMF) generated by electrical power lines and also by residential electrical appliances is in the 50Hz or 60 Hz range (this is "low frequency").
  • Microwaves and cell phone towers and similar equipment are at the opposite (very high) end of the radio frequency spectrum, and generate electrical energy at frequencies at up to 3 Ghz (3 billion cycles per second).

The exposures and health effects of electromagnetic fields and the studies that examine them make critical distinctions between these different types of energy sources and frequencies.

F.W. Bell Model 4060 ELF Meter

FW Bell 4060 ELF Digital EMF MeterThe F.W. Bell Model 4060 ELF digital EMF Meter is a small hand-held instrument that like the Walker above, has been designed and calibrated to measure low level 50Hz or 60Hz electromagnetic fields generated by power lines, TV sets, video display terminals (VDT's), home appliances, industrial machinery, and similar devices.

This is a pocket-sized instrument that is lightweight and will easily fit into a shirt or jacket pocket.

The company describes the instrument as designed to detect magnetic fields radiated by T.V. sets, computer terminals, power lines, home appliances, machinery, electric blankets, etc.

F.W. Bell is located in Orlando, FL.

Reed Instrument EMF tester,Model 822A

The Reed EMF 822A EMF tester measures electromagnetic radiation levels from video terminals, fans, faulty wiring, power lines and other equipment. Here are some specifications:

  • 3-1/2 digit, 0.5" high LCD readout with over range indication
  • Range: 0.1 to 199.9 mG [Note that 1000 mG is 1 Gauss]
  • Frequency Bandwidth: 30 to 300 Hz
  • Accuracy: ±4% at 50/60 Hz (single axis)
  • Sampling Rate: 2.5X/second
  • Power Supply: Single 9V battery

Safeco™ analog EMF ELF EMR meter

Safeco EMF meter  (C) Daniel FriedmanUsed in its "C" or "ELF" range to screen an area for magnetic fields typically generated by power transmission lines, secondary lines, power transformers, and household wiring (Extremely Low Frequency, or ELF) our test instrument measures magnetic field strength across seven scales from .3 milligauss to 302 milligauss.

Used in its "A" or "VLF" range to screen an area for magnetic fields typically generated by televisions and computers (Very Low Frequency, or VLF) our test instrument measures from .12 microgauss to 8312 microgauss. 1000 microgauss = 1 milligauss = 80 milliamps per meter.

The accuracy of this instrument itself is +/- 5%, which is typical for portable, hand-held electronic devices. The instrument is calibrated by the manufacturer using a Holaday 3600 for ELF fields. That instrument is available for additional measurements if necessary.

Measurements of ELF (around 60 Hz) will be confounded if there is nearby VLF (such as from a TV or Computer). We attempt to discover and will record the presence of such devices if seen, but we cannot guarantee that there were no such devices operating in or around the property being examined at the time of our tests.

Generally such devices create a measurement problem only if they are within 15-20 feet of our instrument. We verify that a suspect high reading is not coming from a TV or computer by flipping from the "C" to "A" range - if the reading does not change significantly then there is VLF interference from a TV or Computer.

The Safe Meter™ is manufactured by Safe Computing CO., 368 Hillside Ave., Needham, MA 02194 800/222-3003.

The Walker Scientific ELF-50D™ Digital EMF field strength Meter

Walker EMF measuring instrument (C) Daniel FriedmanThe Walker Scientific ELF-50™ Digital EMF Meter is a portable handheld instrument designed and calibrated to measure low level 50Hz or 60Hz electromagnetic fields generated by power lines, TV sets, video display terminals (VDT's), home appliances, industrial machinery, and similar devices.

The low-range instrument setting measures field measurements from 1 to 20 milligauss.

This is the range in which most measurements are performed and it is the range within which current literature on this topic discusses possible health effects. The high-range instrument setting is used to measure fields from 10 milligauss to 20 gauss.

As with our analog instrument, the readings obtained with this device depend on the position with which it is held in the field being measured as well as the field strength.

The manufacturer provides a certificate of test and calibration certifying that the instrument has been tested to meet or exceed its published specifications. A copy of this certification is available for your inspection.

This instrument is manufactured by Walker Scientific, Inc., Rockdale St., Worcester, MA 01606 508-852-3674 / 853-3232 / 800-962-4638 / 508-856-9931 FAX.

How & Why to Make Your Own EMF Field Survey & Exposure Measurements

Instead of contacting us with a request to perform EMF Electromagnetic Field Strength measurements, in most cases it is more economical and convenient for a property owner to purchase their own instrument, making measurements under varying conditions. In this series of articles we describe how to make measurements using a consistent approach and using good documentation.

Following good procedure and using instruments properly are two steps towards making accurate, repeatable EMF measurements.

But because the signal transmission for RF sources such as radio, TV, or cell towers, the load on a power transmission line is not under control of an individual property owner, and because the EMF strength varies as the power transmission line load varies, it is important to have an idea of that condition as well when attempting to characterize EMF exposure at a specific location. In contrast, EMF measurements are quite accurate and repeatable at other EMF sources such as close to electrical appliances and service entry cables.

Where to Buy EMF Electromagnetic Field Exposure or Strength Monitoring/Measuring Equipment

At InspectApedia we do not sell anything. To do so would be a conflict of interest for this website. These devices are readily available from the manufacturers and product sources listed in this article and from many electrical equipment and home inspection equipment suppliers.

  • See Evaluation of Low-Cost EMF Instruments This article (above) describes several low-cost and reasonably accurate EMF measurement devices that are readily available.
  • See Radio Frequency RF Detection Meters This separate article describes several low-cost and accurate radio frequency or RF detection and measurement devices suitable for radio, TV, cellphone, microwave, and similar signals.

Portable Electromocardiography Instruments & Applications Research

Reader question: where can I find a portable device to measure the hunan cardiac electromagnetic field?

Greetings and PEACE! I'm doing a dissertation proposal concerning the human cardiac electromagnetic field. Heartmath Institute has done studies demonstrating that the field can be measure up to 12 ft. away. What I'm interested in is a portable device that could both detect the field as well as the changes caused by emotions at 5-10 ft. Any ideas? - J.S. 2/25/2014

Reply: Portable Electromocardiography research citations describe both static and portable approaches

J.S. that's beyond my expertise, and certainly the typical handheld EMF instruments are not suitable. One needs to know the EMF frequency range first (which any cardiology instrument maker knows), then the field strength. That would permit assessing instruments.

Here are some research citations of interest, as I'll bet one of these authors would be interested and can answer more directly. BTW I saw no evidence of actual scholarly research at the source you cited except a self citation:

  • The Electricity of Touch: Detection and Measurement of Cardiac Energy Exchange Between People by Rollin McCraty, Ph.D., Mike Atkinson, Dana Tomasino, B.A., and William A. Tiller, Ph.D.: http://www.heartmath.org/research/research-publications/electricity-of-touch.html
    in turn citing
  • Karl H. Pribram, ed. Brain and Values: Is a Biological Science of Values Possible. Mahwah, NJ: Lawrence Erlbaum Associates, Publishers, 1998: 359-379. The end of this paper includes quite a few citations, some of whom might discuss instrumentation, though most of the citations refer to psychology and the theraputic effects of touch.

Also see:

  • Lewis, Michael J. "Review of electromagnetic source investigations of the fetal heart." Medical engineering & physics 25.10 (2003): 801-810.

    Abstract: There is at present no reliable clinical technique for the assessment of cardiac electrophysiological activity in the fetus. There are two primary requirements of this type of monitoring:

    (i) sequential assessment of morphological and temporal parameters of cardiac electrical activity during advancing gestation, and

    (ii) description of the cardiac electrical activity in terms of an electrophysiologically realistic model. Fetal electrocardiography may be performed using maternal abdominal electrodes but this is only reliable prior to the 27th week of gestation.

    This is primarily because of the electrically insulating effects of the vernix caseosa and the existence of preferred conduction pathways between the fetal heart and maternal abdomen after this time. Fetal magnetocardiography is largely unaffected by these factors and so enables a reliable assessment of fetal electrocardiological activity throughout the second and third trimesters of pregnancy. This method can also be used to model fetal electrophysiological activity in terms of a current dipole or magnetic dipole.

    The vectorcardiogram is a plot of the dynamic change in dipole parameters during the cardiac cycle, allowing the study of growth-related or pathology-related electromagnetic changes in the heart. Fetal magnetocardiography and the fetal vectorcardiogram may thus provide important additions to current methods of antenatal monitoring.

While this Wikipedia entry suggests that you're on a futile quest, and that the instrumentation used is large, requires a special environment, and so hardly looks portable

The first MCG measurements were made by Baule and McFee[1] using two large coils placed over the chest, connected in opposition to cancel out the relatively large magnetic background. Heart signals were indeed seen, but were very noisy.

The next development was by David Cohen,[2] who used a magnetically shielded room to reduce the background, and a smaller coil with better electronics; the heart signals were now less noisy, allowing a magnetic map to be made, verifying the magnetic properties and source of the signal. However, the use of an inherently noisy coil detector discouraged widespread interest in the MCG.

The turning point came with the development of the sensitive detector called the SQUID (superconducting quantum interference device) by James Zimmerman.[3] The combination of this detector and Cohen's new shielded room at MIT allowed the MCG signal to be seen as clearly as the conventional electrocardiogram, and the publication of this result[4] marked the real beginning of magnetocardiography (as well as Biomagnetism generally).

Magnetocardiography is now used in various laboratories and clinics around the world, both for research on the normal human heart, and for clinical diagnosis.[5]
- Wikipedia, retrieved 2/25/2014

Despite the implications of that Wikipedia article's view, there are some citations for portable magnetocardiography:

  • Kandori, A., et al. "Development of semi-portable DC-SQUID magnetometer." Applied Superconductivity, IEEE Transactions on 5.2 (1995): 2474-2477.
  • Mhaskar, Rahul R., Svenja Knappe, and John Kitching. "Low-frequency characterization of MEMS-based portable atomic magnetometer." Frequency Control Symposium (FCS), 2010 IEEE International. IEEE, 2010.
  • Wyllie, R., et al. "Magnetocardiography with a modular spin-exchange relaxation-free atomic magnetometer array." Physics in medicine and biology 57.9 (2012): 2619.

    General scientific summary We present a four channel atomic magnetometer array. Each magnetometer channel consists of a rubidium atomic vapor cell, cell heaters, magnetic field coils, and all the required optics.

    Since each element of the array is independent and modular, the devices can be tilted or moved with respect to one another with spacing down to 4.5 cm. The noise in each magnetometer is dominated by the background magnetic noise in the magnetically shielded room in which the array is used.

    We have detected the magnetic field from the hearts of 13 adult human subjects with this setup, demonstrating the feasibility of our device for human biomagnetism. This work is progress towards our ultimate goal, which is to use our device to detect foetal heart signals, a clinically interesting application requiring very high magnetic sensitivity but relatively few sensors.
  • Wyllie, Robert, et al. "A multichannel portable SERF atomic magnetometer for biomagnetic measurement." APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts. Vol. 1. 2011.
  • Zhang, Yi, et al. "HTS SQUID gradiometer using substrate resonators operating in an unshielded environment-a portable MCG system." IEEE transactions on applied superconductivity 13.2 (2003): 389-392.
  • Zhao, Hui, et al. "Simultaneous fetal magnetocardiography and ultrasound/Doppler imaging." Biomedical Engineering, IEEE Transactions on 54.6 (2007): 1167-1171.

Zhang describes using a portable device in an unshielded environment - important for your question.

 

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