Electromagnetic Field (EMF) Meters
Most paranormal investigators have heard of 'EMF' meters. They may have seen them being used on TV Ghosthunting programmes. They may already have them in their paranormal investigation kit. Many may not be aware of the reasons they are used or the way in which they work.
The first mistake many make is calling them EMF meters. In fact an EMF is totally different physical force - any good Physics book will tell you that an EMF is an Electro Motive Force and is in reality the force that causes electrons to flow through an electrical circuit and thus produces an electrical current. Perhaps we should refer to these meters as Magnetometers, Magnetic Flux Density meters, or even Electromagnetic radiation meters. However, the term EMF meter has now become almost universally accepted by Paranormal Investigators and even some equipment manufacturers so for this article at least we will continue to use the term EMF meter and Electromagnetic Fields - EMF's.
In the Beginning
Since the early 1980\'s paranormal investigators have become increasingly interested in various types of electromagnetism. This followed from the work of a number of researchers, but most notably Professor Michael Persinger at The Laurentian University in Canada. Working with others he conducted many experiments that suggested that when parts of the brain was exposed to electromagnetic fields of varying intensity and duration subjects reported experiences that were similar to those experiences associated with reported paranormal activity. He concluded that the source for these EMF\'s were both natural in the form of variations within the Earth's geomagnetism or interactions with solar radiation or manmade from sources that included electrical wiring and appliances or a combination and interaction of both types of source.
Later, he was able to recreate in his lab similar variations in EMF and apply those to the brains of test subjects many of whom reported experiences that were similar to the experiences reported by witnesses in alleged paranormal cases.
Logically, if investigators could use their own EMF meters and locate unusual or unexpected electromagnetic fields at a site being investigated they may be a little closer to determining a probable cause for some of the activity being reported.
Unfortunately, many investigators did not fully read the research or chose to simply ignore the parts of it they did not agree with. In time, the sound logic of looking for and measuring EMF became diluted and lost. EMF meters became Ghost Detectors.
Others came forward with their own versions of why an EMF meter was a useful tool for paranormal investigation - " Ghosts emit EMF's or distort the Earth's natural electromagnetism. Ghosts use the electricity supply to obtain energy that allows them to manifest, this cause the EMF to change and this can be measured" There are many variations on these themes and many books have earnestly declared that using an EMF meter will allow the investigator to detect the energy or presence of a ghost or spirit.
To date there is simply no evidence that ghosts or other forms of paranormal activity can emit or give off an EMF. They also do not have any proven ability to use EMF from any man made or natural sources.
A lot of research has been undertaken that does strongly suggest that when some people are exposed to a powerful EMF or a less powerful but varying EMF they may report sensations that they may believe are paranormal in origin. These effects include a sense of presence, a sense of touch, anxiety, unease, fear, nausea and even an 'Out of Body' sensation.
Exposure to electromagnetic fields when they are applied to the brain - or more accurately particular regions of the brain (the temporal lobes) can cause certain individuals to misinterpret the extra information from the EMF's. The resulting physical or sensory changes may be perceived as paranormal in origin by some people and may be the explanation in some cases of the real cause of the experiences.
Paranormal Investigators might therefore wish to measure the electromagnetism that is present at an investigation site with interest. They should note the intensity of the EMF, they should record the variations of the EMF and they should try and locate the sources of any EMF. This information may provide them with useful information that may help them determine the true nature of the experiences that are reported to them.
As mentioned earlier, electromagnetic fields can have natural and man-made sources.
EMF\'s are actually made up from two parts, a static electric field that is always present whenever any electrical charge is present or when an electric cable or appliance is connected to the supply - even if it is turned off, and a magnetic field that is created when the electricity is flowing such as in a lightning bolt or when an electrical appliance is turned on. The two components - the Electrostatic component and the Magnetic component make up the Electromagnetic field that is found around every electrical appliance or cable and is universally present within the Earth itself.
Natural sources of electromagnetism are often referred to as Extremely Low Frequency EMF\'s. These \'Geomagnetic Fields\' and are normally only measured by expensive and specialist equipment that are rarely to be found in a paranormal investigators kit. Geomagnetic fields are typically very low in frequency 0 - 10Hz.
In certain situations these low frequency Geomagnetic fields may impinge themselves upon and directly affect the man made electricity supply generated EMF.
Higher frequency sources typically those above 1kHz (1,000Hz) are to found in fluorescent lights and visual displays. These are capable of being measured by many readily available EMF meters although the actual value will normally be very different from the displayed value as the meter is calibrated or weighted for the much lower electricity supply frequency of 50 or 60Hz.
Most paranormal investigators use an AC EMF meter of a type that is designed to measure frequencies around 50Hz or 60Hz, which are the domestic electricity supply frequencies for the UK and the USA. Typically they will also measure EMF at frequencies above and below this calibration point although often with a greatly a reduced accuracy and sensitivity as the frequency moves further from the 50/60Hz optimum.
Unless one is using one of the more expensive meters that measure both components of the Electromagnetic Field most EMF meters costing less than £100 measure only the magnetic component of the field. The measurement is normally given in units of magnetic field strength - milli Gauss or micro Tesla, although often known as \'EMF meters\' they are in fact only Magnetic Field Meters. It is worth pointing out that although many EMF meters provide their measurements in milli Gauss (mG) the S.I. unit and thus the preferred unit of measurement for scientists and lab use is the Tesla, typically micro Tesla (uT). There are also many other units used in the measurement of EMF including the Henry and the Weber although these are rarely found on commercially available meters.
Some meters are available that can also measure the electric field component, the measurement being expressed in Volts/metre. These meters usually allow the user to switch between measurement of the Magnetic Field and measurement of the Electric Field or to take a reading of both fields combined together.
Electromagnetic Fields are normally directional, surrounding the source such as a cable or appliance. The primary field strength is dependent upon the direction of current flow. The field strength also diminishes as the distance from the source is increased, for ease of visualisation they may be likened to the ripples produced when a single pebble is dropped into a pond.
The Electromagnetic Fields from several sources can interact with one other similar to the effect seen when two or more pebbles are dropped into the pond. This leads to areas where the strength may be much higher or significantly lower than would be expected from a single source.
To obtain the maximum accuracy for ones measurements it is important that the actual sensor within the EMF meter corresponds to the direction of maximum field strength at any given location. If it does not then the user risks making measurements that may be much lower than the true field strength.
One solution to this problem would be to use a meter that has 3 sensors each at right angles to the others - this arrangement is known as the X-axis, Y-axis and Z-axis. By then combining the information from all three sensors mathematically inside the meter the display then shows a much more representative measurement for the field strength.
Single axis meters are available and are often preferred by investigators as they are generally much cheaper than 3-axis models and more readily available.
A single axis meter needs to be used with care. By carefully moving the meter around when making the measurement it is possible to discover the orientation of the field at a given location and then correctly align the meter\'s sensor with it to obtain the most accurate measurements.
Limitations for Use
There are a number of considerations that must be made when making any measurements in order that the subsequent data is as accurate and reliable as possible.
Obviously the first of these is to become fully conversant with the instruction supplied by the manufacturer. These instructions should also tell you the technical specifications of the device - the measuring range, frequency and accuracy are important pieces of information. Be aware of any limitations placed on the use or positioning of the device - if it is to be used near other items of equipment this may affect the subsequent data.
Normally the meter is measuring only the magnetic field that is generated when electricity is flowing through the wiring and the electronic circuits of the appliance.
If you have a meter that can measure electric fields you will find that they are present even if an appliance is turned off and that their value doesn't change as the appliance is turned on and off.
Almost without exception EMF meters used by paranormal investigators are designed for measuring EMF\'s caused by the domestic electricity supply. This is either 50Hz in the UK or 60Hz in the USA. That means that the meter is designed to be most accurate when measuring EMF\'s within that range of frequencies. Just about every building has an electricity supply or is located close to the electricity supply network of over ground and underground cables.
Most buildings have a number of electrical appliances. All of which generate an EMF that will be registered by an EMF meter. Depending upon a number of factors such as the distance from the appliance or the wiring, the power being consumed by the appliance and the type of appliance you may expect to see EMF readings from 0.1 milli Gauss (mG) to more than 100mG.
For example a TV set on standby may give a reading of less than 1mG at 30cm but over 50mG when it is turned on. A bedside clock radio can give you a surprisingly high reading of around 100mG at 20-30cm!
Many types of meter are described as 'Frequency Weighted\' or Frequency Calibrated. These do not give a simple measure of the field strength but instead their measurements are proportional to the frequency of the field. Instead of the actual strength of the EMF being shown the meter actually indicates the amount of energy the field is carrying - as the frequency of the EM emission increases so does the energy it carries.
The Alpha Labs TriField is just such a meter. An actual EMF of 3mG at a frequency of 60Hz will be shown as 3mG which is the true value. However if the EMF frequency is then increased to 120Hz the same strength field will now be shown as 6mG on the scale.
Some may ask "What is the point of making any measurements at all if the meter isn't even giving me the correct information?" In short there is a lot to be gained by continuing to make the measurements. For a start most of the EMF encountered within most locations is at the same frequency as the electricity supply and so the meter will be giving an accurate measurement of the EMF levels.
Secondly and more perhaps more importantly, much of the existing research into EMF\'s and reported paranormal phenomena is concentrated on it's effects on the human brain and body so a measurement indicating the 'power' from the EMF is probably more useful to the investigator than would a measurement of the actual field strength.
There are EMF meters available that give a flat Frequency response and within the limits of their designed frequency response they will give a more precise measure of the actual field strength present. With few exceptions they are more expensive and more suited to making measurements in the laboratory environment. Besides unless one is using a very expensive type of meter that has the ability to measure not only the EMF strength but also the frequency this information is generally of little additional benefit to the investigator.
It is important to understand that the meter will register changes in the EMF levels as you move around a location. Even if you keep the meter static in one position any changes in the flow of electricity (current) nearby will cause changes to register on your EMF meter.
This is quite normal and should be expected. You may not immediately see an obvious cause of the changing EMF or come across areas where the EMF seems unusually high. Often wires can be hidden inside walls and other structures. Domestic water pipes are also used as part of the buildings Earth (Ground) protection and electrical currents will flow through them causing EMF\'s to be formed around the pipe or wire.
Hidden metal structures can also hold or even generate an electric charge - this affect may vary depending upon the weather or the humidity. If this static electric charge then leaks to Earth you may well see a fluctuation in the EMF take place.
Natural changes in the Earth\'s electromagnetic field such as during thunderstorms, increased solar activity or even seismic activity can also induce electricity to flow in conductive man made and natural structures including wiring and appliances. This flow of electricity will produce a corresponding electromagnetic field that may be detected and measured by your EMF meter.
Positioning your meter prior to making any measurements needs to take these factors into consideration and you should avoid whenever possible positions close to known cables, appliances or metallic objects as they may cause erroneous readings.
Other investigation equipment you may be using such as radios or computers will also generate EMF\'s around them and these too can affect the reliability of your EMF measurements.
Some types of meter also measure the electric field and they need some additional special considerations - the human body generates a weak electric field and this is detectable by some of the meters such as the TriField Natural EM meter. If you position it too close to a person - normally less than about 8ft, it is likely that it will detect that persons electric field and register a reading. For that reason this type of meter should never be used handheld.
Measuring equipment can also malfunction or the batteries can run down causing unexpected readings to be seen. By testing the meter before the investigation and also afterwards you can eliminate some of these errors. Comparing a suspect meter with another similar meter is also a useful way to see if it may be faulty.
The majority of EMF meters used in paranormal investigation require the user to manually read a display - this may be either analogue such as a needle on a dial, or digital. Regardless of the display, it is important to note and record the EMF reading regularly - unless you are using a meter that can be linked to a PC then a minimum frequency of observation should be once every 5 - 10 minutes and more frequently if the level is continually changing. This can be tedious but it is important if one is to obtain a useful set of data.
One quick solution is to set up a camcorder to video the meter display - keep the camcorder at least 8 feet away so it will not adversely affect the readings too much and use the zoom to get a close up on the display.
The time that every measurement is taken is also important so that any unusual activity can be checked to against the EMF value at that time. Camcorders fortunately have internal clocks on all recent models.
If possible you may make some \'control\' measurements by turning off all the electrical power at the master switch for a period - at least 20 minutes is suggested.
All EMF meters are battery powered and if you are using a camcorder 20 minutes is normally within the capability of most machines. You should expect the EMF levels to fall away to almost Zero but that may not be the case at some locations. Neighbours using power or nearby power lines could still cause the meter to show a reading.
In all cases the information needs to be properly recorded for future analysis along with the location, the date and the time it was obtained.
There are some EMF meters available that have the ability to record the measurements to an internal memory and after a period of time this information can be downloaded to a PC. Others can be linked directly to a PC for real-time EMF measurement and logging. Currently these meters are expensive and rare and for the most part still unlikely to be seen in use by many paranormal investigators.
A Special EMF Meter
One further type of specialised meter that is available to the investigator is the Tri-Field Natural EM meter. This unique device measures fluctuations in both naturally occurring and man-made fields.
Most meters simply measure the amount of electromagnetism that is present. The Natural EM TriField meter only shows the amount by which the levels of EMF change - thus if they are stable it will register Zero. If the field then changes by 10mG then it will show a reading of 10mG before returning to Zero as the new value is reached.
Some of the research has shown the importance of rapidly fluctuating EMF\'s - being perhaps more important that just the amplitude of the field alone in causing some peoples brains to register and unusual experience that they may subsequently interpret as being paranormal in origin.
The Natural EM Tri-Field can obtain measurements of changes within magnetic fields and electric fields and show the result separately or as a SUM of both together. In addition it can also measure Microwave and radio frequency emissions. The TriField as its name suggests is a 3-axis meter and has 3 sensors for magnetic measurements and 3 sensors for electric measurements.
The Tri-Field has for some years been a 'standard' in many American investigators kits, but it has until recently been quite difficult to obtain over here in the UK.
The limitations of the Natural EM TriField meter have been mentioned briefly above. They are extremely sensitive items of equipment and will respond to any movement during use - they can easily detect the movement of the meter through the Earth\'s magnetic field and they can also detect the small electric field that people create. Thus in use they need to be kept in a static position and well away from people. The makers claim that they can detect a human more than 6ft away even through a wall.
Whilst it may be tempting to use the meter in the 'SUM' mode most of the time - in reality it's not a wise choice. All the operating care associated with the 'ELECTRIC' mode still apply and if the meter does show an interesting measurement you won't know without further studies if the cause was Electric or Magnetic. SUM mode is fine for a 'Quick Overview' of a location but for detailed measurements it is best to stick to either MAGNETIC or ELECTRIC Mode depending on your particular investigation requirements.
A brief word of caution: The Natural EM TriField meter should not be confused with several other models also called TriField Meters and looking very similar. These are 3-axis EMF meters that measure the amount of EMF in the conventional way and do not respond to the rate of change of the field strength.
Interpreting the Results
EMF meters have become almost an essential tool for the modern paranormal investigator. Like all equipment designed to collect information they need to be used with care and the information they provide needs to be used in context as part of the overall investigation. They are not Ghost Detectors. Some of the most promising research into the reasons why some people may have paranormal experiences lies in this area of study and it is area worthy of future exploration.
This article is intended to act as a guide to those seeking information prior to choosing and using such a tool. For those seeking more information they are advised to conduct their own research and there is a multitude of useful sites on the internet that deal with every aspect of EMF.
If possible the investigator should try to obtain several EMF meters so that they may be positioned at several points within a venue to more easily show unusual areas of EMF and also to permit a more reliable baseline for the whole location to be obtained. Simply wandering about at a location looking for areas of high readings is not a good method of conducting any investigation. The measurements would have no context.
It is important that a set of baseline values are established for each location you plan to make measurements of. One method of doing this is to simply place the meter at the chosen location for at least 15 minutes making a note of the reading every minute. By averaging these measurements you will have a \'15 minute\' average to compare any subsequent values against. This needs to be done for each location but ultimately is worth the effort as subsequent data will be more valid in terms of any unexpected variations from the baseline value.
If unusual values are encountered it is important to try and establish a cause, not simply accept it is paranormal. With EMF the most likely cause of unusual values will always be man made. Electrical appliances, hidden cables, appliances turning themselves on or off are all good causes for sudden EMF increases or decreases. The cause may be less obvious, the meter will respond to surges within the electricity supply. These may be at a distribution box or substation sometimes more than 100 metres away. Vehicles, electric trains and even static electricity from clothing can all cause an EMF meter to give unexpected readings.
Your EMF meter will also respond to naturally occurring sources of EMF although it does not measure them directly. Thunderstorms, even when they are many miles away can create surges in the electricity supply that will de detected by the TriField meter. Local storm activity can also induce surges within metal objects or wiring that is not even connected to the electricity supply network.
There are many potential causes for the unusual values you may sometimes see on your EMF meter and it is only with careful observation, sound measurements and a good understanding of the way in which EMF's behave that you will be able to make an informed assessment of the causes for any unexpected measurements you may see.
Article courtesy of: Parascience