Since the airing of "Ghost Hunters" on the Sci-Fi Channel, the sales of EMF meters has gone through the roof!
The problem is that many people expect them to "automatically" detect ghosts but in all reality, EMF meters should be used to help rule out natural causes in the environment.
Here is an article that I found would helpful for newcomers to EMF meters. This article comes from About.com's Paranormal section.
Tips for Measuring Magnetic Fields at Haunt Sites
Friday, November 02, 2007
After discussing the relationship between haunting experiences and magnetic fields in our previous blog posts, we now present some useful tips for paranormal enthusiasts on measuring magnetic fields, both geomagnetic and electromagnetic, at haunt sites during field investigations.
1.) Always take note of the area around the spot you are measuring to make sure that there are no electronics, appliances, power lines or generators, and wiring nearby that may be a natural cause for any magnetic fields you detect. This will be better ensure that you may be getting an anomalous reading, and not a false one.
It is vitally important to recognize that although it appears that magnetic fields may be tied in some way to apparitions and haunting phenomena, this does not necessarily mean that the presence of fields at haunt sites are due to ghosts. Many less-experienced investigators have immediately jumped to this conclusion, and one can see that it is generally not correct when one realizes that there are many sources in non-haunted locations that can generate these fields by conventional means. These same sources may also be found in haunt sites.
2.) Be sure to take baseline readings of the haunt site to determine the average magnetic field strength of the site. It can be helpful to compare readings taken from areas where ghostly phenomena has been reported with reading taken from nearby areas where no phenomena has been reported (“control” areas).
It is useful to establish a baseline magnetic reading that can be compared to the magnetic field readings at the haunt site, which may help determine just how different the two are from each other (a basic indication of how “anomalous” the magnetic fields at the haunt site are). Measurements should first be recorded throughout the haunt site to determine the average magnetic field strength of the site, as well as locate any areas where there might be natural irregularities in the field due to power generators, power lines entering the building, and/or a large amount of electronics, appliances, and/or electrical wiring gathered in one room.
This practice will also help in accomplishing the goal in Tip #1. Houran and Brugger (2000) have suggested that measurements at haunt sites should also be compared to those taken in a “control” site where no haunting phenomena have been reported. This can help to establish that the measurements from haunt sites are anomalous, and not just part of the regular background fields of the site. As noted above, there are several conventional sources at non-haunt sites that may produce large magnetic fields from time-to-time, and some of these same sources may also be found in haunt sites.
If the measurements from the haunt site and the control site are close to each other in strength when they are compared, then this may hint at these conventional sources being involved, and the readings at the haunt site not being particularly anomalous.
3.) Investigators may want to try to detect changes in the magnetic field over time by taking repeated measurements in different areas of a room, and/or different areas of the haunt site to see if there is any potential sign of a gradual increase or decrease across the haunt site.
A number of field investigations reported in the parapsychological literature are beginning to indicate that it is not the absolute strength or intensity of the magnetic field at the haunt site that may be important, but rather the way that the field changes over time. In at least two of the haunts investigated by noted parapsychologist William Roll (reported in Roll & Persinger, pp. 156 – 157), the strength of the magnetic fields were noted to either be gradually increasing or decreasing as one moved from one side of the haunt site to the other, suggesting that the field was changing throughout the site.
In the course of investigating haunt reports at historic Hampton Court Palace in England, Wiseman et al. (2002, 2003) noted in a statistical comparison that the magnetic field changes in areas of the palace where haunting phenomena had been reported were significantly different from the field changes in areas where no phenomena were reported. They also found in another statistical comparison that the number of unusual experiences reported by tourists visiting the Palace was also related in some way to the magnetic field changes at the site.
Braithwaite and associates have taken several measurements in a specific bedroom at historic Muncaster Castle in England (Braithwaite, 2004; Braithwaite et al., 2004). People sleeping in the bed found in that bedroom have reported hearing voices at night that sound like children crying, and measurements were taken in the area around the pillow of the bed and later compared to control measurements taken towards the center of the room, where the voices apparently came from. Notable changes in magnetic field strength were noted over this very short distance (roughly a few meters), suggesting magnetic field changes across the space of a single room. Most recently, Terhune et al. (2007) found suggestive differences when statistically comparing the magnetic field changes in areas where haunt phenomena were reported to control areas where no phenomena occurred.
Similarly, the magnetic fields applied to the brain that Persinger and his associates use to simulate haunt-related experiences (Persinger, 2001; Persinger & Koren, 2001; Persinger et al., 2000) are composed of complex patterns that can change the structure of the fields.
4.) Carefully log all magnetic readings and conditions, including specific locations where readings where taken, time that readings were taken, and the length of time that the magnetic field was present.
If a floor plan of the site(s) under investigation is available, use copies of this floor plan to record your readings. Otherwise, it might be beneficial to draft your own floor plan of the site(s), time and resources permitting. If one hopes to have their results taken seriously, it is vital to have a complete record or log of the investigation, particularly of all measurements made.
Human memory alone is unreliable because it is subject to bias and error. Having a record may also help to reveal possible patterns in the activity at the haunt site that may hint at a possible natural source for it (e.g., some EMFs in homes and buildings may sometimes change at regular intervals when certain equipment or appliances, such as air conditioners, refrigerators, etc., turn on and off).
Although it is not meant to be comprehensive, we hope that this primer provides a starting basis for those paranormal enthusiasts who wish to take their approach to haunting investigations a step further.
-Bryan Williams, University of New Mexico
-Annalisa Ventola, Public Parapsychology
-Mike Wilson, Psi Society
Braithwaite, J. J. (2004). Magnetic variances associated with ‘haunt-type’ experiences: A comparison using time-synchronized baseline measurements. European Journal of Parapsychology, 19, 3 – 28.
Braithwaite, J. J., Perez-Aquino, K., & Townsend, M. (2004). In search of magnetic anomalies associated with haunt-type experiences: Pulses and patterns in dual time-synchronized measurements. Journal of Parapsychology, 68, 255 – 288.
Houran, J., & Brugger, P. (2000). The need for independent control sites: A methodological suggestion with special reference to haunting and poltergeist field research. European Journal of Parapsychology, 15, 30 – 45.
Persinger, M. A. (2001). The neuropsychiatry of paranormal experiences. Journal of Neuropsychiatry and the Clinical Neurosciences, 13, 515 – 524.
Persinger, M. A., & Koren, S. A. (2001). Predicting the characteristics of haunt phenomena from geomagnetic factors and brain sensitivity: Evidence from field and experimental studies. In J. Houran & R. Lange (Eds.) Hauntings and Poltergeists: Multidisciplinary Perspectives (pp. 179 – 194). Jefferson, NC: McFarland & Company, Inc.
Persinger, M. A., Tiller, S. G., & Koren, S. A. (2000). Experimental simulation of a haunt experience and elicitation of paroxysmal electroencephalographic activity by transcerebral complex magnetic fields: Induction of a synthetic “ghost”? Perceptual and Motor Skills, 90, 659 – 674.
Roll, W. G., & Persinger, M. A. (2001). Investigations of poltergeists and haunts: A review and interpretation. In J. Houran & R. Lange (Eds.) Hauntings and Poltergeists: Multidisciplinary Perspectives (pp. 123 – 163). Jefferson, NC: McFarland & Company, Inc.
Terhune, D. B., Ventola, A., & Houran, J. (2007). An analysis of contextual variables and the incidence of photographic anomalies at an alleged haunt and a control site. Journal of Scientific Exploration, 21, 99 – 120.
Wiseman, R., Watt, C., Greening, E., Stevens, P., & O’Keeffe, C. (2002). An investigation into the alleged haunting of Hampton Court Palace: Psychological variables and magnetic fields. Journal of Parapsychology, 66, 387 – 408.
Wiseman, R., Watt, C., Stevens, P., Greening, E., & O’Keeffe, C. (2003). An investigation into alleged ‘hauntings.’ British Journal of Psychology, 94, 195 – 211.