If your house is already haunted by mundane spooks, be prepared for non-UFO alarms. Parapsychologists have found that compasses and other electrical devices respond when a ghost is present. If you live in a large city, there may be so many electrical interferences in your building that the UFO detector will be useless. For example, the elevator could set it off. Readers who understand electronics can build a much more sensitive magnetic field distortion detector with transistors, resistors, and capacitors.
Several designs are available.
John Keel is a long-time student of the strange and unknown and the author of many books and screenplays. He writes a bi-monthly column for FATE Magazine. Email the Webmaster with any experiences, comments or pictures.