[QUOTE=Turtle;195740]Hey Frank! Check this out;
This device looks much simpler to build and use than the field mill. >>
The disruption of radio propagation prior to major earthquakes has been noted as far back as the 1960s. The APM device will be influenced by propagation disruptions that are hundreds of miles away and they can be in any direction. A field mill will detect the differential potential in-line with the direction of the vane aperture, the local potential. A field mill sitting vertically will detect the difference between where the device is sitting and the atmosphere above it.
Below is an abstract of Friedemann Freund's work prepared by someone else.
IEEE Spectrum: Early Warning For Earthquakes
I was unable to download the full article from IEEE. Any IEEE members here?
