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Price: $195.00

    Field Strength Meter 100 KHz to 3 GHz

    The TriField Natural EM Meter was designed to do field measurements for special research. It detects changes in extremely weak static (DC or “natural”) electric and magnetic fields, and signals with both a tone and the movement of a needle-type gauge if either the electric or magnetic field changes from previous levels. A radio and microwave detector is included which reads radio frequency power density directly. Because man-made AC electric and magnetic fields are very common and could interfere with readings of static fields, the meter has been designed to be relatively insensitive to powerline fields. Normal construction materials don’t block magnetic fields, so the meter can be placed indoors and will work equally well, and due to the built-in tone, it can will sound the tone at whatever level of field the user sets. Model 1 operates on a standard 9-volt battery. One year warranty.


    The radio/microwave detector is sensitive from 20 MHz to 6 GHz and can detect strong or unusual atmospheric electrical activity. It can also detect leaky microwave ovens, cellular or portable phones, walkie-talkies and concealed surveillance bugs. Its minimum and maximum detectable signal strengths are 10 microwatt/cm2 and 1 milliwatt/cm2 respectively.


    The meter is sensitive to changes of as little as 0.5% of the strength of the Earth’s magnetic field, and the tone will sound whether the field increases or decreases. After the meter detects an event, when the magnetic field then becomes stable for more than about five seconds, the tone will stop and the needle will return to zero. The meter will remain at rest until the field changes again. The threshold level (squelch level) of the tone is adjustable. The user determines the amount of change in the magnetic field required to sound the tone. If the field changes by the threshold amount, the tone will come on at a low pitch. If the amount of change is larger, the tone’s pitch will be higher.

    The Natural EM Meter can detect geomagnetic storms caused by unusual solar activity interacting with the ionosphere (which results in rapid changes of up to 10% in the Earth’s magnetic field), as well as the electrical activity of ordinary thunderstorms. It will signal the movement of any distant, strong magnetic sources in the sky.


    When the dial is set to ELECTRIC, the meter is sensitive to electric fields as weak as 3 V/m (volts per meter). Indoors, electric fields typically fluctuate 1 or 2 V/m. By setting the minimum sensitivity to change at 3 V/m, we have designed the meter to disregard this “background noise”. A 3V/m field is so feeble that if a 10’x10’x10' room were filled with a field of this strength, it would contain the total amount of energy equivalent to that required to lift a single grain of table salt 1/50th of an inch.


    The SUM setting in Model 1 adds together the electric and magnetic fields and detects if either field changes.