AlphaLab Natural Electromagnetic (EM) Meter Model NEM2
To use the meter, turn the knob to Battery Test. The needle should be on or to the right of the diagonal line which is itself to the right of the words "Batt Test" on the meter scale. If the needle reads left of that line, replace by unscrewing the four back screws. A regular 9 volt battery will last for about 10 hours of testing; an alkaline will last for 50. The AC adapter can also be used. The adapter plug disconnects the battery, so the adapter does not charge the battery. An adapter is included, but any 11-20 VDC center negative 2.1 mm adapter can be used. Accidentally using the wrong polarity adapter will not damage the meter.
On MAGNETIC, the meter reads any change in the magnetic field caused by rotating the meter in the Earth's magnetic field, by a moving magnetic object, or by DC currents carried by wires or the atmosphere. The Earth's field strength is about 50 microteslas (500 milligauss), so rotating the meter from north to south rapidly (within a 0.5 second interval) causes a momentary reading of about 100 (a change from -50 to +50). If subsequently held still, the needle will settle back to zero. For the best readings of transient fields, the meter should be placed on a stationary platform because of sensitivity to slight rotations while hand-held. The external coil, when plugged in, will bypass the internal coil and multiply the magnetic sensitivity by 10, so the scale will be in milligauss.
Though the body produces very little magnetic field, the electric field is strong enough to be measured. Turn the knob to ELECTRIC and multiply the reading by 10 to get units of V/m; thus a momentary needle peak at full scale means the field changed by 1000 V/m. During a thunderstorm, the electric field will fluctuate indoors by as much as 100 V/m. At other times, the fluctuation is less than 3 V/m, so that indoor transient phenomena are easier to detect during calm weather. Set the meter upright on a stationary metal surface for greatest sensitivity.
On SUM, the meter will add any changes in the radio/microwave field to any changes in the magnetic field, so that if either field increases or decreases, the needle will rise above zero. Using the AC adaptor with the meter on SUM is recommended for detecting unusual aerial phenomena. It can be left on continuously.
RADIO/MICROWAVE directly reads radio waves from 100 KHz to 3 GHz, and can detect fairly weak localized radio sources if you hold the top of the meter close to the source. In most areas this always reads zero. (It can also check a microwave oven for leakage. If you turn the oven on and stand six feet away, the meter should read less than half scale, or 0.2 milliwatts per square centimeter, for a properly functioning oven. If it reads higher than 0.2, have the door seal repaired.)
The side knob controls the tone threshold. The tone sounds only if the needle deflection is higher than the level set on the knob. The tone won't sound at all if the knob is turned all the way counterclockwise.
