MAGNETIC, ELECTRIC, RADIO AND MICROWAVE DETECTOR

Measure high ELECTRIC fields around cell phones, microwave ovens (check for leaks, door sealing, etc.), and CB radio transmitters, computer monitors, TV's, fluorescent lights, improperly grounded electrical equipment, and electric blankets (especially if the AC plug polarity is reversed) - even when in the OFF position if plugged in!

The Magnetic, Electric, Radio and Microwave Detector (M.E.R.M) uses a continuous sampling analog readout. Get fast & accurate measurements of high, artificial electromagnetic fields around clock radios, computers, electric appliances, running cars (especially near front floorboard, dashboard, and radio). Calibrated to 60Hz (North America). Detect and measure RADIO/MICROWAVE fields around cell phones, microwave ovens (check for leaks, door sealing, etc.), and CB radio transmitters. A reading of .2 mW/cm2 at a distance of six feet suggests a leaking microwave door seal.

The radio/microwave setting can detect up to three billion Hz (3 GHz), which lets you gauge radio-wave power, CB and cellular phone equipment, and many types of radars.

Most meters priced under $500.00 read only low-frequency magnetic fields and only in one direction (not true magnitude). The magnetic section of the M.E.R.M Detector has three field-detecting coils pointing in the X, Y, and Z directions. A circuit amplifies these signals and gives them the proper frequency-weighting (sensitivity increase linearly from 30 Hz to 500 Hz, with some residual sensitivity up to 100 MHz). A unique network combines the three coil outputs nonlinearity to approximate a true magnitude. The meter is sensitive from 0.2 to 100 milligauss full scale at 60 Hz (or 0.1 to 50 milligauss full scale at 120 Hz, etc.) with a resolution of 0.2 milligauss in the sensitive range. Accuracy is + / - 20% at mid-range.

Depending on the position of the knob, the meter detects either frequency-weighted magnetic fields (two separate scales) or frequency-weighted electric fields in the ELF and VLF range. The device has significant sensitivity at 100,000 Hz, well past the 17,000 Hz horizontal scan of video displays.

If you hold the meter in the center of a room and tip it to various angles, the magnetic reading will stay approximately the same regardless of which way you tip or rotate it. The electric reading is similar, although the presence of your body alters the actual electric field, so readings will vary more. The radio / microwave setting reads the full power of radio waves when the meter is pointed toward the source.

USING THE M.E.R.M DETECTOR:

A knob on the front has six positions: OFF, BATTERY TEST, two MAGNETIC field sensitivities (0.5-100 milligauss at 60 Hz, and 0.2-3 milligauss at 60 Hz, the second sensitivity to measure weak fields more accurately), ELECTRIC field and RADIO/MICROWAVE power density. The meter face is analog (needle type). A needle reading of one-third of full scale corresponds to either 3 milligauss (or 0.6 milligauss) @ 60 Hz, 3 kilovolts/meter @ 60 Hz, or 0.04 mW/cm2 respectively in the magnetic, electric, and radio/microwave field settings. Average magnetic field strength in North American homes and offices is 1-3 milligauss, so the meter is labeled "HIGH" above these levels.

MAGNETIC FIELD DETECTION:

In homes or offices, some areas are "hot" spots with readings in the HIGH range. Most often, this is caused by magnetic fields, which come largely from unpaired internal wiring. (Contrary to popular belief, power transmission lines and transformers do not generally contribute as much magnetic field as does internal wiring.) Other magnetic sources include video displays, motorized clocks and other equipment, electric blankets and heaters, fluorescent lights and light dimmers, and the transformers that are inside consumer devices. Much of the total field strength is from frequencies that are harmonics or multiples of 60 Hz (120 Hz, 180 Hz, etc.) and 17,000 Hz of video displays. Cars (especially near the front floorboard of electronic ignition cars) and motorcycles have fairly strong fields that are at frequencies higher than 60 Hz. Magnetic field is difficult to shield, but sheet steel is somewhat effective.

ELECTRIC FIELD DETECTION:

A few areas in most homes read HIGH in the electric field setting. These include areas near improperly grounded equipment, the front of video screens, and fluorescent lights. Most of these fields can be easily shielded using a grounded metal screen or foil; VDT screens of this type are readily available. You can greatly reduce the strength of an electric field just by placing your hand in front of the source. This effect can be seen using the M.E.R.M Detector.

MICROWAVE DETECTION:

Occasionally, certain areas read HIGH in the radio/microwave setting. These include door seals around microwave ovens and the back of the microwave oven, pagers, wireless phones, and cellular phones (but not regular radio phones, which are very low-power). Radio/microwaves can be shielded in the same way as electric fields, although the lower frequency radio waves are not shielded by your hand as easily as microwaves are. (Metal screens will shield both.) In the United States, radars and FM transmitters can legally expose residents to moderately high power levels (as high as 10 mW/cm2 briefly or .57 mW/cm2 near cellular towers).

REDUCING FIELD EXPOSURE:

Some equipment is sensitive to magnetic fields (ie, a high resolution color monitor may not function properly above 30 milligauss). By seeing "hot" spots in your home and office, you can move equipment or furniture to reduce exposure. If a room has a "hot" spot, fields are generally much weaker elsewhere in that same room.