Set the sensor box (black) on the ground or at about the same level as the package, either 7 feet or 15 feet from where packages will be measured. Measure distance from the small black square printed on the top of the sensor box, to the nearest edge of the package. (The actual sensor is 1” in vertical altitude below the black square, so it’s near the bottom of the black box). With the sensor label pointing up, the arrow should point toward the package testing area. Avoid having any large steel objects within 5 feet of the sensor. You may want to use an AC adaptor instead of the battery. If so, use the jack on the side of the white display box. (It is 12V DC, center positive. For North American orders, and AC adaptor is included.) Remove any packages from the testing area.

The Earth field must now be “zeroed”. With the FINE and MEDIUM offset knobs set at zero, switch the MILLIGAUSS RANGE to 199.99, and then rotate the COARSE OFFSET until the display shows a slightly negative number. Then rotate the MEDIUM OFFSET knob until the display reads somewhere between –03.00 and zero. Then rotate the FINE OFFSET knob until the display reads near zero. If the display fluctuates up and down by more than a few counts, then the environment is magnetically noisy, and a new test site should be considered. Heavy equipment moving nearby will cause this fluctuation. In summary, point the sensor box arrow toward the shipment, and find a place to do the testing where there is not much magnetic interference. Then use the three offset knobs to get the display to read near zero. Once done, the display will not need to be readjusted unless you move the sensor box or if something that is magnetic moves.

Now, bring in the package to be tested in such a way that the nearest face of the package is 15 feet (4.5m) from the black square on the sensor box. The arrow should be pointing toward the package. Make sure the shipment can be rotated 360 °. The package need only be roughly on the same level as the sensor. If the meter reads more than “05.25” milligauss (0.00525 gauss), or more negative than “-05.25” anywhere during the 360 ° rotation of the shipment, it cannot be shipped by air, unless some alterations (demagnetizing, adding keeper bars, or reorienting the magnets inside the shipment) are done. Generally, the field from the shipment will be a simple “dipole”. That is, the field will be most positive when one face of the package is pointing to the sensor and will gradually go more negative as the package is rotated, reaching the most negative number 180 ° away. The negative and positive numbers are generally about the same magnitude.

If the shipment has a very low magnetic field, it need not be labeled as magnetic. This is a different test, done at 7 feet (2.1m) from the sensor. At 7 feet, if the shipment does not exceed 02.00 to –02.00 milligauss (0.002 gauss) anywhere along the 360 °, then magnetic labeling is not required, and it can be shipped without magnetic restrictions.

This meter can also be used to read the actual value of the magnetic field (in the direction of the long dimension of the meter) if all OFFSET controls are set to zero. Then in the 199.99 range, it can read up to (just under) 200 milligauss, and in the 1999.9 range it can read up to (just under) 2000 milligauss. In comparison, the Earth field is about 500 milligauss, which is generally in an unexpected angle: 20-60 ° downward of north.

Low Battery shows on the display when approximately 30 minutes of battery life remain. Slide off the back and replace the battery with a 9-volt alkaline. Accuracy of this meter is +/-2%. Accuracy drift is less than 0.1% per year, so yearly recertification is not necessary to meet the +/-5% IATA accuracy standard. Absolute zero, with all offsets set at zero, is +/- 1 milligauss. (Absolute zero accuracy is irrelevant when measuring air shipments for IATA magnetic compliance). Maximum measurable field is 2 gauss (2000 milligauss). To bypass the battery, plug in an AC adaptor with a standard 2.1mm power jack. It should be between 12 and 18 VDC, center positive, and at least 50 milliamps. Warranty is three years. Made by AlphaLab, Inc. 1280 South 300 West, Salt Lake City, UT 84101. USA Tel: 801-487-9492.