Summary

Low Cost Meters

You may wish to measure the intensity of the magnetic fields in your environment.  This is done with gauss meters.  In general, they cost more than $300.  However, we have come across several inexpensive meters.

We tested two inexpensive meters.  One, known both as "Dr Gauss" and as "Gauss Master," is available for $39.00 including shipping.  The other, CellSensor, costs about $54.00 including shipping.

Dr Gauss has, we believe, two good features and a serious failing.

Good Features:

1)  It costs only around $39.00, including tax and shipping.    

2)  It appears to be quite accurate.

3)  It has a clear, easy to read meter.  The numbers go from 0 to 1 at the low setting and 0 to 10 at the high setting.  They are fairly evenly spaced across the scale, thereby making it easy to read the settings.

Failings:

1)  It measures only from 0-10mG.  In a sense, that's OK, because the danger level for magnetic fields is 4 mG.  Nevertheless, for those who live near power lines, it would be nice to know if one is exposed to 10 mG or 40 mG.

2)  It does not have an off switch.  Rather, it turns itself off automatically after about five minutes.  In the meantime, it buzzes if it is in a magnetic field.

3) Similarly, the volume of its audible indicator cannot be altered nor can the audible indicator be turned off.

CellSensor also has good features and failings.

Good Features:

1)  It appears to be quite accurate.

2)  It measures up to 50 mG.

3)  It also measures cell phone magnetic fields (untested).

4)  It has an on-off switch. 

5)  Its audible indicator can be turned down or off.

Failings:

1)  The detector is separate from the meter.  This means it takes two hands to operate.

2)  Its meter is cramped and hard to read, especially at low intensity levels.

3)  The scale of the meter is 0 to 5 mG on the low setting and 0 to 50 mG on the high setting.  It is easier to comprehend a meter's results if the highest reading is 10 than if it is 5.  In addition, the high numbers are crowded together so that the "4" on the meter is very close to the "5".  This makes it even harder to read easily.  

On balance:

Dr. Gauss is clearly the meter of choice for those who do not need to measure intensities greater than 10 mG.  

CellSensor is best for those who need to measure intensities between 10 mG and 50 mG

How to Order:

Dr. Gauss can be ordered for $35.00 plus about $4.00 shipping at http://www.johnleemd.com/products.html.

CellSensor meter is also offered for about $54.00 at: http://www.action-electronics.com/cellsens.htm

Both the "Dr. Gauss/Gauss Master" and the "CellSensor" meters, together with additional cheaper and more expensive meters, are available at: http://www.lessemf.com/gauss.html.  At this time, the price of the meters is slight higher than at the the above two sites.

Accurate Measurements:

Both meters read the magnetic fields in only one direction, which leads to an underestimation of the true magnetic field.  Here is how to get a more accurate reading.  Move the meter around (or the probe in the case of the CellSensor) until the maximum reading is achieved.  Record  this maximum reading.  Then take the next reading by pointing the meter (or probe) either 90 degrees up or 90 degrees down from the original orientation.  Record the new reading.  Return to the maximum reading.  Then point the meter (or probe) either 90 degrees right or 90 degrees left and take a third reading.  Again, record the result. Then square each of the three readings, add them together, and take the square root of the result.  This is the final result.  Therefore, if the first reading was 10, the second reading was 6, and the third reading was 3, the final result would be the square root of 145 (100+36+9) or a bit over 12.  Note the final result is always greater than each of the individual readings.