Alert
Alarm
Instructions
The MicroAlert Alarm detects radio and microwaves, causing the device to produce and electronic "chirping" sound / beep when the field strength detected is higher than a level that you have adjusted / set the instrument to.
Locate the "power" switch on the top surface of the device, just above the words "OFF ON". Slide this recessed switch to the "ON" position. You should hear a single beep / chirp when this has been done, which indicates the battery is good. The unit is now working. The small black knob marked SENSITIVITY, which is on the right face of the box, is normally set at the factory to its center position. Notice the line that is indented into the small black knob. The "center position" means that this indented line points toward the arrow next to "NORMAL", which is on the label of the MicroAlert. If you rotate this knob clockwise, it will increase the sensitivity.
Counterclockwise rotation of the knob will decrease the sensitivity. The "center position" represents a certain sensitivity, though the sensitivity depends to some extent on how the MicroAlert detection face is positioned. If held up in the air with your fingers on the lower half of the case, with your fingers beside or below the word "MicroAlert 2", this "NORMAL" sensitivity is about 5 microwatts / cm2. This is the strength (or technically, the power density) of the radio / microwaves that will cause the unit to just begin to beep. The beeps will repeat at about 4 per second if the average power density is just at this threshold of 5 microwatts / cm2. If you move to an area where the power density is higher, the beeping will become more frequent (as frequent as 20 beeps per second). Above about 10 microwatts per cm2, the beeping becomes a solid "always-on" tone.
ADJUSTING THE SENSITIVITY
If the SENSITIVITY knob is turned all the way clockwise, the unit should begin beeping (a few beeps per second) by itself, even if there is no radio/microwave present. You can shield the MicroAlert from these waves simply by cupping it in your hands.
Then the unit, if correctly calibrated, should be beeping. However, if you turn the SENSITIVITY knob halfway toward horizontal (see ".1" in the diagram posted below), the beeping should stop provided that the MicroAlert is cupped in your hands. If the unit beeps in both knob positions or if it beeps in neither position, then it needs calibration. This is a simple operation which will be described below.
The diagram below shows the approximate minimum strength of radio / microwave, measured in microwatts / cm2 (units of power density) that is required to make the MicroAlert start beeping. These numbers depend on where the SENSITIVITY knob is set, and are accurate within about a factor of two if the radio / microwave signal is in the frequency range 6 MHz – 3 GHz.
Frequencies below 6 MHz are discussed in the ADDITIONAL MICROALERT ALARM OPERATING INFORMATION section near the bottom of this page.
The diagram data assumes that you're holding the MicroAlert in front of you and that your fingers are holding the lower half (not blocking the upper half with your hand, etc.). The MicroAlert is reading the vertically-polarized electric field component of the radio / microwaves, which in most cases represents most or all of the power present. In the diagram, the higher number, in parentheses, is the power density required to make the unit produce a solid tone, not just a beeping / chirping sound.
If you set the MicroAlert standing up on a metal surface, the sensitivity is about the same as shown above. However, if you're carrying the MicroAlert in a pocket or have it set down flat (not standing up) on a surface, sensitivity is about 1/4 of that shown in the diagram. That is, at the most sensitive knob setting, which is marked ".1 (3.5)" on the diagram, the minimum power density required to make the unit start to beep is .1 x 4 = .4 microwatts per cm2, and the power density required to make the unit produce a solid tone is 3.5 x 4 = 14 microwatts / cm2.
Therefore, multiply all the numbers you see on the diagram by 4 if the MicroAlert is neither held upright in your hand nor standing up on a metal surface.
CALIBRATION PROCEDURE
If the MicroAlert does not perform / operate as described above, when set at the two most clockwise positions shown on the diagram, calibration is necessary.
The MicroAlert should beep even when it is shielded (by being cupped in your hands), if the knob is set to the "Maximum clockwise travel" position, however it should not beep when set to the ".1 (3.5)" position if it's cupped in your hands.
To calibrate the device, unscrew the single screw on the backside of the MicroAlert (the small screwdriver is included with your MicroAlert especially for this procedure). Rotate the black knob to its most sensitive position, at maximum clockwise travel. Inside the MicroAlert, you'll notice a copper rectangle with a hole in it. This is the antenna. Stick the screwdriver through the hole so you can rotate the small round control under the hole. Rotate this round control so that the MicroAlert beeps a few times a second. (This beeping should be heard after you take out the screwdriver and cup the MicroAlert in your hands.) Then turn the black knob to the ".1 (3.5)" position shown in the diagram. Now the unit should not beep when cupped. Of course, it's easiest to do this test in an area that seems to already have fairly low radio / microwave signal. That is, an area where there's not much difference between the microwave field the MicroAlert picks up whether you hold it upright or cup it in your hands.
BATTERY
Battery life is typically 3 years if it isn't beeping more than about 5 minutes a day. If you don't hear a beep when you turn it on, replace the battery. Also as the battery voltage drops, the beep volume will be softer / quieter. The weak battery does not affect the sensitivity level, but if the beep sound becomes too quiet to be useful to you, then you should consider replacing the battery.
It uses an inexpensive lithium "2032" (CR 2032) type 3 volt battery, available from any store / site which has batteries for sale. To replace it, unscrew the center screw and follow the directions printed inside the MicroAlert on the green board. You need to push down on the white plastic round tab (looks like a cul-de-sac) with a few pounds of force until you hear a click, then the battery will be at a slight angle. Pry the battery out with the screwdriver. If you accidentally put the new battery in backward, it will not harm anything, but the unit will not work until you put the battery in with the "+" side facing up. After sliding the battery into position, push down on the battery on the side which is sticking up the most, so that it will sit flat in the holder. Replace the cover of the MicroAlert Alarm.
ADDITIONAL MICROALERT ALARM OPERATING INFORMATION
Avoid strong static electric sparks around the MicroAlert. These might shift the sensitivity level and could require you to calibrate it. For 6 MHz radio waves, the unit is about half as sensitive as it is in most of its range. This means you should multiply the numbers in the diagram by two if you know the wave is 6 MHz. It is less sensitive at lower frequencies than 6 MHz. At 5 MHz, multiply by 3. At 2 MHz, multiply by 7. At 1 MHz, multiply by 20, and at 500 KHz, multiply by 50 (that is, it is 1/50 as sensitive). General maximum public exposure to microwaves is 10 microwatts/cm2 in several European countries. In the US, the maximum allowable is much higher, at approximately 600 microwatts/cm2, for typical cell tower frequencies (the maximum allowable exposure depends slightly on the actual frequency of the microwave field in question). The MicroAlert does not detect 600 microwatts / cm2, though it can be used to check European Standards, which are within it's range of detection. In most areas in US cities, the level is below 10 microwatts / cm2.
One-Year Limited Warranty
Manufactured in the U.S.A. by AlphaLab, Inc.
(See order page for address and contact information)
Email: EMF Meters
