Griffin Technology

How can I measure how well ClearBoost is working? (Video)

These directions do not apply after the iPhone's 2.0 update. If you've updated your iPhone to 2.0, click here.

The most accurate way to determine the signal strength on iPhone is to enter "Field Test Mode." To do this, go to the keypad in the Phone application, enter *3001#12345#*, and tap Call. This will place you in "Field Test Mode." (This code works on all current iPhone firmware versions.)

From the presented menu, select "Cell Information".

Listed in the "Cell Information" screen are the cell towers the phone is in contact with. The strongest signal tower is listed at the top, the weaker ones below. The information reported about the towers you are in contact with will look something like:

RX: -90 FQ:188 ST:3 CI:31552 N:410 #310

The first set of numbers, the ones after RX, represent the amount of signal your iPhone is receiving from that specific cell tower, measured in dBm. This is the number set you should watch when comparing the reception benefit of the case. Since this number is a negative value, the closer you are to zero, the better. -111 would indicate that there is very weak reception, whereas a -60 would be very good reception. If a tower is showing a value at or below -106 dBm, you will most likely not be able to place a call using that tower.

The second set of numbers, displayed after FQ, show what frequency band the phone is currently using. If your iPhone is currently on the 850 MHz band, the FQ value will be in the 100-200 range. If the FQ value is in the 500-700 range, you are in a 1900 MHz area.

AT&T primarily uses the 850 MHz band in the US, and, as such, we designed ClearBoost to perform best at this frequency. However, if you are in a 1900 MHz service area, you should still see some benefit from using ClearBoost, though the amount of signal gain will be less than when compared to an 850 MHz area.

To take a measurement without the case, hold the iPhone in your hand as if you where talking during a call (the iPhone doesn't need to be against your head). Wait about 45 seconds for the signal levels to stabilize, and take a reading of all the available towers. As the towers are constantly shifting their power output, and the iPhone's reception can change at any moment, it may help to take a photo of the screen.

Then place the iPhone into ClearBoost, with both halves snapped shut, and repeat the test. Try to keep your hand in the same general area and orientation as in the previous test.

At this point, you should see an improvement in the signal (RX: value). Remember, an RX: -75 would be better reception than an RX: -80.

To put the RX: measurements in perspective, a change of signal strength of just 3 dBm, represents a doubling of the amount of RF energy reaching the iPhone's built-in antenna.

This video will show you how to access the Field Test Mode of your iPhone so you can see ClearBoost at work.

ClearBoost works by adding a booster antenna to your iPhone. But adding more antenna does not necessarily show up as more bars in your signal display. It's important to remember that the bar graph on your iPhone shows an average of many factors affecting signal strength. With ClearBoost, you can expect to see improvements that won't necessarily be reflected in the number of bars on your iPhone.

These improvements will, instead, translate into an increased ability to maintain connection with the cellular network, with more stations available to your phone, and less interference from signal reflections. This means fewer dropped calls, greater coverage areas, and faster Web browsing and file transfers.

More information and questions answered on the ClearBoost Support page.