Sunday, June 27, 2010

Cell Phone Signal Strength and Number of Bars

Here is a quick APPROXIMATE mapping between the number of bars on the cell phones and the signal strength in dBm. By the way, the reason signal strength shows with a negative sign is that it is measured as base-10 log of the signal strength. Therefore, 1/10 will be -1, 1/100 will be -2, 1/1000 will be -3 and so on. Therefore, the signal strength as measured in dBm increases or decreases progressively by a factor of 10. Of course, you will notice that we are dealing with very tiny numbers here. How big is 10-110!


 

Signal Strength in dBm

Approximate Number of Signal Strength Bars on Cell Phones

-114 to -108

1 bar

-107 to -98

2 bars

-97 to -94

3 bars

-93 to -90

4 bars

-89 and above

5 bars