# Hack 17. Display Signal Strength as a Number

Bars are for wimps! Be different and get in touch with your inner geek by displaying your wireless signal strength in decibels.

How many bars do you have? What does the number of bars actually mean? There are entire marketing campaigns by the wireless carriers about the bars that indicate the signal strength. But how does your device determine how many bars to throw up on your display? Surely there is some type of hard measurement that the device is doing to rank your wireless connection.

It turns out there is a hard number that represents the strength of your wireless signal and there is a BlackBerry keyboard shortcut to change the bars to display the actual number. From your Home screen, type Alt-N,M,L,L.

If you are using a 7100 series device or another Sure Type predictive typing enabled device, you'll need to type the following sequence: Alt-B,B,M,L,L.

After typing the sequence, you should see your signal strength meter change from bars (see Figure 1-47) to a number (see Figure 1-48). You can type the sequence again to go back to the bars for your signal strength.

##### Figure 1-48. The signal strength meter using numbers

You'll notice that this number goes higher when you coverage is poorer, and vice versa. This number is actually a reflection of what appears in the Status section of your Options program, as shown in Figure 1-49, without the dash indicating negative.

What exactly does that number mean anyway? Your signal strength is measured in units of dBm, which means decibels relative to 1 milliwatt. The GSM/GPRS radio inside your BlackBerry has a range of between 40 dBm at the highest and 120 dBm at the lowest (when you display the signal strength as a number, the BlackBerry doesn't show the minus sign). Your device will display a certain number of bars given the current dBm value. Table 1-7 shows the ranges of values that correspond to the number of bars that are displayed.

##### Table 1-7. Signal strength versus bars

dBm range

Number of bars displayed

-40 to-77

5

-78 to-86

4

-87 to-92

3

-93 to-101

2

-102 to-120

1

Your experience may vary, but you'll probably start to notice quality problems around-100 dBm.

Blackberry Hacks: Tips & Tools for Your Mobile Office
ISBN: 0596101155
EAN: 2147483647
Year: 2006
Pages: 164
Authors: Dave Mabe