Posted by Admin on August 02, 2015
In fact, the bars on your mobile phone mean almost nothing!
Anyone with a mobile phone knows that the bars-graphic on the home screen of our mobile phone is supposed to indicate signal strength; meaning how strong the signal strength is that our phone is receiving right now. And in a very broad sense, that is what the bars (or dots) on your mobile phone do - they indicate the relative strength of the available signal. Even the simplest looking phones by the children's phone manufacturer Firefly, displays the signal bars so the kids know how well the phone will work, wherever they may be.
But the key word here is "relative". What we mean by this is, if your phone indicates a signal strength between one and five bars (dots), then the three-bar display indicates a stronger signal than two bars, and a two-bar display indicates a better signal than one bar, and so on. But, unfortunately, that is all these bars (dots) graphics tell you. You cannot tell by viewing the bars-graphic just how strong the available signal is, or how much stronger your three bar signal is than a two bar signal, etc. Have you ever had the following experience? Your phone is showing three bars, but when you try to download or text you cannot do it because you apparently have no service - Despite the three bars on your phone!
The fact is that there are no standards for signal strength bars. All mobile phone manufacturers use their own algorithm to determine the strength level of the available signal: Then, using this algorithm they show you how many bars they choose.
So this means that there's no way to compare different phone model's signal bar strengths, because your mobile phone's two bars might actually represent a stronger signal than someone else's phone showing three bars. But how would you know, because you cannot compare the bar graphics.
Therefore, unfortunately, the bars do not mean much at all! This has been pointed out by many people over many years, but still today nothing has changed. The only way you can reliably determine how strong the signal available is for your phone is to take a dB reading. Because decibels are a standard unit of measure, when you take a dB reading you will know the real strength of the available signal.
Typically, dBm is expressed as a negative number, like -88 for example. Your cell phone signal is stronger the closer to 0 the reading is, meaning that -79 dBm is a stronger signal than -88 dBm. The strongest signal you will see is a reading of -50. You have a very weak signal if your reading is less than -100 dBm; and if it is much weaker than that you probably will not have any service at all.
Please see our other posts for instructions on taking a dB reading on both Android and iPhone devices. Finding out the signal strength reading of a cell phone in dBm reading mode is referred to, as putting the phone in the "field test mode". This is the only way to determine how strong your available cell signal really is; because the bars really don't mean much at all.