Posted by Admin on May 10, 2017
Find out what exactly dB and dBm acronyms mean? What is the difference between dB versus dBm, and how or when are those terms used in the cell phone signal booster industry?
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In a nutshell, you can think of dBm as amount of power an amplifier or antenna is capable of producing. Or how much signal strength exists at a location or site. Thus, when our installers measure existing signal strength outside a building to determine how strong of an amplifier will be required, they state signal strength in dBms in the system design as in -60 dBm (meaning strong signal strength) or -110 dBm (meaning very weak signal strength). It is an absolute measure of signal strength. It is an abbreviation for decibel milliwatts. It is calculated as 10 times the log of the signal strength in milliwatts.
On other hand, dB or decibel is a relative number of the amount of increase or decrease in signal. Thus, our cell phone signal boosters state how much maximum dB Gain they can provide, or how much they can "increase" cellular signal. The description of a particular cell phone booster may state that the cable attenuates (or reduces) signal by maybe 2dB for every 10 ft. Therefore, dB in that instance is referred to, as amount of signal decreased.
dBm is an important figure of merit when measuring outside signal strength. We typically think of an outside signal as being strong when it is -70 dBm or better. It is considered poor when it is -100 dBm or worse. dBm is also useful for estimating indoor coverage area you might expect from an amplifier system. For example, an indoor antenna that is radiating -20 dBm can effectively cover about 300 square feet.
This is a relative figure and is simply an abbreviation for decibel. We use dB to describe how much increase or decrease in signal strength we have in our system. For example, if we measure an outside roof-top signal of -90 dBm, and when we mention that a particular amplifier system provides a total gain of 70 dB. Then our inside radiated signal will technically be -20 dBm which is outstanding (anything better than -60 dBm is great mobile reception).
The normal ways we're used to thinking about magnitude no longer apply. For example, a -30 dBm signal is twice as powerful as a -33 dBm signal. And a -84 dBm signal is four times as powerful as a -90 dBm signal. The signal strength doubles every 3 dB.
This subject is obviously much more complex and there's much more to know. But it will give you a basic understanding of what these terms refer to. This will help you when it comes to installing wireless signal amplifiers. Please contact us if you need professional installation service for installing your commercial grade signal boosting system. Thank you!