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What exactly is dBm and how does it affect your cell signaling system?

What exactly is dBm and how does it affect your cell signaling system?

Written by Sadia Jahangir
15th Nov 2022

Have you ever wondered how to get the most accurate reading of the signal strength of your cell phone? Those highly sought-after signal bars that we constantly bend, twist, and stretch to better access?

They are merely decorative. Although they can be useful to get a general idea of how strong your signal might be at any given location, the algorithm your phone or carrier uses to display decibels as cell phone bars is the only constant. The actual measurement is in decibel-milliwatts or dBm. While your friend may have three bars, it’s likely that your two bars are just as strong, if not stronger. Out of sync is not your actual signal strength but rather the carrier, phone model, and whether you are using 4G, LTE, or 3G. This does not imply that those bars are ineffective; rather, they are overgeneralized and lack a common starting point. The key is not as much acrobatics as it is a better comprehension of decibels in order to more accurately gauge signal strength, such as when determining the best location for a cell signal booster.


What's dBm?

The power and voltage strengths of electronic equipment, such as signal boosters or the wires and cables that connect to radio and audio frequencies, are represented by the relative scale known as the decibel (dB). Since the decibel is logarithmic and thusly a dimensionless unit, we apply the unit dBm, or decibel-milliwatts, as a flat-out perspective.

This indicates that power, or, in our case, signal strength, can be calculated by multiplying the log of the signal strength in milliwatts ten times. The ratio between two values is simply quantified by the dB, which is expressed as dBm. Therefore, you will only be able to measure any change in decibels (dB) once the dBm has been established.

In radio, microwave, and fiber optic networks, dBm is the preferred measurement because it can concisely convey both large and small values. The strength of a signal at any given location and the amount of power an antenna can amplify are both measured in dBm in the field of cellular signal boosters.

What is good signal strength in decibels?

A strong outside signal is typically measured between -50 and -70 dBm, while a weak signal is measured below -100 dBm (-110 indicates no signal at all). An indoor antenna with a radiating power of -20 dBm could effectively cover about 3,000 square feet, which would result in an exponential increase in the outside dBm signal. The logarithm states that the signal strength doubles with every third decibel. This means that a signal strength of -70 dBm is actually twice as strong as -73 dBm. Although the numbers may not indicate a significant change, the decibel levels have increased exponentially.

How do I use my phone to measure dBm?

Utilize the master precision of dBm signal strength measurements whenever the strength of your mobile phone signal is crucial. Apps like Network Cell Info make it simple to monitor and measure the dBm in real time wherever you go, whether you’re choosing the strength of your signal booster or where to install it for maximum efficiency. While most iPhones can access decibel information by turning on “test mode,” Android phones have a decibel-reading function built into their settings. The dB reading can be accessed by either sliding down from the top edge or by simply “calling” the number “3001#12345#” from the keypad. For step-by-step instructions on how to measure your dBm, see our comprehensive guide.

Not only will getting an accurate reading of your dBm signal strength help your cell phone booster antennas and amplifiers work at their best, but you’ll also sound like a true tech whiz the next time your friends are fumbling with their phones in search of those elusive bars.

What Can I Do If My dBm Is Almost Zero?

Fortunately, we have written a guide specifically for this purpose. While we would recommend a cell phone signal booster as the most certain method of combating poor signal, our guide also discusses free options.

Further Reading:

How Can We Help?

The most well-known manufacturer of cellular signal boosters is Bftsync. For home, office, or vehicle use, cell phone boosters can amplify 5G, 4G, LTE, and other networks for any phone with any carrier. They work best with an antenna pointed toward the nearest cell tower.

We truly detest dropped calls and poor coverage, so one satisfied customer at a time, we want to rid the world of spotty signals:

We truly detest dropped calls and poor coverage, so one satisfied customer at a time, we want to rid the world of spotty signals:

  • Contact our US-based customer support at for a complimentary consultation or call us at 1-281-616-5786 to ask us anything.
  • Free delivery.
  • Better signal or you’ll get your money back in 90 days.
  • We offer lifetime technical support and a two-year warranty on all products because we want everyone to be happy.

If you have any questions, we are happy to assist.


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