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dB Gain: The Most Important Thing to Your Cell Phone
8th Mar 2017 /
by James N / Comments

dB Gain: The Most Important Thing to Your Cell Phone

What is dB gain?

Well, without it, forget about calls, emails, texts, internet, social media, apps, and almost everything else about your smartphone.

That's because dB gain reading is the best way to read signal strength on your cell phone.

But what about cell phone bars?

Not even close.

dB reading is the best method and here's why:

The Most Accurate Way to Read Cellular Signal Strength

Cell phone signals are basically radio frequency waves. It's the AM/FM kind that broadcasts over the air.

3G & 4G operate within a certain frequency (700 to 2100 Mhz) and an optimal signal level.

That signal level is measured in dBm: from -50 dBm to -120 dBm.

-50 dBm is fantastic signal, full bars. -120 dBm is very poor signal, zero bars.

This is true for all cell phones & all carriers in North America.

But what about cell phone bars?

Well, raise your hand if you've ever encountered this before: You look at your cell phone and there are 2-3 bars, yet everything is loading, choking on connection, and just sputtering despite having "good" signal.

That's because cell phone bars are subjective across all carriers. So there's no industry standard for the number of bars to cellular signal strength. It's up to the carriers to consider what they think is one, two, three, four, and full bars on their own networks.

So what might be 1 bar on Verizon might be 2 bars on T-Mobile or 3 bars on AT&T despite having the EXACT same signal & speed.

Confusing, yes?

But not with dBm gain. It's scientific, it's carrier-agnostic, it's just pure math.

So, let's find out how you can locate dBm readings on your phone.

Finding Your Decibel (dBm) Gain Reading on Your Phone:

For iPhone Users

Starting with iOS 11 and 12, Apple has hidden dBm readings in iPhone field test mode. However, depending on your iPhone chipset (Intel or Qualcomm) and your carrier (Verizon, AT&T, T-Mobile, or Sprint), there’s a slim chance to find your dBm readings through this workaround.

Here’s how:

AT&T or T-Mobile iPhone with Intel chipset (iOS 11 & 12)

  • Dial *3001#12345#*
  • Tap LTE.
  • Tap Serving Cell Meas.
  • Your dBm is read as rsrp0.

Verizon or Sprint iPhone with Qualcomm chipset (iOS 11 & 12)

  • Dial *3001#12345#*
  • Tap 1xEV-DO.
  • Your dBm is read as RX AGC0.

For any iPhone pre-iOS 11

  • Dial *3001#12345#*
  • Swipe down notifications bar.
  • Your dBm is in the upper left-hand corner of the screen.

If you’re unable to find any of these options during your field test mode process, you most likely have an incompatible carrier and chipset. The next best method is performing a speed test around areas inside and outside your home. But once we crack the code on dBm readings on your iPhone, we’ll update as soon as possible.

For Android Users

Field test mode on Android varies by phone model and Android OS version. However, it is generally found under the Settings menu.

Typical sequence:

  • Tap Settings
  • Tap About Phone
  • Tap Status or Network
  • Tap SIM Status
  • Your dBm is under Signal strength

Once you have your dBm reading through field test mode or app, walk around inside and outside the perimeter of your home. Make note which areas get the best dBm reading. This shows you the general direction of your cell tower and which rooms inside your home have the best reception.

Next Steps: 1-2 Buckle Your Shoe (or Sandals)

Once you have a dBm reading on your phone, walk around outside of your home around the perimeter. Walk slowly since it takes time for cell phone signal to refresh. After about two or three trips, you should get a very good idea which area of your home gets the best signal.

And on top of that, now you know the general direction of your nearest cell phone tower.

So let's take a look at a general dBm reading and its relation to signal strength.

dBm Reading:

Great signal: -50 to -79 dBm.

Good signal: -80 to -89 dBm.

Average signal: -90 to -99 dBm.

Below average signal: -100 to -109 dBm.

Poor signal: -110 to -120 dBm.

So what's your dBm? In general, anything at -50 dBm to -95 dBm is considered good working signal. From there on, -96 to -120 dBm is where you get spotty connections, dropped calls, and poor coverage.

So if you fall within that poor signal range, what are your options? Well, we've written some tips about getting better signal, but if you want the best method, it's about boosting your cellular signal.

Raising The Bar

Cell phone signal boosters are FCC-certified devices that take weak cellular signal and boost it multiple times up to 32X. With most home & car units rated at +50 to +70 dB, they potentially not only bring back lost signal but also amplify it to new heights.

That's why it's called dB gain whereas dB loss means you're losing signal (usually because of cell tower distance, external interference, and building material.)

It's also important to note that dB gain (and loss) are measured exponentially.

A +3 dBm gain actually doubles signal strength! Conversely, - 3 dB mean 1/2 the signal strength. So let's look at a dB chart:

dB Gain Power Amplified
+ 3 dB 2x
+ 6 dB 4x
+10 dB 10x
+15 dB 32x
+20 dB 100x

Even a slight bump in dB can lead to much more amplified power! So don't rely on bars, use dB reading when you want to know your real signal strength. Happy dB hunting.

How May We Help You?

Wilson Amplifiers is the leading provider of cell phone signal boosters. Cell phone boosters amplify 3G & 4G LTE for any phone with any carrier for home, office, or vehicle.

We seriously hate dropped calls and poor coverage, so it's our goal in life to stomp on spotty signal like the little roaches they are:

  • Free consultation (ask us anything) with our US-based customer support ( or call us at 1-800-568-2723.
  • Free shipping.
  • Better signal or industry-leading 90 money-back guaranteed. No questions asked.
  • We want everyone to be satisfied, so we provide lifetime technical support and a 2-year warranty for all products.

Ask us anything and we'll be glad to help.

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