Check Actual Signal Strength on iPhone in iOS 11 Using Field Test Mode

Want to find out the actual cellular signal strength on iPhone running iOS 11? Follow this straightforward guide to use Field Test Mode on your iPhone to figure out how strong the connection is. And, do share your thoughts about the change that seems to have disappointed many users.

When the cellular connection starts playing hide and seek on my iPhone, I take the help of “Field Test Mode” to gauge the real signal strength on the device, as signal bars aren’t much helpful. Apple has slightly tweaked its functionality in the latest version of iOS. Unlike before, it no longer displays cell signal as the number in iPhone’s status bar. So, how do you use Filed Test Mode in iOS 11 to find out the accurate signal strength on iPhone?

Despite the noticeable change, you can still see the cellular connection in decibel milliwatts (dBm) in iOS 11 or later. While the process is the same as before, you can’t make the number appear in the status bar. I wish there were a way to get it done! Anyway, let’s find out how it works:

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Things you need to know:

  • Ensure that your iOS device has an active cellular connection so that it can access and use Field Test Mode to measure the signal strength.
  • One thing worth noting is that you will be able to check the 4G-reception strength to the nearest cell tower only on the iPhone with an Intel wireless modem. I’m sorry, you can’t get it on the device with Qualcomm modem.
  • Though you will be able to get the similar data readings on both versions, only the Intel wireless chips equipped device will display dBm.
  • The devices on which you can see the cellular connection in decibel-milliwatts are iPhone X: A1901, iPhone 8: A1905, iPhone 8 Plus: A1897, iPhone 7: A1778 and iPhone 7 Plus: A1784. Go to this post to check if the model number matches.

How to Check Actual Signal Strength on iPhone in iOS 11 Using Field Test Mode

Step #1. Launch Phone app on your iPhone.

Step #2. Now, you need to enter the number: *3001#12345#*

Step #3. Next, you need to hit the Call button to dial the number.

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Dial 3001 12345 on iPhone

It will open the hidden “Field Test Mode” on your device.

Step #4. Next up, tap on LTE and select “Serving Cell Meas.”

Tap on LTE then Tap on Serving Call Meas After Calling

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Step #5. Up next, you need to find the “rsrp0” and check out the corresponding number. It’s the numerical measurement of your device cellular signal strength in dBm.

Check Actual Signal Strength on iPhone

It would be shown as negative number and range from -40 to -130. While anything around -80 is considered to be very good, the -110 or lower is said be too bad. On my device, it’s -90 which is believed to be pretty fine.

You may also want to check out the rsrp1 (“reference signal received power”) the closest backup tower and its corresponding number. It would come into the picture if the main tower is out of order or not working.

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Check Closest Backup Tower on iPhone

That’s it!

Over to you:

Hopefully, Apple reverts the functionality of “FTM” on iOS 11 sooner than later. What’s your take on it? Toss up your thoughts in the comments below.

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You might want to read these posts as well:

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Jignesh Padhiyar
Jignesh Padhiyar is the founder of who has a keen eye for news, rumors and all the unusual stuff that happens around iPhone and iPad.


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