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How To Use Field Test Mode To Measure Cell Signal Strength

Updated: Apr 6, 2023

How To Use Field Test Mode To Measure Cell Signal Strength

Did you know that your phone contains a special feature that allows you to check and analyze the strength of the cellular signal around you in nearly any environment? Field test mode is a helpful, beneficial, and impressive feature on almost every cell phone, from older Nokia models to modern smartphones from Apple or Samsung. If you're wondering how to use field test mode to measure cell signal strength, SureCall Boosters is here to explain how to access this feature and analyze the information you find.

What Is Field Test Mode?

How do you use field test mode? Before we get into the details of activating your field test mode, it’s a good idea to learn what this mode is. This application, sometimes called "field test display," comes standard on most modern cell phones and allows users to better understand their current signal strength.

Traditionally, most phone manufacturers don't advertise the field test mode because much of the information is more beneficial to technicians, engineers, and other professionals who may require this data for more technical purposes. However, just because this information may not offer much to the average user doesn't mean field test mode lacks practical data when checking signal strength. It's essential to remember that depending on the phone's carrier, the same type of phone in the same spot may have stronger or weaker signal strength.

While many people look at the strength of their signal in terms of bars or by the specific network type (LTE, 4G, 5G, etc.), this is not always the most accurate way to gauge your signal strength. We recommend initiating field test mode for more precise and detailed results.

Activating Field Test Mode on iPhone

Field test mode is available on iOS 16. In fact, Apple enabled field test mode in all iPhones running iOS 4.1 or newer, meaning if you have an iPhone, you most likely have access to this feature. The following steps work with any iPhone running iOS 9.3 and above, which should work with most currently running devices.

To get the most accurate reading based on your current position and external signal, you want to first go to Settings and disable the wi-fi. After disabling the wi-fi, go into Cellular Settings and turn off your LTE. Turning off LTE gives you a better signal reading with more accurate information.

Once your wi-fi and LTE are off, pull up your phone’s keypad as if you intend to call and dial the following:

*3001#12345#* followed by the Call button.

This should take you to the field test display and give you several options such as your SIM info, serving cell measurements, and your connected mode. Once in this mode, follow the steps below to find the most relevant information to your signal strength.


Click the menu icon at the top right-hand side of the screen.


Click "Serving Cell Info".


Note the readings in "Band Info" and "RSRP".

Band Info - indicates which frequency band your phone is connected to.

RSRP - indicates your phones signal strength in dBm. The lower the number, the worse the signal. Ie: -115dBm is worse than -100dBm

Activating Field Test Mode on Android

Using field test mode on your Android is similar to the process for iPhones. The process for those with Samsung phones or other devices running an Android operating system is also straightforward, even if it’s not a regularly advertised feature. The specifics may vary depending on what model of phone you have but go to your phone's settings and select About Phone. The strength of your phone should be available under Status or Network. Some phones include an additional option called Network Type.

Like iPhones, once you get to your field test display, it may take between 30 and 60 seconds to give you a precise reading. The information will include the signal strength in decibels, your phone's carrier, and your current network type based on your location (2G, 3G, LTE, etc.).

Apart from using the preinstalled field test mode with your Android device, several apps can provide you with similar information, such as Network Cell Info Lite or Signal Strength. Utilizing the data from your phone and checking it against the information you get from these signal testing apps may help give you a more precise reading by comparing the different totals and seeing how closely they match up.

What Do the Decibel Readings Mean?

When you check your signal strength, it’s normal to see negative numbers ranging from -50 to -120. The general idea is that the closer your number is to zero, the stronger your signal is. This means a signal at -60 decibels is stronger than one at -70. Typically speaking, anything lower than -100 is when you may notice weak signals, dropped calls, and other frequent hassles of an unreliable signal.

These numbers may vary slightly depending on your service provider or phone, but a good rule is to aim for a signal level in the double digits.

Why Use Field Test Mode?

As mentioned earlier in this article, field test mode serves a valuable purpose. However, most phone companies and carriers don't promote it very heavily because much of the data found in the field test display is more for those working in the industry. The vital information the field test display provides carrier companies and cell service providers allows them to find weak spots in their signal and install towers to boost them. Working to boost signals provides higher-quality service for customers, making it more likely they’ll sign on with a particular service provider.

However, ordinary people checking their phones may also use this information to determine if a cell phone booster antenna is the right choice for them. If you use field test mode and discover the signal around your house or workplace is weaker than you anticipated, investing in a stronger signal to prevent dropped calls and increase the quality and performance of your phone may be a good idea.

If you have any further questions or comments regarding how to use field test mode to measure cell signal strength or find your signal to be on the weaker side and want more information on how you can improve it, please consider reaching out to the friendly specialists from SureCall Boosters. You can reach out to us by phone during normal business hours at 1-888-389-5799 or email us anytime at To learn more about utilizing field test mode or how cell signal boosters can improve your business, explore our blog.

How To Use Field Test Mode To Measure Cell Signal Strength

1 Comment

Diksha Gupta
Diksha Gupta
Sep 15, 2022

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