Do you suffer from poor range? With the Field Test Mode you can see the signal strength of your mobile network. Read here how to activate the Field Test Mode and see if you have good range from your provider.
Everything about Field Test Mode
Sometimes you are dealing with poor range on your iPhone. The dashes at the top of the screen indicate how strong the signal is, but that is not very accurate. With the so-called Field Test Mode on the iPhone, you can see exactly how good the range of your provider is. In older iOS versions, you can even replace the number of dashes with a number. This way you can easily compare the coverage of different providers with friends. The Field Test Mode is intended for technicians and is not something you need every day as a regular user. Hence it is somewhat hidden.
- New! Field Test from iOS 14
- Field Test in iOS 11 to 13
- Field Test for iOS 11
- How does Field Test work?
- What is RSRP?
- Other terms
- Other codes
Field Test Mode from iOS 14
The Field Test Mode has got a new look in iOS 14. The information is clearly arranged and you don’t have to dig as deeply. For example, there is now a home screen (Home) with all important info. Scroll to the tab All Metrics, you will see the measurements of LTE, UMTS and GSM broken down.
You activate the Field Test Mode * 3001 # 12345 # * key in the Phone app, then press the green button to connect. You will then see the following:
Previously, the Field Test mode allowed the strength of the mobile signal to be displayed continuously in a number instead of dashes. That is no longer possible nowadays. You will now have to look it up yourself.
- In the Field Test app, go to LTE.
- then choose Serving Cell Meas.
- The measurements at rsrp0 and rspr1 show the signal strength in decibels-milliwatts.
The numbers are always negative and are between -50 and -130. The closer to 0 the better. A signal strength of -50 is excellent, while the values on the image are close to -100 and thus indicate a weaker signal.
Field Test Mode from iOS 11 to iOS 13
You activate the Field Test Mode as follows:
- Open the Phone app on the iPhone.
- Enter * 3001 # 12345 # * and press the call (don’t forget the asterisks at the beginning and the end).
- You switch to Field Test Mode.
- Tap on LTE> Serving Cell Meas or LTE> LTE Neighbor Cell Meas (this is short for ‘measurement’).
- Look at the value rsrp, or Reference Signal Received Power.
The number is given in dBm and is somewhere between -40 and -130. -40 is the best possible signal and -130 is the worst. In most cases, the value is around -80 and -100.
Between -110 and -130 you will experience problems with your range, so calls will not get through and your data connection will falter.
The values rsrp0 and rsrp1 refer to the two antennas present in the iPhone. One is at the top of the device and the other at the bottom. Each antenna measures its own signal strength depending on distance, interference and other factors. The two values should be close to each other.
Here’s how the RSRP value in iOS 11 translates to dashes:
You can still browse through the rest of the Field Test Mode, but many screens do not contain any useful information. You could compare the signals with someone else. It will differ per iPhone type, per copy and per provider.
Exit Field Test Mode
To exit Field Test Mode, simply press the Home button or swipe up again on a device without a Home button. Using the Field Test Mode has no further consequences, so you can feel free to see what is available. If you want to view some statistics again after closing, just follow the steps as mentioned above.
How do I get the signal strength in the status bar?
Unfortunately, since iOS 11 it is no longer possible to show the signal strength in the status bar. Also, you won’t see the value if you have iOS 10.3 installed on an iPhone 7 or later. This is still possible on older iOS versions before iOS 10.3. If you want to know more about this, we will explain how it works below.
How does Field Test Mode work?
With the Field Test Mode you can request detailed information about your mobile signal and the mobile connection. The Field Test Mode is actually intended for network engineers, but as a regular user it can also be nice to see how good the mobile range of your provider is in a certain location.
The option has been around since iOS 4.1 but has been changed in iOS 10.3 and 11. As a result, it is no longer possible to continuously view the signal strength in the bar at the top of the screen, as shown in the image below. But you can still manually request the signal strength.
Mobile phones measure the received signal strength in dBm (decibels in relation to 1mW). This is a logarithmic scale where 1mW equals 0 dBm. This figure is translated into a number of dashes in the bar at the top of the phone screen. Depending on the strength of the signal, you will see 1, 2, 3 or 4 dashes. Before iOS 11 appeared, the signal strength was shown in dots instead of dashes. You were shown four dots if the signal strength was between -85 and -94 dBm. There was also a fifth bullet for signal strengths above -85 dBm. Note that these are negative numbers, so -85 is greater than -94.
The Field Test Mode allows you to see the signal strength much more accurately than if you only look at dashes or dots. The appearance of the Field Test Mode screens varies by device.
What is RSRP?
RSRP (Reference Signal Received Power) is the most important value. This determines the number of bars you see. The values rsrp0 and rsrp1 refer to the two antennas in the iPhone.
SINR stands for Signal-to-Interference-plus-Noise Ratio. If there is a lot of interference from other radio signals in the area, then SINR is actually used to determine the number of dashes.
RSRQ (Reference Signal Received Quality) also takes noise and interference into account.
RSSI (Received Signal Strength Indicator) is an alternative signal strength indicator, but unlike RSRP and RSSI, does not take interference into account and depends on bandwidth and amount of data traffic.
Field Test Mode before iOS 11
On older iOS versions, enable Field Test Mode in the same way as described above:
- Open the Phone app on the iPhone.
- Call * 3001 # 12345 # * (don’t forget the asterisks at the beginning and the end).
- You switch to Field Test Mode.
- At the top left you see the strength of the signal, but this is temporary. As soon as you leave Field Test Mode you will see the normal balls again.
Whether the signal strength is visible in numbers depends on whether or not your device has an Intel chip and it also depends on the provider.
Signal strength in the status bar on your iPhone
If you prefer to permanently see the signal strength of the mobile network on your iPhone, you will have to take an extra step. As mentioned, it only works on devices before the iPhone 7 and before iOS 10.3:
- Open the Phone app on iPhone and call * 3001 # 12345 # * as explained above. You are now switching to Field Test Mode.
- Press the power button until you can turn off the iPhone.
- Then press the home button for 6 seconds.
- You will now return to the home screen. At the top left you see the number with which you can read the signal strength (the range). By tapping the number you switch from dots to a number value.
Signal strength: what is good?
How do numbers translate to dots in older iOS versions? Do you see a value -90, is that good or bad? In the list below you can see how the values correspond to the number of spheres. Signal strength is measured in dBm. The higher the number, the better the signal. At a signal strength below -120 dBm, there is hardly any range left. With a good range, the figure will be between -51 and -100. A value of -90 is usually good enough and corresponds to 3 dots.
The translation of dBm values into spheres works as follows:
1 ball: approx. -121 to -107 dBm
2 balls: approx. -107 to -98 dBm
3 balls: approx. -98 to -87 dBm
4 balls: approx. -87 to -76 dBm
5 balls: approx. -75 and more
Please note that it is up to the provider and the phone manufacturer how these values are converted into spheres, so in the border areas you may see one dash more or less. With the Field Test Mode you can now easily check to what extent your provider has poor coverage in a certain area.
If you are still using an old iOS version, you can read more about Cell Information in a separate article.
If you no longer want to see the signal strength as a number, you go through the same actions to make the signal strength temporarily visible, so by entering * 3001 # 12345 # *. If you leave the Field Test Mode, the value in numbers will also disappear.