Field Test 4G Mobile Signal Strength

Want to know if Outdoor 4G Router works for you? Do a simple field test on your mobile phone by use your mobile phone to check the signal quality outside your house.

Step 1
Go outdoor your home or office with your mobile phone.

Step 2
Disable Wi-Fi connection on your mobile phone, then you to see what network you’re connecting to (2G, 3G, 4G, LTE, etc.).

Step 3
Take note of signal bars and the symbol in the status bar of your mobile phone and compare with below chart.

Symbol Mobile Networks Voice Call Internet Speed Email & Notification Video
(General Packet Radio Service)
Yes 50Kbits/s Yes No
(Enhanced Data GSM Evolution)
Yes 100Kbits/s Yes No
3G Third Generation
also known as UMTS / WCDMA / CDMA2000
Yes 2Mbits/s Yes Yes
(High-Speed Packet Access)
Yes 10-100Mbits/s Yes Yes
4G (LTE) Fourth generation or Long term evolution
also known as LTE or WiMax
Yes 100Mbits/s+ Yes Yes
No Symbol If signal bars get more than 1 bar
you can use voice call
N/A No No No

In your mobile phone, you can read signal bars followed by carrier name and network symbol which usually maxes 5~8 bars. To measure mobile phone’s signal reception in exact decibels instead of bars or dots, you can follow step 4 to enter Field Test Mode in mobile phones.

Step 4 – in iPhone iOS 12

i. Go into the Phone app and switch to the Keypad. Dial *3001#12345#* and press Call button. 
It will launch the Field Test Mode app on your mobile phone. 

ii. In the latest iOS 12, tap on Serving Cell Measurements.

iii. Look for Measured RSSI with numerical measurement of the iPhone 4G LTE cellular signal strength in dBm.

RSSI stands for Received Signal Strength Indicator
RSRP stands for Reference Signal Received Power
RSRQ stands for Reference Signal Received Quality

Step 4 – in Android Smartphone

Go to Settings > About Phone > Status > SIM Status and numerical signal strength will be available on either network or status which depends on the model of phone.

You can also use apps to show signal strength in decibels in Android phones.


1) The numerical value of 2G / 3G / 4G H+ networks is RSSI standard which is Received Signal Strength Indicator. LTE network is RSRP standard which is Reference Signal Receive Power. Hence, you need to turn off LTE on your mobile phone before entering Field Test Mode. 

2) Decibel signal strengths will be negative 2~3 digits.  Unit of measurement is dB. If your phone show a number such as 98, the actual signal strength is -98dB. The closer the number is to zero, the better the reception, so -90dB is a stronger signal than -100dB.

Easy table of signal bars and decibel signal strengths

Signal Bars iPhone Mobile Nokia Phone
5 > -85 dBm > -91 dBm
4 -85 ~ -90 dBm -91 ~ -101 dBm
3 -90 ~ -95 dBm -101 ~ -103 dBm
2 -95 ~ -100 dBm -103 ~ -107 dBm
1 -100 ~ -105 dBm -107 ~ -113 dBm
0 < -105 dBm < -113 dBm

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