If you're looking to purchase a cell signal booster for a building or stationary RV, there are two critical measurements of the outdoor signal you need to know before purchasing:
You can find this information by entering Field Test Mode on iPhones, or using specialized apps on Android devices.
We're all familiar with our phone's signal bars. But what do they actually mean?
Well, it varies from phone to phone. Each manufacturer makes a decision on how to combine "signal strength" and "signal quality" measurements and translate them into bars.
But getting exact RSRP and SINR values gives you a much more granular view of your signal, and will help determine which signal booster is the right choice.
iPhones with Qualcomm chipsets do not support signal strength and quality measurements in field test mode, but iPhones with an Intel chipset do. You can find out which chipset your phone has based on the device and model number.
The following devices and model numbers have Intel chipsets and will show signal strength (RSRP) and signal quality (SINR) values:
The following devices have Qualcomm chipsets and will not show signal strength and quality information:
To find your model number:
If you're using an Android device, we actually recommend using the Network Cell Info Lite application instead of field test mode. The app provides easy access to all the signal information provided in Android's field test mode.
One important note: if the app is showing your SINR as 30 dB, that means it's not measuring SINR correctly. You can instead use the "RSRQ" measurement for signal quality. If your RSRQ is greater than -10 dB (e.g. -6 dB) then your signal quality is good. If SINR is less than -12 dB your signal quality is low.
If you still want to access field test mode on Android phone, you can enter "Settings" then select "About Phone." Your signal strength in decibels (dBm) will be displayed under “Network” or “Status.”
An alternate navigation sequence for some Android phones is Settings –> More Options or More Settings –> About Phone –> Mobile Networks –> Signal Strength.
Signal strength (RSRP) is measured in decibels milliwatts (dBm).
A higher values means a stronger signal. But all the values are negative, so don't get caught out! -60 dBm is stronger signal than -80 dBm, -80 dBm is stronger than -90 dBm, etc.
If your RSRP is lower than -80 dBm (e.g. -90 or -100 dBm), you should use a 100 decibel single-carrier booster like the Cel-Fi GO X, or for larger buildings, the Cel-Fi Quatra 2000. Please note: If your signal strength is less than -115 dBm, even the GO X and Quatra likely won't work well without a very high gain antenna like our Grid Parabolic.
Signal quality (SINR) is measured in decibels (dB). Any SINR measurement over 10 dB is excellent, over 5 dB is considered good, while over 0 dB is acceptable. A negative SINR means that you have low signal quality.
A booster will help increase the signal strength, but it won't help improve the signal quality. The only way to improve signal quality is to buy a high gain antenna like our Grid Parabolic, which requires careful aiming.
As a general rule, -80dB or higher (ie, -70, -60, -50) is considered strong signal. -110dB or lower (ie, -120, -130) is very weak.