Today we’ll show you how to detect 4G network in your Android phone.
In many cases 4G network may not show up in the network search & even if it does, you have no idea of knowing how strong the signal is.
You don’t need any 4G SIM for this to work. Here is the procedure
1. Download & install NetMonster & LTE Discovery apps from Play Store. For LTE Discovery, you need to be rooted & phone should have a Qualcomm processor.
2. Open NetMonster & ensure that it’s showing your current 2/3G network (check MNC-MCC code).
Click on the 3 dots on top-right & then Radio info.
Note: Radio info is the same screen which is opened by *#*#4636#*#*
3. Scroll down to ‘Set preferred network type:’ which is just above TURN OFF RADIO button.
4. Click on the drop down menu & you’ll see lots of options like GSM auto (PRL), WCDMA only, LTE only and many more.
5. Select LTE only (if netmonster crashes after selecting LTE only in radio info, then first select WCDMA only, wait for full signal to appear on top, then go for LTE only & return to netmonster.)
6. Your signal should go zero. After a few secs, you should see the details of whichever 4G network has maximum signal strength in your area. It could be anything, like Airtel, Jio or Idea (check MNC-MCC code for Jio for your state). Personally, I never get anything else other than Jio ever since they turned on their towers, meaning Jio’s signals are strong in all the places I tested. You can also see the RSSI/RSRP which indicates how strong the network signal is. Anything greater than -100 dBm (like -95) is very good. You can also see the adjacent 4G cells with respective signal strengths.
7. You can also open LTE Discovery app where you can see the LTE cells with band (3, 5, 40), frequency, signal strength details. However you need to be rooted with a Qualcomm processor.
8. Go back to radio info & select whatever network it was in previously (normally GSM auto (PRL)) to restore your signal.
Have a look at screenshot below: 
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Reply below with 4G network name you see & its dBm strength if it works for you.