In article , Stijn De Jong
wrote:

In the basement (cellspot is in the garage) I have -78dB currently. If I
go into the garage it's about -60dB-65dB, IIRC.

That's absolutely astoundingly high cellular signal strength (RSSI).
All the articles put the range at -50 to -110 or -120dBm.

-50 is the maximum possible, and below -120 there is no signal.

Are you getting that from your T-Mobile micro tower?
How do you know? (Because that's the entire reason for this thread.)

my iPhone displays the dB in the upper left corner. I's at -78 again.

I knew how you got the decibel RSSI (received signal strength indication),
but the question was how do you know which "tower" you're getting your
current signal from.

based on what you've written, no, you did not know that.

As far as anyone can tell, it's impossible to get the cell id tower from
the phone on an iOS device,

wrong.

so you have to use an Android device to figure
that out.

maybe you do, but the rest of the world doesn't, assuming they even
care what the tower id is.

everyone *other* than cellular engineers don't care, and the cellular
engineers have *far* more sophisticated equipment to find out than by
using an android or ios phone.