“
The tl;dr version of this is: the signal strength bars are almost meaningless and should not be relied on.
Incidentally, this also explains what’s going on when you have a strong signal, attempt to make a call, and can’t connect. The bars only indicate how well your phone can listen to the cell tower. They don’t tell you anything about how well the tower can receive your phone, but that’s a pretty important part of making a call.
