If you're getting H at the top of the phone it means you're still connected to the mast. If it said no signal then you wouldn't be able to make any calls. The fact that it says H suggests you'd still be able to make calls.
I spent the weekend in Norfolk a few weeks back, and had signal on Three where friends on other networks were getting drop outs. The only place TuneIn Radio dropped out was in Thetford forest, and even then only for a few seconds. I was really surprised.
Comments
Even with no bars?
Bars don't really mean much.
If you're getting H at the top of the phone it means you're still connected to the mast. If it said no signal then you wouldn't be able to make any calls. The fact that it says H suggests you'd still be able to make calls.