I think it might be the handset some handsets just tend have rubbish reception, maybe this is one of them? like the LG Chocolate i remember had rubbish reception, when i switched phones because i didn't like it in general, i got a Nokia E51 after and I used it in the same places i always do and i had reception and it was fine. so yeh if its your 4th phone try a different phone for a day or two and you might find the source the problem that way.