hi @all that have c62 with netwrok problems.
I have had many pieces of that phone and every time the problem is different (most of the cases rehoting of RF or ant. switch was giving me the desired result). Resently I had few pcs that freaked me out - I changed everything that is responsible for the network and nothing - at last just changing the mcu gave me stable network.
so, the conclusion is that this phone is c.r.a.p
b.r.