why can't USA just lock onto his radio signal and fire a couple of missiles and take him out?
Why would US want to hit politician like him ????? He was, at one time, a contender for PM of Pakistan. And he does not emit any "radio signals" .... perhaps you are getting your "maulanas" mixed up. This is Maulana "diesel"
The maulana with "radio signal" is Maulana Fazlullah ... he is the "Radio Mullah" .... again this guy has not done anything to US troops. In any case government of Pakistan has come to an understanding with his group in Swat.