Hero signal strength

Righty o, i had a TG01 and using that as a wireless modem was ok, I managed to download 180 mb in about 90 mins or so. Ive since got a HTC Hero and when i use this as a modem i struggle to get decent net connection. At most i get approx 5kbps as opposed to the 100+ kbps with the tg01. Iam sat in the same room as before nothing has changed but cant work out why i suffer with a poorer speed, is there anyway i can change the radio on the phone for another version? I have done a software upgrade when i got the phone so I cant change that.

Regards

Mark.