PT-04 operates on the 433MHz frequency band and RF602 operates on the 2.4GHz band.
Some say 2.4GHz will interfere with areas with strong wifi (wifi operates around 2.4GHz too) and **** up the triggering. That one im not too sure. Maybe users of rf602 can comment...
I have no issues with triggering it locations where theres a homewifi network environment.