Total posts : 45366
I strongly advise you not to use a water pipe for a ground for safety reasons. Primarily, you do not know if it is grounded and you might create a shock hazard for yourself and anyone working on the system. Even if it is grounded, the hazard exists if it is disconnected for maintenance and the plumber could be injured.
I have no advice about your RF grounding. Perhaps you can contact Rangemaster for advice.