Static Build Up

Ok, first, create a ground line, you have to have one, you have a phone. Find where the phone is grounded to and emulate it. Then run a simple line into your house where you can create a central grounding point. Copper wire is your friend. Baring that bonding is the next best trick, make all the static have the same charge (grounding wrist straps will help) basically you are making the charges equal by having a link of metal to metal to make sure the same ground is the same charge. It is a trick they use in chemical plants to prevent explosions.

good luck.

PS Running a ground like this can also help with your two wire issue ... your safety may depend on it if nothing you have is truely grounded (except the phone).