[klondike98]

You can leave the connection labeled "ground" unconnected to anything. Sometimes folks will connect it to a cold water pipe if you still have copper pipe, or to an earth ground rod, or to the ground in their electrical system. This ensures the chassis is at ground potential and can sometimes help reduce unwanted electrical noise.

The connection labeled "antenna" is where you connect that 20 foot wire. You do not connect the antenna and ground together.