Check into radiofence. Base unit plugs into an electrical outlet and the radius expands from 10 feet to 180 feet. No buried wires needed. The dog wears a collar just like the ones with the buried wire. With the radiofence, when the collar gets further away from what the base unit is set for, it beeps for a warning and if the dog doesn't come back into range it will deliver a zap. I have my base unit plugged into an outlet inside of my house with the largest perimeter set. My weimaraner will challenge the beeps and shocks, but my bulldog runs back to the front door with just a beep warning. Sure beats burying wires and it is portable, I can bring it to my camp and set it up and give them boundries there as well.