I have a question about radio frequency blocking. I recently purchased one of those invisable dog fences to keep the new puppy from becoming roadkill. Pretty basic install except when it came to "blanking" out an area for the dog to go in to and out of the area. The instructions said to run two loops and twist the wire from each loop to form a safe area for puppy to go in and out. This entails digging two trenches. I really don't want to do that! My question is this: What can I use to cover the wire that will block out the RF being emitted from the wire? I just want to "blank out"about a five foot section in front of the door. Any thoughts?