Underground Fence Necessity

After experiencing the death of my neighbor's jack russell last month, I have gone through a complete safety check on mine. I seem to have go mad with protection. I padlock the gate when I'm gone and put her on a run so she can't dig out. It seems essential to me that I purchase a radio fence of some sort to prevent the impending danger she poses to herself. I would very much appreciate it if someone could tell me if they knew where to get an underground system inexpensively or if someone is selling one. Please email me at AJForsting@hotmail.com if you know of any place/one?