I too use 17GA fence wire it's cheap and performs just fine. Additionally it can take pretty good tension with no effect. You can buy it at the farm supply stores for $7 a 1/4 mile US Also good for temporary radials. I keep a couple miles of spare stuff around. put down a few extra radials every now and then. When it's time to mow.. just pick em up and throw them away. Tom AE9B