Been there, ruined a shovel on an old clothesline anchor. I ended up renting a pipe and cable locator from the big box store. It was cheaper than a new tool and found a bunch of buried junk wire. The basic model won't find pure concrete, but it'll often pick up the metal posts or any wire still attached.

Well, @anthony_rivera solved it, but is a one-off number really that big a deal?

Feel your pain, man. That rule is gospel for a reason.

Ugh yeah @derekhunt, those airport guys are the worst. I paid like 80 bucks for a SIM that died after two days.

My old house in Phoenix taught me the same lesson as janag89, that math beats guessing every time.