I suspect not. It isn't the concrete so much as all the steel embedded in it. In any case, it has to be a local solution. It takes a minimum of two to three weeks to receive a package here, and I need something today or tomorrow.

I have found a way to run a wire outside the house involving drilling a small hole through a bug screen, so I think I'll start looking into a doorbell-type solution. 30 feet of wire, a buzzer, a button, probably a transformer (I don't think the buzzer will be running at 110 volts, will it?) and maybe I can put something together.

tanstaafl.