You and Jeff may know something I didnt realize about sealing. I
cant
imagine being able to make duct tape seal off the open end of a PVC
pipe with tuct tape, How much pressure can be sealed with the tape
on the side of the PVC? I would have expected the tape to have been
applied to prevent sand from entering. That wouldnt seal against much
air pressure.

For the record, I duct taped the end well, when it was initially
buried, in order to keep out sand and even water. It was applied well
enough to prevent any reasonable air pressure from moving it, in my
opinion. Duct Tape is awful sturdy stuff, and sticks quite well, too.

As I already said earlier, a bunch of you guys posted some excellent
ideas I could have used.... and I probably would have if my first simple
try with making noise with my fish tape hadn't worked.

Thanks again to all.

Ed K7AAT