My thanks to the entire group for the excellent responses (mostly :^)
) on my problem. It was only yesterday that I finally had opportunity
to address it.

The RF on the fish line did not work.... just did not seem to couple
and radiate. However, a very very simple procedure ( one of you
mentioned this ) did work. I had my wife pull and push the fish tape
back and forth while I listened very closely for any sound of it thumping
against the end of the pvc at the far end. It worked. I did not
actually hear it hittingi the duct tape, but I did hear it as it moved
back and forth on the last sweep at the end. It was only about 8 inches
under the surface of the sand ( much less than I had thought ) and was
located farily easily.

You guys came up with a plethora of solutions which would have been fun
to try.... one of the reasons I posted the question to this group,
even though a bit off topic.

To answer one question, the PVC will only be used for electrical, not
antenna, so the 3/4" is quite sufficient for my needs.

Again, thanks to all. I won't forget some of these methods suggested.

Ed K7AAT