Thanks to all who answered my query about TDS. I'll give it a try. It's an old calculator/data collector. I hope all have a great Memorial Day.Thanks...

Memory card is 1MB GX, no battery in card.Thanks Bill

Thanks, Henry. I'll keep looking/researching. I'm working in Savannah on a road project and may try to contact Mr. Cadle. Perhaps he could shed some...

I am impressed that those stones have lasted these many years. Were you able to check the declination in 2013 and compare to original declination? Do...