These non-nuke density gauges are new to us as well, and we are considering purchasing one or two - I think our plan is going to be to use the nuke and the TDR units side by side for a bit to see how they compare in differing soil conditions before we make a firm move one way or the other.

Can you give a website for this product?
I am familiar with TDR for moisture determination and slope movement, but not for measuring density.

http://www.durhamgeo.com/testing/soils/compaction-mdi.html

This is from SINCO, relatively new.

Exactly what we are considering, dirtguy.

Never have even thought about using that since it takes too long to do each density. 5 to 20 minutes for one density test is way too long.

This has become an issue for our firm since we are expanding and it has been a major hurdle to get licenses for use of nuclear gages in other states.  We will be running trials with the TDR method for moisture-density measurements

If you want more information, I would recommend that you plan to attend TDR2006

There are continuing developments with this technology beyond measurement of soil moisture.

https://engineering.purdue.edu/TDR/TDR/TDR/Call_for_Abstracts.html