First, what type 8500 do you have? Is it an X50? Second, that V1 is
old. They didn't even test one in this series of testing:
http://www.guysoflidar.com/radar-det...rld-tests.html
1.7 correlates with versions in the 2.9 and lower range. A V1 that old is probably way out of tune. Plug in the serial number of the unit on the V1 website. I bethcha you're looking at a $200 tune.