Sorry I haven't responded earlier. The installer and L-3 finally got their heads together and concluded the the unit that was installed was defective. L-3 sent the installer a new unit which he installed in my airplane. The installer was able to do a lot of electronic testing on the ground to demonstrate the performance. As soon as they were finished with the replacement, I pulled the plane out of the hangar for the test flight and determined quickly that they had "fixed" something. I took my FAA test flight for my $500 rebate and passed easily. I received my check within 3 weeks. I've since take a good cross country flight (Charleston, WV to Pittsburgh) and the unit worked flawlessly. I was able to see adsb weather and traffic at 4000 feet (fairly remote areas).
Hence, after the initial problems (hard to believe I'd get a defective unit right out of the box), I am very happy with the L-3 ngt2000 and the installer (in Clarksburg WV)