RCA ANT806 not cutting it!

[Boysterload]

So I bought an RCA ANT806 (http://tinyurl.com/buahpmt) this past spring and it has been pretty good. Some channels come and go and reprogramming the TV after a few days will bring them back. It is sitting on top of the chimney above the 1st floor roof and is about 40 feet from the street. The most annoying problem I have is when a car passes by, the TV goes black for a couple seconds. Is this some kind of reflection or something? The antenna is parallel to the street and am not sure what direction to put it. I live in ZIP code 13090 and the most important channel for me is 43 which is about 17 miles away. There are no other restrictions in the area (except for a tall tree bout 25 feet in front of it). All houses are no more than two stories in the area. The chimney has a metal cap over the furnace vent and is about a foot behind the antenna. RG6 cable and compression style fittings used with coax seal spooge around it. Cable is about 40 feet long. Any issues with running it through a surge protector? Thanks everyone!