I agree with Dodgeman. In addition, high winds can cause sewer gas smells by pressurizing the septic system. The only way to eliminate it, is to raise the vent high enough so the smell is released up in the air, where it can dissapate. But it would be funny to have a tall pole in the back yard. The problem with the vent on the DF is its so low to the ground and the smell can travel horizontally.
Good Luck
Ray
Master Plumber