So - i installed an aftermarket Alpine radio 2 years ago, never had good sat reception. Just swapped out the sat antenna, thinking it was perhaps bad. No better with drop outs.
Originally under the plastic coweling by the wipers, as suggested in other threads. Placed above the coweling, problem solved ! Then replaced under coweling, but this time with the top part Up, toward the sky. Seems as the antenna does not work upside down.
Arg. Oh well.