I live in a very hilly region.
I'm not necessarily suggesting that you make any changes from your present set-up, but here's some brief antenna theory as food for thought:
The Tram 1480 is (supposedly) a high-gain antenna. Antennas achieve gain by compressing or focusing their pattern towards the horizon, at the expense of the higher angles. Think of the light from a normal light bulb (all directions) versus the flatter pattern from, say, car headlights.
Gain antennas are great for prominent mountaintop stations and areas where the surrounding terrain is essentially flat, but they can be a detriment in hilly locales since the flatter pattern cannot go very far without running into a hill. Because of this difference in antenna pattern between a gain antenna and a lesser gain/no gain antenna, sometimes a lesser antenna will work better since there is a greater opportunity for the signal to bounce around or reflect off the nearby hills.
All of this theory depends, of course, on the actual physical conditions at
your location, so I'm not suggesting that you tear down your antenna and put up a simple ground plane. That said, however, you might wish to experiment to see how a non-gain antenna might work from your location. I also live in a hilly area and I've found that a standard whip antenna on my truck seems to work better than one with high gain numbers.
