Suggestions for FM Antenna Mounting

Hi All,

I recently got my MD ST-2 omnidirectional whip antenna mounted outside near the top of the roof and it's working pretty well overall. However, I'm now able to just barely pull in a couple stations that I would like to get more cleanly. (Couldn't get them at all before, so yes, I'm being greedy here.) A couple questions:

1) The roof is metal. Would mounting the antenna a few feet higher make any significant difference (by getting it away from the roof)? Would mounting the antenna to the metal flashing (i.e., grounding the antenna's base to the roof) help? If I want to put it on a tower or high pole, how much improvement might there be? I live on top of a hill already, so unless there is an issue about the ground being in close proximity, I'm not sure it will help much. It's currently about 12 feet off the ground, so would say 20 feet help? 30 feet?

2) Are there any omni antennas that are significantly better than the ST-2? I doubt it, but thought I'd ask. I'm hesitant to go to a directional antenna because I get stations from a lot of different directions and I don't want to bother with a rotator.

By the way, tuner is an MD Etude. I've also tried an inline signal amplifier without any luck. It makes the signal a little stronger on the signal meter, but doesn't improve the audio quality at all. Thanks for the help.