Ed:

I would sure try different orientations first. Having to use a reflected
signal is indicative of a poor path, of course. See if there is another
direction which gives more reliable stereo decoding, which may not
necessarily be the strongest signal. Stereo decoding is indicative of the
fewest multipath contributions, and may be in a different direction
entirely. Also, try changing the polarization of the antenna, although
making it vertical will be difficult, as running a mast and feedline in the
same plane as the elements will pretty much destroy the performance. It
will likely need a mounting which is mechanically impractical in your
situation.

--
Crazy George
Remove N O and S P A M imbedded in return address