Worth a try for sure. But Broncos are not known for their stellar reception no matter what you do. Not that they're lousy, just not as good as most other vehicles.
Mine has always had just half-way decent reception, but I live in a signal rich environment here in the SF bay area too.
Most of my older cars were better, but still not as good as my newer ones. My gold-standard is the '96 Chevy truck I had for awhile. That guy would pull in stations from everywhere! My '04 Buick is almost as good, but both are better than all the rest I've owned.
Had an '89 Cadillac that was extremely good for it's age, but still could not hold a candle to those other two.
My worst "newer" car was a '99 Lincoln Towncar that had, for a modern car anyway, very crappy reception. Did install one of our #6528's and it did improve, but there were not many places to cleanly route it either. Got it up and out of the way, but was a little vulnerable in that car. In a Bronco I'm thinking there are more places to mount it (hard to believe that!) but with more metal than plastic, not sure where the best place is yet.
Since I'm not daily-driving mine right now, I have not had a chance to experiment with different locations or routing of the ribbon on an EB. Would love to find out it would work tucked up inside a hard top though!
I would also be interested to hear reports from anyone that's completely re-wired their EB's with new harnesses, and how it's effected the working of the radio. If at all.
Good luck.
Paul