Do you remember the distinctive double-diamond broadcast towers in old radio literature?

Those are examples of the Blaw-Know design. There is one belonging to WLW that stands just off the interstate, near the old VOA installation north of Cinncinnati.

You may have seen it on your way to or from the Hamvention. This informative paper deals with both the mechanical and RF reasons for the unique design and much of it is contributed by broadcast engineers who happen to be hams.

(Thanks, Don N4KC)