I've read (but not tried) that what works is a verrry loooong wire strung up like between trees or in a barn.
If there is some distant broadcast (maybe overseas) that you want to receive you can definitely build a very efficient antenna system for that broadcaster's frequency. Be prepared to shell out well over $10,000 for this.
Also interested in what kind of equipment broadcasters use - it's some off the shelf stuff ?
Although I think you can do it cheaper - people have had a lot of success with a Beverage antenna. It takes up a lot of space though!
The same guy also owns an airport from what I recall.