I know of another one
It's not that big but not nearly so expensive, either. It's an old Western Union antenna (perhaps 40-50 feet in diameter) at the Paint Rock Valley Lodge and Retreat in Alabama (an interesting place filled with antiques). I saw if up close and personal during a family reunion last Labor day. The owner would be happy to sell it for much less than the $50K that your link showed. There used to be another one that he sold to an amateur astonomer serveral years ago.