The antenna farms for these stations required a significant amount of real estate. Shortwave antennas are very large, with multiple antennas in different orientations to ensure good coverage of the ocean under different conditions. Geographically separated transmitter and receiver sites were required to avoid interference.
This antenna (one of the smaller ones at the transmitter site) is an inverted "discone" design. It provides nondirectional coverage over a wide range of frequencies.