It's been more than forty years since I'd fooled with a Navy discone-discage
but I seem to remember the cage was used below 10 MHz and the cone, above 10.

Each had a remote controlled couple at its base. There was a remote controlled
tuner at the transmitter end. Of course, the antennas were used for transmit
and receive.

Which reminds me... The third main antenna on the cruiser I worked on was a
standard Navy 33-foot whip, mounted horizontally from the top of the
wheelhouse. It was the radiator or "exciter" and the ship's deck was the
reflector. It worked fine on HF. The distance of the whip above the deck was
quite great. Else I might try that, or similar, by supporting a wire above my
65-foot metal mobilehome. Oh, if I only had the energy these days to still do
things like that.

Bill, K5BY