Gonzo wrote:
Anybody ever tried connecting both sections of the tube together and
using this device on HF instead of VHF? Its cheap and is good for 100W
max output with 1kV anode potential


Yes, the Amperex 5894 tube (equivalent to the Mullard QQV06-40A)
was used in the Eldico SSB-100 series of 100W output HF transmitters,
which first appeared in 1956.

73,
Ed Knobloch