12m copper wire (or other suitable radiating element)
Up to 4 x 1m whip sections (dependant on frequency in use)
Tactical, HF net working
The most efficient surface wave antenna for frequencies of 4-6MHz as the wire can be adjusted to ¼ λ for the frequency in use
No good for frequencies below 4MHz as the antenna would be too long for the support
A vertical radiator is the most efficient surface wave antenna. It only has the above disadvantage because of the PU12 mast and the fact that, in practice, you cannot cut the 12m of copper wire every time you change frequency. If you can erect a vertical radiator that will always be a ¼ λ in length then you have achieved the optimum antenna for surface wave.