The folded unipole is a unique antenna as it is grounded at the base and fed from the folds (drop wires).

There any many advantages to the folded unipole, providing greater bandwidth than series fed verticals, feeding the antenna from the drop wires raises the radiation resistance and improves efficiency.

This folded unipole is designed for 80 Meter,Electrically short at only 30 ft with 4-20ft top loading wires,

covering 3.5 to 4.0 mhz with SWR no greater than 1.3 to 1, No tuner necessary.

The disadvantge is that its more difficuilt to build, However for DX we need a vertically polarized antenna.