The extended double Zepp (EDZ)
A Double Extended Zepp is a 3 db gain antenna .
The extended double zepp or EDZ is one of the most successful wire antennas ever developed. It has a bit of gain and if high enough can be a great antenna on the HF bands.
The 'Zepp' name came from the use of the antenna on Zeppelins in the 20's and 30's. Its a non resonant antenna which provides arounnd 3dB of gain over a dipole if mounted at the right height. Around 0.6 of a wavelength is ideal .