The original EDP antenna was an end end-fed wire matched with a parallel LC-circuit ("Fuchs-Circuit") and a counterpoise wire.. The description  was in the QST 1936.
 Beers, Y. (W3AWH): An Unorthodox Antenna, QST (1936), Heft 3, S. 32-33
The picture above shows the "new W3EDP antenna" which has an unsymmetrical wireman-feed ("Zepp") and a balun 1:4. At the end of the twinlead-feeder a feedpoint impedance in the range of 200-500 Ohm with some complex part +/-j X Ohm. The Balun 1:4 gives impedances, which can be matched by the built-in ATUs of the most transceivers. I have tested the antenna from 6 m to 80 m with a coax length of 12 m H-155 and the IC-7400, the TS-590 and the TS-480SAT. The losses are negligible and the antenna is working quite well in the praxis.
If you have matching problems you can change the length of the coax cable and try it again.
The construction of the 1:4-balun. 7 turns bifilar wound on FT140-43 core, for high power use FT240-43 (Amidon) or Fair-Rite RG43 (part number 5943003801) core.
The insulator at the feeding side of the W3EDP antenna.
Left is a non cunducting rope for mounting, right is the antenna wire.
Here are some pictures of Bojan, YT2SMS, with homemade feedline and an other Balun type: