W3EDP End fed (10-40m)
In 1936, Yardley Beers, W3AWH, described an empirically-derived antenna "designed by the writer's friend, Mr. H. J. Siegel, W3EDP." It consisted of an 84 foot radiator and a 17 foot "counterpoise." The design has lasted through the years. .
The W3EDP End-fed antenna is a classical antenna in our series of HS4 Legendary Multiband Wire Antennas. It covers 7 bands, 10-12-15-17-20-30-40m. Unlike typical antennas, this is a non-resonant, End-fed antenna. The performance characteristics are quite outstanding. The antenna consists of a single length horizontal radiating elements being driven at the corner-end feedpoint through a 450 Ohm slotted parallel transmission line (TL) of a pre-determined length. The principle of a W3EDP End-fed antenna utilizes the unique configuration of the TL to not only produce the required impedance transformation for taming the SWR to workable limits but also acts as a part of the antenna radiating structure which results in both horizontal and vertical polarization of the radiated energy.
This antenna does not essentially need an antenna tuner for proper operation however a 9:1 broadband Balun is required to transform the 450 Ohm feeder impedance to 50 Ohm unbalanced for further coax run.. The overall gain on all bands is good with adequate low angle radiation for great DX. This antenna is deployed at a height of 12m (40 ft.) above average quality ground and the design accounts for ground absorption losses, antenna wire insulation dielectric losses, other structural losses, etc.
The most important feature of this antenna is that it produces nearly omnidirectional azimuth pattern with rather good gain and moderate gain ripple on most bands which is practical for copying and working DX in all directions. However, the owner of this antenna will still need to find the optimum direction of the radiation lobe on each band to leverage the main lobe which provides maximum gain. This may be on either side of the default beam heading. It may either be achieved by experimentation during the process of familiarizing the antenna characteristics or by referring to the exhaustive set of specifications with graphics and gain map given below... Happy DXing!