{"id":896,"date":"2026-06-06T11:36:50","date_gmt":"2026-06-06T15:36:50","guid":{"rendered":"https:\/\/registration.w2mmd.org\/wpregp\/?page_id=896"},"modified":"2026-06-20T16:01:18","modified_gmt":"2026-06-20T20:01:18","slug":"end-fed-half-wave-antenna-build","status":"publish","type":"page","link":"https:\/\/registration.w2mmd.org\/wpregp\/end-fed-half-wave-antenna-build\/","title":{"rendered":"End Fed Half Wave Antenna Build"},"content":{"rendered":"\t\t
\n\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"\"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t
<\/figure>\n

<\/p>\n

\u00a0<\/p>\n

The upcoming GCARC End-Fed Half-Wave (EFHW) antenna build project date is almost here!<\/h1>\n

The Saturday, July 11, session is full.<\/h1>\n

Space is still available in the Saturday, July 18, session.<\/h1>\n

The cost per seat is $60.00 for the basic 250W version, $67.50 for the 750W version, and $75.00 for the 1500W version.<\/h1>\n

<\/h1>\n

\u00a0<\/h1>\n

<\/p>\n

This build is a bit different from any that we have done before, in that each builder can select the band for which he\/she wants to build.<\/p>\n

The photo above is an actual unit built under this plan.<\/p>\n

<\/p>\n

This antenna project was originally intended to be an adjunct to the WSPR transmitter builds that we did a month or so ago. However, it was recognized that many members may simply want a nice moderate-power (or even high-power) antenna that is extremely simple to deploy. As a result, the design was modified to permit easy upgrade to 1500-watt capability.<\/p>\n

<\/p>\n

The $60 price tag, while maybe seeming high, is still considerably less than the similar antenna kit offered by ARRL. Even the 1500-watt version of our antenna will come in under the $80 price tag (plus tax and shipping) for the ARRL EFHW kit… and the ARRL version is certainly not rated for a kilowatt and a half.<\/p>\n

<\/p>\n

The heart of the antenna is the 49:1 impedance ratio transformer that connects the feedline to the radiator wire. This transformer is based upon an FT240-43 toroidal core (or two of them for the 1500-watt version) using heavy-build 14 AWG enameled magnet wire rated at 155\u00b0C. The transformer is enclosed within a 4-3\/4″ square IP-65-rated weathertight and UV-stable plastic enclosure in a dark grey color. The enclosure will incorporate an SO-239 connector for the feedline attachment, and 8-32 studs with wing nuts for the radiator wire and counterpoise. Internally, the toroid(s) will be secured to a custom-made anchor plate, which in turn will be secured to threaded bosses in the floor of the enclosure. Finally, the enclosure will be equipped with a ring bolt used for hanging the box. Several colors of wire are available for the radiator. The radiator wire will be terminated with a “dogbone” insulator to aid in tying off the radiating element properly.<\/p>\n

<\/p>\n

<\/p>\n

Give it some thought, and then if you decide that you can use such an antenna, sign up for the build by completing the form below…<\/p>\n

<\/p>\n

<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t