|Subject:||Re: [TowerTalk] Vertcal Dipole|
|From:||Bill Tippett <firstname.lastname@example.org>|
|Date:||Sun, 17 Oct 2004 16:10:30 -0400|
K0PYK wrote: >Has any made a vertical dipole (lets say for 20 meters) where it is end fed with coax.
Yes but why not use a simple LC matching circuit? The following circuits work best with a single 1/4 wl radial counterpoise in addition to the 1/2 wl radiator:
http://www.qsl.net/aa5tb/efha.html http://www.qsl.net/aa5tb/halfwave.html http://www.w0ch.net/field_antenna/field_antenna.htm http://www.arsqrp.com/ars/pages/back_issues/2000_text/0100_text/film.html
I built the latter faster than it took to read all the posts about this!
I've also tried using a Z-match tuner (Emtech ZM-2) to directly feed a 1/2 wl radiator (no radial) which worked fine. However, I wanted to eliminate any tuner for ultra-lightweight backpack operations.
Par Electronics offers the following series of End-Fed 1/2 wave antennas which require NO radial and NO tuner. I've been using the EF-20/40 which works very well with direct feed from my QRP rig. With the EF-20/40 plus KD1JV's AT Sprint 2, I have a complete 20/40 station including transceiver, battery, earphones, paddle and antenna (no tuner needed) that weighs ~1 lb total.
73, Bill W4ZV
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
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