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Counterpoise wire length
Looks like I'm looking for a 1/4 wave. Thanks
-- SeeYaa Harbin Osteen KG6URO This is YOUR futu http://halturnershow.com/aztlan_caps.wmv - wrote in message ps.com... Harbin wrote: Counterpoise wire length. I've heard that it should be 1/4 wave, and then again I've heard it should be 1/2. Which is correct, or will they both work? The lowest impedance presented by a single counterpoise wire is when the counterpoise is resonant and 1/4 wl long electrically. When a single counterpoise wire is near 1/2 wl long and resonant, it has a very high end impedance. If the counterpoise is under a dipole or some other antenna just to isolate it from ground losses, a 1/2 wl long counterpoise or longer is best. If the counterpoise is used as a termination to allow forceing current into a Marconi antenna or an end-fed antenna, or used to provide a ground path for unwanted currents, it is best if it is 1/4 wl long. More counterpoise wires are always better, because the more you use the less critical length is and the lower loss is. There is of course a point where more won't help. With 1/4 wl wires, 50 or so placed radially are near perfect. Adding more won't make a noticeable difference. Once the counterpoise wires are .025 to .05 wavelengths apart at the widest points, adding more will generally not help. I use 100 200 foot long wires on one of my 160 meter verticals. On my other verticals I have 1/4 wl radials, and once I reached 40-50 radials adding more made no measureable difference at all. 73 Tom |
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