1. A wire should be as good as tubing. 2. Use at least 16 radials 30' long. You won't get much if any improvement by making them longer and zig-zaging. Probably 32 would be a little better, but it's not worth it to use more.
3. Do NOT put it against the trunk! The farther away from the tree the better. Trees do absorb vertically-polarized RF to some extent. 4. You would most likely get improved efficiency from a remote tuner at the base of the antenna than from a tuner in the shack. On some bands the SWR will be quite high on the run from the tuner to the antenna. On 12/19/2010 4:21 PM, Lew Phelps K6LMP wrote: > I'm currently running my K3-10 into a 40 meter horizontal loop antenna, > mounted on my > roof about 35 feet above ground. It's impractical to use on 80, and has a > very high > angle of radiation on 40 and 20 meters. > > So, I'm thinking of replacing it with a 43' wire vertical. Yes, I know it > needs a > wide-range tuner, because it's non-resonant on any ham bands. I already have > that. And > I know that it needs a 4:1 balun. I can make that. > > I have three questions for the group. > > 1. Is there any reason to expect that a wire vertical will perform > significantly > differently than one made from aluminum tube (e.g. 2" OD at base)? EZNEC > modeling > shows a slightly lower gain for a wire antenna, but not significant. Is this > borne out > in real life? > > 2. The available grassy yard space where the antenna would be installed would > permit a > maximum straight-line radial run of approximately 30 feet, well under the > desired > length of 58 feet for operation on 80 meters. Would it affect antenna > performance if > the radials were laid out in a series of Z jogs rather than in straight lines? > > 3. The antenna would be suspended from a large sycamore tree. Will it make any > difference in performance if I run the vertical right up the side of the > trunk, as > contrasted with suspending it from a limb at some distance (e.g. 5 - 10 feet) > from the > trunk? > > Thanks, > > Lew K6LMP -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
