David, W.r.t. radials you may want to study the findings of Rudy Severns, N6LF at www.antennasbyn6lf.com. His findings have also been published in QEX (spread over several recent issues). Some of his findings in simplified bullet form: "A number of 1/8 wave radials will be better than half that number of 1/4 wave radials. At least until you have 32 or more radials." "Four is just not enough." The latter quote applies to radials on the ground. In contrast he confirms that four elevated radials work great. You really need to read it all, and you should certainly not assume that 1/4 wave radials on the ground are a good choice.
Personally I can testify that elevated radials can be very very much better than a poor ground level "ground". Years ago I had put up inverted L's for 80 and 160. I first tried feeding them against my existing safety ground system which consists of a number of ground rods; one the feed point, another at the electrical meter, a couple at my tower (an important tie-in to my station ground still to be completed). These are tied together with 4" wide buried copper ribbon, branches of which also extend to some far-away parts of the lot. Although I achieved a good impedance match, the received signal strength was incredibly poor. I then added two elevated 1/4 wave radials for each band, suspended under the eaves of the 1-story house, trees, and short poles attached to the fence. The impedance match was still very good, and the antennas worked very well indeed. I believe I would have had the same results with verticals. I also recall trying just a few 1/4 wave buried radials for a vertical way back in my youth, with poor results. I am now a big fan of elevated radials. If you decide to go with ground level radials, I suggest you perform a sanity check after you install them: Temporarily string up one or two 1/4 wave radials at a height of 10 ft or so, sloping one end down to the feed point. Compare the results from the temporary radial(s) with results from your radials on the ground. If the elevated radials work best, consider either making them permanent, or improving your other radial system by adding more radials, and possibly making them shorter. 73, Erik K7TV > In the near term I want to try out (experiment with) a 33' vertical. > At Frostfest this year I picked up 32' or so of fiberglass mast. I am > going to tape a wire to this that is 34' long, twist the mast to wrap > the slack up, much like a widely spaced helical. > > When setup at home, it would (eventually) have a good ground field > (would start out with 16 radials and work my way up to 60'ish). The > coax run when used at the house would be less than 40'. > > When setup for portable operation (connected to mount I have for my > trailer hitch, to use when parked) it would have 4 radials of a length > not yet determined and the coax run would be less than 20'. > ....... > Current plans are for ground mounting. I understand that as radials > go, more is better. The radials would be black insulated wire on, or > within 1" of the surface of the ground. They would not be cut to 33' > or less if the space was not available. > > I am curious on the experience of the group with a similar vertical, > tuner at the rig, and short coax run. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
