Dave, I agree. The reason I tried the safety ground was that it was there. The reason I mentioned it here was as an example of what not to do. BTW I later ran the inverted L with just one of the elevated radials with excellent results. There is definitely a point at which a ground radial system crosses from being poorer than one elevated radial (= half dipole) to being better, as radials are added. I suggest it is a good idea to know which side of that point one is at.
73, Erik K7TV ----- Original Message ----- From: "David Gilbert" <xda...@cis-broadband.com> To: "Erik N Basilier" <ebasil...@cox.net> Cc: "David Wilburn" <dave.wilb...@verizon.net>; "Elecraft Discussion List" <elecraft@mailman.qth.net> Sent: Saturday, May 16, 2009 1:23 PM Subject: Re: [Elecraft] OT - SteppIR Vertical and Elecraft Products > > That's a really bad comparison. A good safety ground has no relationship > whatsoever to a good radial field. They perform different functions, and > while a good radial field might also provide some safety benefits as a > distributed path for lightning protection, the reverse is rarely true. > There is also no assured correlation between a ground/radial system that > gives a decent impedance match and one that gives decent signal > performance. A little web searching will bring up several references on > both points. > > It is true, though, that a buried radial system requires more than just "a > few" radials to give decent results. I don't want to get into the > elevated versus buried radial argument since both have their place and > (properly implemented) both will work well, but if space permits the > installation of enough sufficiently long buried radials they have some > definite advantages. > > 73, > Dave AB7E > > > Erik N Basilier wrote: >> 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 >> >> > ______________________________________________________________ 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
