Yes your inverted-vee has max gain at 90 degrees elevation, but you (editorial sense) still need to compare its gain in the direction of interest with a vertical (or near vertical) over the same ground and with a real-world ground system.
Wes N7WS --- On Tue, 12/15/09, Radio Amateur N5GE <n...@n5ge.com> wrote: > From: Radio Amateur N5GE <n...@n5ge.com> > Subject: Re: [Elecraft] antenna farm > To: elecraft@mailman.qth.net > Date: Tuesday, December 15, 2009, 12:40 PM > On Mon, 14 Dec 2009 11:58:26 -0800, > "Ron D'Eau Claire" <r...@cobi.biz> > wrote: > > Yes you did open the flood gate. Antenna opinions are > like noses. > Every one has one... > > As Ron say's, If you can't get a dipole up 1/2wl you > will be sending > most of your radiated output and receiving at high angles, > which won't > be what you want unless you plan to do a lot of local rag > chewing. > > Here's a real life test that I made: > > I have an 80m half sloper on my tower sloping from 38 feet > which does > pretty well working 360 degrees around (the tower becomes > the radiator > when using this type of sloper). A couple of weeks > ago I put an 80m > inverted vee up and compared the two. The inverted > vee could not even > hear the European signals, but could hear signals within a > few hundred > miles very well. The reason for that was because the > inverted V (at > 38 feet) was radiating the largest amount of energy > straight up at 90 > degrees (verified with EZNEC 5.0). > > 73, > > Tom, N5GE > > n...@n5ge.com > K3 #806 with SUB RX, K3 #1055, PR6, > XV144, XV432, KRC2, > W1, 2 W2's and other small kits > > 1 K144XV on order > > http://www.n5ge.com > http://www.swotrc.net > > >As Ken mentioned, height is an important factor in a > horizontal or > >semi-horizontal antenna. There's limited "gain" in any > direction at low > >angles unless the radiator is 1/2 wavelength above > ground. That's why most > >of us have to live with little directivity on the lower > bands. > > > >The option is to consider verticals. Unless you are > living on salt water (or > >atop a sheet of copper), or can make the vertical a > full 1/2 wave high, the > >vertical won't be as efficient as doublet or dipole, > but a vertical will > >produce typically much better signals at lower angles > of radiation than a > >horizontal antenna (under 1/2 wave high) and doesn't > require a huge > >'footprint'. Also you can phase multiple verticals for > directivity and even > >design them so you can use them for supports for > horizontal wires on the > >higher bands. > > > >You've probably noticed that 45 foot verticals are > being heavily promoted > >these days. That's an old design that is very handy for > limited space. It > >provides low angles of radiation on all bands up > through 20 meters where > >it's 5/8 wavelength high (on bands where it's more than > 5/8 wavelength the > >angle of the main lobe rises from the horizontal and > minor lobes appear at > >high angles). Down on 80 meters it's just a bit shy of > 1/4 wavelength. With > >a good ground system it can produce excellent results > down there and even on > >160 - especially when compared with the short, low (in > wavelengths above > >ground) antennas most of us are forced to use on those > bands > > > >Ron AC7AC > > ______________________________________________________________ > 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
