Duncan Carter wrote: > Even if you don't have space for a large radial field, you are apt to > do better with elevated radials, even one "radial" ( the lower half of > the dipoles) as I have. Putting wire in or on the ground is mainly > useful for keeping earthworms warm. To read a lively debate on this > subject which includes links to two excellent technical references, > see all three pages of: http://www.eham.net/forums/Elmers/237953
73, Dunc, W5DC > > Bob Cunnings wrote: >> And, if you don't have enough space for a radial field on the ground, >> try a vertical doublet, center fed with balanced line for multi-band >> operation. I've been using one for years which is 32 ft. tall and can >> be loaded easily from 30 meters to 15 meters. Much better for dx than >> my low dipole and the elevated feedpoint (at 16 ft.) seems to help >> overcome ground clutter (enclosing block walls etc.). The wire is >> supported by a 32 ft. telescoping fiberglass pole, with footprint less >> than one square foot! >> >> Bob NW8L >> >> On Mon, Dec 14, 2009 at 12:58 PM, Ron D'Eau Claire <[email protected]> wrote: >> >>> 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:[email protected] >> >> 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
