Verticals can be very efficient with just one elevated radial. Of course, such an antenna can be viewed as a dipole, so yes, dipoles are good! Is it better to have one leg of the dipole horizontal at 8 ft or vertical? My experience is that on dry and rocky ground horizontal is usually better, but only by a little, and not by anything close to 30 dB. There are also big differences in performance depending on distance and skip angle etc, so the vertical can sometimes work better for an individual path. Where the ground is wet with salt water I believe the vertical configuration will win by a good margin (I have no personal experience though), and many real-life situations may fall somewhere in between. A good loading coil doesn't affect efficiency much as long as the antenna leg is shortened by less than 50%. On the upper bands it is rather easy to avoid loading coils altogether, either in homebrew configurations or using the extension rods offered by the commercial makers. However, if a horizontal dipole leg is shortened by a coil, it is still the same height. If a vertical is shortened, it will have less average height, giving it further disadvantage versus the horizontal, but again subject to great variations depending on the surroundings and propagation path. It doesn't hurt to have the capability to set up alternative configurations to find out what works best in a given situation.
73, Erik K7TV ----- Original Message ----- From: "Mike Morrow" <[email protected]> To: <[email protected]> Cc: <[email protected]> Sent: Sunday, July 12, 2009 7:19 PM Subject: Re: [Elecraft] Antennas for K1 Field Use > That would be very inaccurate. HF vertical antennas for field use will > almost > *never* have a proper and effective ground system. Add to that the losses > of loading coils/traps, and one will very certainly find *at least* a 30 > dB difference, > receiving and transmitting, in side-by-side comparisons between the > vertical and > any simple wire resonant dipole. That means six S-units. That means a > one watt > signal into the dipole will be better than 1000 watts into the vertical! > > The installation of a semi-effective ground system for the vertical would > require > multiple tuned counterpoise wires that are far more troublesome to employ > than > just using a simple resonant dipole. ______________________________________________________________ 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
