This has been an excellent discussion on the 43 foot vertical. I have one installed in my back yard (DX Engineering). Very happy with it overall. It's been an excellent performer on 20 meters, and good on other bands; I'm a casual DX-er, but have worked 5 continents SSB with the 12 watt output of my barefoot K3.
Phil Salas had an excellent article in QST a year or so ago describing how to install switchable loading coils at the foot of the antenna, to mitigate low-band problems. I match my 43 footer with a home-brew tuner -- a fully switch-configurable L-tuner that has a 27 µH variable inductor, 600 pFd of air variable capacitance, and two additional 600 pFd fixed caps that can be switched in parallel with the variables to provide up to 1800 pFd capacitance. With this tuner, I can get a match across the full spectrum of all bands except 160 meters, where I can get below 2:1 only in the top 200 khz (without Phil's loading coils). I recognize, of course, that the line losses are severe on the low bands, even with a run of only 60 feet of 9913 Belden coax. (A more detailed description of this tuner project is available at http://n6lew.us, if anyone's interested.) For the high bands, I already have both a home brew 6 meter j-pole and a three-element quad. I'm currently working on construction of a 17-15-12-10 meter hexbeam, to overcome the high radiation angle of the vertical on the higher bands. (Although most published hexbeam designs also in include 20 meters, I'm omitting that band from my project to reduce antenna size for visibility reasons, and because the vertical performs quite well on 20, as noted. Overall, I'd say that the 43 foot vertical pairs up well with the K3, although I can't speak to the ability of the Elecraft auto-tuner to match the load on all bands. The simple L-tuner does so quite nicely. Lew Phelps N6LEW Pasadena, CA DM04wd Elecraft K3-10 Yaesu FT-7800 l...@n6lew.us www.n6lew.us On Sep 3, 2013, at 5:23 PM, Jim Brown <j...@audiosystemsgroup.com> wrote: > YES! You've hit the nail beautifully on the head, Ron. I just finished > preparing slides comparing a 43 ft ground-mounted vertical with a good radial > system on 20M, 15M, and 10M with a classic ground plane at 30 ft and vertical > dipole with a base at 30 ft for those bands.Looking at performance below > about 15 degrees elevation, the three antennas are roughly equal at the low > angles on 20M, but both the ground planes and the vertical dipole blow the 43 > ft vertical away on 15M and 10M (the difference ranges between 6-8 dB, > depending on ground conductivity). > > The practical problem with sticking a ground plane on your roof is that it > needs at least two radials per band, but there are several multiband antennas > for those bands configured as vertical dipoles that work well without > radials. That's the basis of my earlier statement that a roof-mounted > well-designed multi-band vertical dipole is a far better antenna above 20M > than the 43 ft vertical. > > 73, Jim K9YC > > On 9/3/2013 2:28 PM, Ron D'Eau Claire wrote: >> An interesting point I noticed modeling a 43 foot vertical was that, while >> on 10 meters the main lobe is up around 50 degrees, the "gain" at low angles >> is similar to a 1/4 wave "ground plane" antenna cut for 10 meters. That's >> because the longer antenna has significant gain over a 1/4 wave antenna so >> the amount of radiation down at the lower angles is about the same as a 1/4 >> wave. >> >> That's for a ground mounted 1/4 wave on 10 meters. Ideally you want to raise >> the 10 meter vertical at least 1/2 wavelength - roughly 16 feet - then you >> get much better low angle radiation from the 1/4 wave because the ground >> absorbs much less of the lowest angle radiation. Installed that way, the 1/4 >> wave shines over the 43 footer. Also, of course, there is less interference >> with the signal by foliage, buildings, etc. > > ______________________________________________________________ > 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
