So not much different than the G5RV with parallel feed line all the way to the tuner, no coax. Just fed off center at the 39% or 61% point instead of center fed. I wonder about losses in the tuner due to the imbalance but not having tested it I hold any judgement. Several articles in the literature of similar OCF antennas fed with parallel line. Basically all are non-resonant, so no worries about resonance on higher bands as with OCF , balun,coax fed antennas.
I used a 88 foot center fed with 2 lengths of RG 6 coax similar to what you are using. From Ecuador I worked the world with QRP 40 to 10 meters and with 50 to 100 watts on 80. Yes, a good antenna. I center fed it due to worries about loss in baluns with OCF antennas and the lack of commercial balanced line. Just a little loss from the RG6. Dr. Don W4BWS SKCC 81C K2 SN 163 On Mon, Sep 18, 2017 at 6:02 PM, Wayne Burdick <[email protected]> wrote: > Hi Marv, > > I didn’t measure the legs. My best guess, standing here by the shack > window using an antique brass monocular, is 55’ on one side, 35’ on the > other. This is the most satisfying thing about off-center-fed dipoles: > length generally isn’t critical. Close your eyes and clip, knowing that, > most likely, the ATU will do the rest. > > The installation was opportunistic, taking advantage of a back yard > gazebo, a Home Depot telescoping pool-cleaning pole, and a huge white oak. > Height at each end was determined by how high my son was able to climb > without the neighbors noticing. > > The experimental feedline, running under the house for half its length, > was more deliberate if not justified in the literature. At first I was > using 300 ohm mystery twin-lead scavenged from an installation of yore. But > given all the RFI sources I decided to try two lengths of LMR-400, taped > together every few feet, forming a sortof-balanced-shielded feed. Purists I > consulted ahead of time continue to be shocked at how well this works. At > the mast, the grounds are left unterminated. In the shack, the two center > conductors go to an Elecraft BL2 balun. The shields are soldered together > and connected to the BL2’s ground lug. > > There you have it: Wide tuning range, low noise, low-loss, and > theory-free. How it works is left as an exercise for the reader. > > Wayne > N6KR > > > > > On Sep 18, 2017, at 2:31 PM, <[email protected]> < > [email protected]> wrote: > > > > Wayne: > > > > > > > > In a previous post you mentioned your 90 feet long OCF dipole. Would you > > please elaborate on your antenna? Balun, leg lengths, how fed? > > > > > > > > Thanks, > > > > Marv > > > > KG7V > > > > ______________________________________________________________ > 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 > Message delivered to [email protected] > ______________________________________________________________ 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 Message delivered to [email protected]
