Hi Mike, your inverted-J in EZNEC shows a radiation resistance at 1850kHz of 10 ohms. It is resonant at 1800kHz.
With the 50' vertical wire removed it is resonant at 2.7MHz and has a radiation resistance at 1850kHz of 11 ohms. Dave KH6AQ On Mon, Jan 11, 2021 at 10:52 AM Mike Smith VE9AA <ve...@nbnet.nb.ca> wrote: > Has anyone modeled an inverted J on 160m ? (almost an inverted U, really) > > > > I currently have only one left (the other half of my 2-el array blew down > and I've been lazy to replace it) and it "works" but not as good as it > could > I think if I had better supports (ie: taller trees, wider yard). I am > quite > constrained on my property boundaries, so it goes up crookedly and also at > a > slight angle about 60', over maybe 35'in broad arc and then nearly straight > down vertically 40', with the far end maybe only 10' off the ground (just > like an inverted J or U). > > It has 2 full size 1/4wl radials 180* apart raised up about 6' off the > ground. The radials are perpendicular to the direction the far end of the > vertical is headed..which is to say, the 'vertical' is not directly above > any part of the radials. > > (a little bit like an Aki-special but not nearly as 'good', hi) > > > > What concerns me MOST is the far end is mostly vertical on its way down and > it being barely off the ground at the far end. > > > > I can't do anything now that there's a foot of snow down in the woods > with > lots of rocks sitting right on top of the ground (too dangerous to > walk.especially on a bit of slanted ground,) however if I believed I could > do better by keeping the far end up off the ground some more, I might > re-route it somehow in the spring. Because of the lack of trees I doubt I > could get anything resembling a true inverted L, but I might be able to > zig-zag the far end here and there in the tree tops and some branches on > its > way back to earth a little bit to keep the far end away from the ground > some > more. > > > > Has anyone done any modeling of this type of antenna or even have anecdotal > evidence to share? > > > > p.s.- at times it works gangbusters..fr'instance I was testing it the other > day at 0.9watts (900mW) and it was still daylight here and about 45mins > before SS in New England and 2 skimmers (about 340miles/550kms away) picked > me up at 2-9dB..maybe that only means it's a cloud warmer? > > > > Tnx in advance. > > > > CU (all of a sudden) on Top Band. > > > > Mike VE9AA , NB > > > > > > Mike, Coreen & Corey > > Keswick Ridge, NB > > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector