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 <ve9aa@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
>
>
>
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