60 + j19 does seem off. Is this ground mounted or with elevated radials?
An EZNEC free-space model reports *36 +j227* at 1800kHz.
On perfect GND it reports 166 +j306 ohms.
10' above 0.005/13 GND it reports *37 +j262* ohms with resonance at 1510kHz.
Dave KH6AQ
On Wed, Dec 9, 2020 at 11:32 AM Jim Brown <jim@audiosystemsgroup.com> wrote:
> On 12/9/2020 12:00 PM, wi6x.73@gmail.com wrote:
> > My gut tells me the 60.25197 + J 18.63926 ohms impedance is to high, but
> I don’t have enough experience to know if what what I am doing is correct
> or not. I’m a neubie, at EZNEC and 160m.
>
> Those numbers tell you that the antenna is resonant below the band, and
> the dimensions also show. It's a common trick to tune the antenna low so
> that R is 50 ohms and X is inductive; we can then tune out the
> inductance with series C. I'm using this technique with my Tee vertical
> for 160M.
>
> Feedline loss on 160M is pretty low unless the line is pretty long, so
> if your rig or power amp will drive it, I wouldn't worry about it.
>
> Another important observation. Four radials isn't enough of a
> counterpoise unless they are well elevated -- N6BT, who's done lots with
> verticals and is a fine antenna engineer, says at least 16 ft. A lot
> of the R in your model could be ground loss. If those radials are
> on-ground, you need a LOT more than four; they don't need to be any
> specific length or even close to the same, but 100' is pretty close to a
> quarter wave (thanks to soil modifying their VF), and more copper on the
> ground is better.
>
> Also, soil parameters strongly affect that loss component -- try to
> learn what your soil is like, and plug those parameters into the model.
> In the soil parameters window, right click on the entry screen to get a
> list of them.
>
> Here are slides for a talk I've done at Pacificon, Visalia, and to
> several clubs. It's mostly about antennas and counterpoise/radial
> systems. No original work, just summarizing a lot of great work by others.
> http://k9yc.com/160MPacificon.pdf
>
> 73, Jim K9YC
>
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