Topband: I need help proofing an Inverted L model I made please. 40’ x 143’, four 100’ radials, #14 wire.

[wi6x.73 at gmail.com]

Thank you everyone.

The radials as modeled have End1 Ground connection and no End 2 connection. Should they be connected to another wire?

             --------------- WIRES ---------------

No.          End 1   Coord. (ft)              End 2   Coord. (ft)       Dia (in)  Segs        Insulation
     Conn.      X       Y       Z     Conn.      X       Y       Z                         Diel C  Thk(in)
1       GND        0,      0,      0    W2E1        0,      0,     40       #14   17          1        0
2      W1E2        0,      0,     40              143,      0,     40       #14   17          1        0
3       GND        0,      0,      0                0,   -100,      1       #14   17          1        0
4       GND        0,      0,      0                0,    100,      1       #14   17          1        0
5       GND        0,      0,      0             -100,      0,      1       #14   17          1        0
6       GND        0,      0,      0              100,      0,      1       #14   17          1        0

I have a field of 100+ 70’ to 20’ #14 wire radials under my lawn that I will use. I stopped inputing radials in the model at four radials when my numbers seemed off. I’m using EZNEC Ver. 6 (NEC-4).

I do not have room for proper elevated radials. I only have room to elevate about six, and they could only be about 5’ above ground. 

I used Jim K9YC’s Pacificon 160 on Small Lots slideshow to get started with this antenna and his cookbook for the balun. Thanks!!!!!

FCC’s ground conductivity map indicates 15 millimhos per meter, and I’m on predominantly clay soil.

Transmission line is 75’ of RG213, so it is not an issue.

Thanks again for helping.

Jim WI6X

> On Dec 9, 2020, at 1:16 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
> On 12/9/2020 12:00 PM, wi6x.73 at 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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