KN5L EFHW Unun

2 X FT114-43 4T:28T #22 - 49:1 Z Ratio

2450Ω Load

2700Ω Load

2 X FT114-43 4T:30T #22 - 56:1 Z Ratio

2700Ω Load

3300Ω Load

Winding Instructions

Optimized winding technique results with winding capacitance and leakage inductance canceling out.

Referring to the photographs above. Wind the four turn primary/secondary winding. Green wire in the photograph. Each wrap through the core equal one turn.

Solder the secondary wire to the primary/secondary wire. Red wire in the photograph. This will be the primary tap which is connected to the 50Ω transmission line center conductor.

Wind two turns of the secondary in the same direction as the primary/secondary turns.

Wind the secondary over the initial six turns. Crossing over the windings inside the core forming a winding per winding interlace. Wind on six interlaces turns.

Continue winding the secondary windings to the desired turn count.

Winding instruction photos

Antenna Measurement

  • Antenna Length = 34.1'
  • 56:1 Z Ratio Unun
  • 32' 4" RG-8X + 2' 7" RG-58A/U Type Coax
  • AA-54 Antenna Analyzer
  • OSL Calibration at Unun
  • Resonant Frequencies = 13.4 and 27.5 MHz
  • 13.4 * 34.1 = 457
  • 27.5 * 34.1 / 2 = 469

Temperature Rise Measurement

  • Fluke Temperature Probe with Fluke 87V
  • 14 MHz 20 Watts CW for 2 Minutes Temperature Rise = 18°F
  • 0.3 dB Core loss at 20 Watts = 1.3 Watt Core Dissipation

Series and Parallel Inductance Measurement

2 X FT114-43 4T:30T 3300Ω Load SimSmith Approximation

SS R1.ohms adjusted for -0.3 dB at 14 MHz


2 X FT114-43 4T:30T 3300Ω Load SimSmith Approximation
With Fair-Rite Complex Permeability Model

  • SS D1.file = SS compatible Fair-Rite Complex Permeability File
    found in SimSmith Groups.io Files section
  • SS D1.mui = Initial Permeability, μi
  • SS D1.H = Inductance at Initial Permeability, using AL value
  • VNWA File: 2xFT114-43-4T-30T-3r3k.s1p


D1 Text for Cut and Paste 
//Ferrite
$data=file[]; //SS Fair-Rite permeability file
mui;H;
$mup = $data.R;
$mupp = $data.X;
$Ls = H * ($mup/mui);
$Xs = 2*Pi * G.MHz * 1M * $Ls;
$Q = $mup / $mupp;
$Rs = $Xs / $Q;
Rp = ($Q^2 + 1) * $Rs;

A.Hr =  H;
R1.ohms= Rp;


EZNEC and SimSmith Models

Source connected to Wire 1


Unun + 35' RG-58A/U + Antenna Tuner System Loss Analysis