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HamCalc

Interactive Smith Chart

Design impedance matching networks visually

Interactive Smith Chart
0.20.5125OpenShort

Load Impedance

Add Component

Matching Network

No components added. Add L or C components to build a matching network.

Results

Load Z:
25.0 +30.0j Ω
Final Z:
25.0 +30.0j Ω
Initial SWR:
2.87:1
Final SWR:
2.87:1

How to Use the Smith Chart

The Smith Chart is a graphical tool used to visualize impedance and design matching networks. This interactive version lets you add inductors and capacitors to transform impedance from a load to a target (typically 50Ω).

Getting Started

  1. Set Your Load Impedance: Enter the resistance (R) and reactance (X) of your antenna or load. The red dot shows this starting point on the chart.
  2. Add Matching Components: Use the dropdown to select series or shunt inductors/capacitors. Each component moves the impedance along specific paths on the chart.
  3. Aim for the Center: The goal is to transform the impedance to 50Ω (center of the chart). The green dot shows your final impedance.

Component Effects

  • Series L: Moves clockwise along constant-R circles (adds positive reactance)
  • Series C: Moves counter-clockwise along constant-R circles (adds negative reactance)
  • Shunt L: Moves along constant-G circles (admittance chart)
  • Shunt C: Moves along constant-G circles in opposite direction

Common Matching Networks

For most amateur radio applications, an L-match (one series and one shunt component) can provide a good match. The order depends on whether your load impedance is higher or lower than 50Ω.