HF SWR Plotter

Projected SWR across the HF band for a wire with a 9:1 or 4:1 unun into 50 Ω.

Wire length

Enter length in feet and inches (for example 28'6") or as decimal feet (for example 29.5). The model sweeps 3.0–30.0 MHz in 0.05 MHz steps with band overlays and exact SWR at common activation frequencies.

4WAVE packages ship with a 9:1 unun by default. Real-world SWR depends on height, ground, and surroundings.

Projected SWR

Press Plot SWR to generate the chart.

How to read this chart

  • Lower SWR is better for your radio and tuner stress.
  • Shaded bands show the US amateur allocation; orange dots mark POTA-style activation targets.
  • The table below the chart shows projected SWR at exact spot frequencies (7.025, 14.300, 28.480 MHz, and more).
  • For measured data from your deployment, use a portable antenna analyzer in the field.

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