ARSB Technical Resource

Amateur Radio Antenna Calculator

Calculate practical starting dimensions for HF, VHF and UHF dipoles, ground-plane antennas, verticals, loops and J-poles using your desired operating frequency.

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Enter antenna details

Choose a design and target frequency.

Presets are calculation examples. Confirm permitted frequencies with current BTRC rules.
Example: enter 7.100 MHz for the 40-metre band.
Wire correction factor
95% is a common starting value. Installation conditions affect resonance.
Amateur Radio Society of Bangladesh ARSB Technical Resource • Club Call Sign: S21AHQ
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Calculated dimensions

Half-wave dipole at 7.100 MHz

40 m band
Half-wave dipole
Centre-fed wire antenna

Cut the wire slightly longer than the calculated value, install it in its final position, then trim gradually while checking SWR.

Construction and safety notice Calculated dimensions are starting values. Leave extra material, install safely away from power lines, and tune at the final location using an antenna analyser or SWR meter.

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Formula reference

Calculations use the free-space wavelength and the selected correction factor. Values are construction starting points, not guaranteed final dimensions.

Wavelength λ = 299.792458 ÷ MHz
Half-wave dipole Total = λ × ½ × factor
Quarter-wave vertical Element = λ × ¼ × factor
Ground-plane antenna Radiator + each radial = λ × ¼ × factor
⅝-wave vertical Radiator = λ × ⅝ × factor
Full-wave loop Perimeter = λ × factor
J-pole Long = λ × ¾ × factor
Safety and regulatory notice Antennas must be installed away from electrical power lines and with suitable lightning protection, grounding, structural support and RF exposure precautions. Operate only on frequencies and power levels permitted by your licence and current BTRC regulations.
Calculator Support Notes

Included antennas, tools and guidance

This ARSB calculator combines antenna-dimension calculations with practical construction information in one easy-to-read technical resource.

Supported antennas

  • Half-wave dipole
  • Inverted-V dipole
  • Quarter-wave vertical
  • VHF/UHF quarter-wave ground plane
  • VHF/UHF ⅝-wave vertical
  • Full-wave loop
  • J-pole antenna

Calculation tools

  • MHz and kHz frequency entry
  • Common VHF/UHF frequency presets
  • Metric and imperial measurements
  • Automatic amateur-band identification
  • Adjustable wire correction factor
  • Formula reference

Page features

  • Antenna diagrams and construction notes
  • Print-ready A4 results
  • Mobile-responsive layout
  • BTRC regulatory notice
  • Electrical and antenna-safety notice

Important: Calculated lengths are recommended starting dimensions. Wire type, conductor diameter, installation height, ground conditions and nearby objects can change antenna resonance. Always leave a little extra material and perform final tuning with an antenna analyser or SWR meter.

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