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Half Wave Dipole Length Formula:
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A half-wave dipole is the most common and fundamental antenna type in radio communications. It consists of two identical conductive elements such as metal wires or rods, which are bilaterally symmetrical. The total length is half the wavelength of the frequency of operation.
The calculator uses the half wave dipole formula:
Where:
Explanation: The formula calculates the physical length of a half-wave dipole antenna based on the operating frequency and the speed of light.
Details: Accurate dipole length calculation is crucial for optimal antenna performance, maximum radiation efficiency, and proper impedance matching. An incorrectly sized antenna will have poor performance and standing wave ratio (SWR).
Tips: Enter the desired operating frequency in Hertz (Hz). For best results, use the center frequency of your intended operating band. The calculator will determine the optimal physical length for a half-wave dipole antenna.
Q1: Why is the half-wave dipole so popular?
A: The half-wave dipole offers simple construction, good radiation pattern, and reasonable impedance (approximately 73Ω) that matches well with common coaxial cables.
Q2: Does the formula account for velocity factor?
A: No, this calculation provides the theoretical free-space length. For practical antennas, you may need to apply a velocity factor (typically 95-97% for wire antennas) to account for end effects.
Q3: How do I convert the result to feet or inches?
A: Multiply the meter result by 3.28084 for feet or by 39.3701 for inches. Many antenna builders prefer working in feet for HF antennas.
Q4: Can I use this for any frequency?
A: The formula works for any frequency, but practical construction limitations apply at extremely high or low frequencies.
Q5: What about multi-band or shortened dipoles?
A: This calculator is for standard half-wave dipoles. Multi-band antennas or electrically shortened dipoles require different calculations and loading techniques.