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Half Wave Antenna Length Formula:
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A half wave ground plane antenna is a type of vertical antenna that uses a ground plane as a reflector. It consists of a vertical radiator that is approximately half the wavelength of the operating frequency, with several radial elements acting as the ground plane.
The calculator uses the half wave antenna formula:
Where:
Explanation: The formula calculates the physical length of a half-wave antenna element based on the operating frequency and the speed of electromagnetic wave propagation.
Details: Accurate antenna length calculation is crucial for optimal antenna performance, proper impedance matching, and maximum radiation efficiency. The half-wave length provides good radiation characteristics and impedance properties.
Tips: Enter the desired operating frequency in Hertz (Hz). The calculator will compute the optimal half-wave length for your antenna design. Frequency must be a positive value.
Q1: Why is the half-wave length important for antennas?
A: Half-wave antennas provide good radiation patterns, reasonable impedance matching (typically around 73 ohms), and efficient radiation characteristics.
Q2: What is the velocity factor in antenna calculations?
A: This calculator assumes free-space propagation. For practical antennas, you may need to apply a velocity factor (typically 0.95-0.97) to account for material properties.
Q3: Can I use this for different frequency units?
A: Yes, but ensure you convert your frequency to Hertz (Hz) before calculation (1 MHz = 1,000,000 Hz, 1 GHz = 1,000,000,000 Hz).
Q4: What are typical applications of ground plane antennas?
A: Ground plane antennas are commonly used for VHF/UHF communications, FM broadcasting, amateur radio, and mobile communications due to their omnidirectional radiation pattern.
Q5: How many radials should a ground plane antenna have?
A: Typically 3-4 radials are used, arranged symmetrically around the base of the vertical element at 120° or 90° intervals.