Home
Back
Quarter Wave Antenna Length Formula:
| From: | To: |
A quarter wave antenna is a type of monopole antenna that is one quarter the wavelength of the frequency it's designed to transmit or receive. It's commonly used in various radio communication applications due to its simplicity and effectiveness.
The calculator uses the quarter wave antenna formula:
Where:
Explanation: The formula calculates the optimal length for a quarter wave antenna based on the operating frequency. The velocity factor accounts for signal propagation speed in different materials.
Details: Quarter wave antennas are fundamental in radio communications, providing a good balance between size and performance. They are used in various applications including AM/FM radio, mobile communications, and WiFi systems.
Tips: Enter the frequency in Hz (e.g., 1000000 for 1 MHz). The velocity factor defaults to 1 (free space) but can be adjusted for different materials (typically 0.66-0.95 for coaxial cables).
Q1: What is the velocity factor?
A: The velocity factor represents how much slower radio waves travel in a medium compared to the speed of light in a vacuum. It varies based on the dielectric material used.
Q2: Can I use this for any frequency?
A: Yes, the formula works for any radio frequency, but practical antenna sizes become very large at lower frequencies and very small at higher frequencies.
Q3: Why quarter wavelength instead of full wavelength?
A: Quarter wave antennas are more compact while still providing good performance. They use a ground plane as the other half of the antenna system.
Q4: How accurate is this calculation?
A: The calculation provides the theoretical length. Actual construction may require slight adjustments for optimal performance based on the specific environment and mounting.
Q5: What units should I use for frequency?
A: The calculator expects frequency in Hertz (Hz). You can enter 1000000 for 1 MHz or 1000000000 for 1 GHz.