Dipole Antenna Calculator

The Formula

The formula for calculating the length of a dipole antenna is:

\[Total Length (meters) = \frac{143}{Frequency (MHz)} \times Velocity Factor\]

Where:

• Total Length: The full length of the dipole antenna (in meters)
• Frequency: The operating frequency of the antenna (in MHz)
• Velocity Factor: A coefficient (typically between 0.9 and 0.95) that accounts for the slower propagation of waves in wire compared to free space

Calculation Steps

1. Determine the operating frequency (in MHz) and velocity factor
2. Apply the formula: Total Length = (143 / Frequency) * Velocity Factor
3. Calculate the arm length by dividing the total length by 2

Example Calculation

Let's calculate the length of a dipole antenna for 145 MHz with a velocity factor of 0.95:

\[Total Length = \frac{143}{145} \times 0.95 = 0.936 meters\] \[Arm Length = \frac{0.936}{2} = 0.468 meters\]

Visual Representation

This visual shows a dipole antenna with its calculated total length and arm length based on our example calculation.