1. What is a Half-Wave Dipole?

A half-wave dipole is the most fundamental antenna design, consisting of two conductive elements each one quarter wavelength long, making the total length a half wavelength. It's widely used in radio communications.

2. How Does the Calculator Work?

The calculator uses the half-wave dipole formula:

Where:

• \( f_{MHz} \) — Frequency in megahertz (MHz)
• 150 — Constant representing speed of light divided by 2 (approximation)

Explanation: The formula calculates the physical length of a half-wave dipole antenna for a given frequency.

3. Importance of Dipole Length Calculation

Details: Precise antenna length is crucial for optimal signal transmission and reception. An improperly sized antenna will have poor efficiency and impedance mismatch.

4. Using the Calculator

Tips: Enter frequency in MHz. The value must be positive. For best results, use the center frequency of your desired operating band.

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 150 instead of 300?
A: 300 would be for a full wavelength. We use 150 because we're calculating for a half-wavelength dipole.

Q2: Should I add extra length for tuning?
A: Yes, it's common to cut the antenna slightly longer and then trim it for best SWR.

Q3: Does this work for all frequency bands?
A: Yes, the formula works for any frequency, though practical construction becomes challenging at very high or very low frequencies.

Q4: What about velocity factor?
A: This calculation assumes free-space propagation. For wire antennas, you may need to multiply by 0.95-0.98 to account for velocity factor.

Q5: How do I calculate for feet instead of meters?
A: Multiply the result by 3.28 to convert meters to feet, or use 492/f instead of 150/f.