1. What is a Folded Dipole?

A folded dipole is a variation of the standard dipole antenna that provides wider bandwidth and higher impedance (typically 300Ω) compared to a simple dipole. It consists of two parallel dipoles connected at their ends, forming a loop.

2. How Does the Calculator Work?

The calculator uses the folded dipole equation:

Where:

• \( L \) — Length of the folded dipole in feet
• \( f \) — Frequency in MHz
• \( \text{width factor} \) — Correction factor (typically 0.95-1.05)

Explanation: The equation accounts for the velocity factor of electromagnetic waves in the antenna conductor and the physical spacing between conductors.

3. Importance of Length Calculation

Details: Accurate length calculation is crucial for proper antenna resonance at the desired frequency. An incorrectly sized antenna will have poor performance and impedance mismatch.

4. Using the Calculator

Tips: Enter frequency in MHz and width factor (default is 1.0). For most applications, a width factor between 0.95 and 1.05 works well.

5. Frequently Asked Questions (FAQ)

Q1: Why use a folded dipole instead of a simple dipole?
A: Folded dipoles offer wider bandwidth, higher impedance (better matching to 300Ω feedline), and are more mechanically robust.

Q2: What materials should I use to build a folded dipole?
A: Copper or aluminum tubing works well. The spacing between conductors should be about 1/50th to 1/100th of the wavelength.

Q3: How does the width factor affect performance?
A: The width factor accounts for the velocity factor and spacing between conductors. Values slightly less than 1.0 compensate for end effects.

Q4: Can I use this for VHF/UHF frequencies?
A: Yes, the equation works for all frequencies, but at higher frequencies, construction tolerances become more critical.

Q5: What's the typical impedance of a folded dipole?
A: Approximately 300Ω, compared to 75Ω for a simple half-wave dipole.