1. What is Dipole Length?

The dipole length is the total length of a simple dipole antenna that's resonant at a specific frequency. The formula provides the approximate length in feet for a half-wave dipole antenna.

2. How Does the Calculator Work?

The calculator uses the dipole length formula:

Where:

• \( f_{MHz} \) — Frequency in megahertz (MHz)
• 468 — Constant representing the speed of light multiplied by the velocity factor and divided by 2 (for half-wave)

Explanation: The formula calculates the total length (in feet) of a half-wave dipole antenna that will be resonant at the given frequency.

3. Importance of Dipole Length Calculation

Details: Proper dipole length is crucial for antenna resonance and efficient radiation. An antenna that's the correct length for the operating frequency will have minimum SWR and maximum radiation efficiency.

4. Using the Calculator

Tips: Enter the desired operating frequency in MHz. The result is the total length of the dipole antenna in feet. For best results, the antenna should be slightly longer than calculated and then trimmed for minimum SWR.

5. Frequently Asked Questions (FAQ)

Q1: Why 468 instead of 492?
A: The value 468 accounts for the velocity factor of electromagnetic waves in a typical dipole antenna (about 95% of the speed of light).

Q2: Is this length for each side of the dipole?
A: No, this is the total length. Each leg of the dipole would be half of this value.

Q3: How accurate is this formula?
A: It provides a good starting point, but actual length may vary slightly due to environmental factors and conductor thickness.

Q4: Can I use this for VHF/UHF antennas?
A: Yes, the formula works for any frequency, though construction becomes more challenging at higher frequencies.

Q5: What about metric units?
A: For meters, use 143 / f_MHz instead of 468 / f_MHz.