1. What is a Dipole Antenna?

A dipole antenna is the simplest and most widely used type of radio antenna. It consists of two identical conductive elements such as metal wires or rods, which are bilaterally symmetrical.

2. How Does the Calculator Work?

The calculator uses the dipole length formula:

Where:

• \( L \) — Length of each dipole element in meters (total length is 2×L)
• \( f \) — Frequency in MHz

Explanation: The formula calculates the length of a half-wave dipole antenna for optimal resonance at the specified frequency.

3. Importance of Correct Length

Details: Precise length calculation is crucial for antenna performance. An antenna that's too long or short won't resonate properly at the desired frequency, reducing efficiency.

4. Using the Calculator

Tips: Enter the desired operating frequency in MHz. The result shows the length of each dipole element in meters. For total dipole length, multiply by two.

5. Frequently Asked Questions (FAQ)

Q1: Why 143 instead of 150 (speed of light)?
A: The 143 factor accounts for the end effect - the velocity factor of electromagnetic waves in a conductor is about 95% of the speed of light.

Q2: Should I add extra length for tuning?
A: It's common practice to cut the antenna slightly longer than calculated, then trim it while measuring SWR for perfect tuning.

Q3: Does wire thickness affect length?
A: Thicker elements require slightly shorter lengths due to increased capacitance. The formula provides a good starting point.

Q4: How does height above ground affect the dipole?
A: Height affects radiation pattern but not resonant length significantly, unless very close to ground (less than λ/4).

Q5: Can I use this for VHF/UHF frequencies?
A: Yes, the formula works for all frequencies, though construction becomes more critical at higher frequencies.