Home
Back
Antenna Length Formula:
| From: | To: |
The antenna length formula calculates the optimal length for a dipole antenna based on the operating frequency. The formula L = 468 / f provides the length in feet for a half-wave dipole antenna at the specified frequency.
The calculator uses the antenna length formula:
Where:
Explanation: The constant 468 represents the speed of light factor adjusted for typical antenna wire characteristics, providing the half-wave length for optimal resonance.
Details: Proper antenna length is crucial for optimal signal transmission and reception. An antenna cut to the correct length for the operating frequency maximizes efficiency and minimizes standing wave ratio (SWR).
Tips: Enter the frequency in MHz. The value must be greater than 0. For best results, use the center frequency of your intended operating band.
Q1: Why is 468 used in the formula instead of 492?
A: The 468 factor accounts for the velocity factor of typical antenna wire, which is approximately 95% of the speed of light, making it more accurate for practical antenna construction.
Q2: Does this formula work for all antenna types?
A: This formula is specifically designed for half-wave dipole antennas. Other antenna types (quarter-wave, full-wave, etc.) require different calculations.
Q3: Should I include the units in the calculation?
A: The formula automatically returns length in feet when frequency is entered in MHz. No unit conversion is needed.
Q4: How precise does the antenna length need to be?
A: For most applications, precision within 1-2% is sufficient. The antenna can be slightly trimmed after construction for optimal SWR.
Q5: Can this formula be used for both transmitting and receiving antennas?
A: Yes, the formula works equally well for both transmitting and receiving dipole antennas operating at the same frequency.