A VHF Antenna Calculator is a tool used to calculate the correct antenna dimensions (length, spacing, etc.) for antennas designed to work in the VHF (Very High Frequency) range, which covers 30 MHz to 300 MHz.
These calculators are helpful because antenna performance depends heavily on its size compared to the signal wavelength. The calculator usually asks for the frequency (in MHz) you want to receive or transmit, and then it gives you the antenna element lengths.
For example:
- The wavelength (λ) is found by the formula:
λ=300fλ = \frac{300}{f}λ=f300
where f = frequency in MHz.
- A quarter-wave antenna length = λ ÷ 4
- A half-wave antenna length = λ ÷ 2
So, if you want to build an antenna for 100 MHz (FM radio band, inside VHF range):
- Wavelength = 300 / 100 = 3 meters
- Quarter-wave antenna = 0.75 meters (75 cm)
- Half-wave antenna = 1.5 meters
👉 In short, a VHF Antenna Calculator helps you design antennas correctly for VHF communication, ensuring better signal strength, clarity, and range.