Enter the frequency and velocity factor into the calculator to determine the appropriate element length for your J-Pole Antenna.
J-Pole Antenna Calculation Formula
The following formula is used to calculate the element length of a J-Pole Antenna:
Element Length = (Wavelength * Velocity Factor * 100) / 4
Variables:
- Element Length is the length of the antenna element in centimeters (cm)
- Wavelength is the distance between consecutive peaks of the radio wave in meters (m)
- Velocity Factor is a number between 0 and 1 that describes the speed of the wave in the antenna material compared to the speed of light
To calculate the element length, multiply the wavelength by the velocity factor, convert it to centimeters, and divide by 4.
What is a J-Pole Antenna?
A J-Pole Antenna is a type of omnidirectional antenna commonly used for VHF and UHF radio communications. It is known for its simplicity and efficiency in radiating radio waves. The antenna consists of a half-wave radiator and a quarter-wave matching section, making it suitable for various communication applications including amateur radio and emergency services.
How to Calculate J-Pole Antenna Length?
The following steps outline how to calculate the element length of a J-Pole Antenna using the given formula.
- First, determine the frequency at which the antenna will operate.
- Next, determine the velocity factor of the material used for the antenna.
- Calculate the wavelength using the formula: Wavelength = 300 / Frequency (MHz).
- Use the formula from above: Element Length = (Wavelength * Velocity Factor * 100) / 4.
- Finally, calculate the element length by plugging in the values.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
Frequency = 144 MHz
Velocity Factor = 0.