Calculator To Design Your Own Dipoles And Inverted "V"
Most hams are familiar with the center fed, half wave dipoles and inverted "Vs" that are very popular and easy to build. This formula will give you a starting point to make these antennas. There are several factors that affect the resonant frequency of any antenna. Some of these factors are: the height above ground, the diameter of the wire, nearby structures, the affects of other antennas in the area and even the conductivity of the soil.
If you've ever used some of the other antenna design programs you may realize that the formula for these types of antennas vary from about 476/f MHZ to 490/f MHz depending on the band and the height above ground!
Fortunately there is a standard formula that can be used as a starting point in your design. For a center fed, wire dipole, this formula is 468 / frequency in megahertz. It is always better to cut the antenna a few inches longer which would allow you to trim the antenna in order to obtain a 1:1 match.
The inverted "V" has always been about 3 - 5% shorter than a dipole at the same frequency. Use 4% as a constant in the calculation.
This Java Script uses the standard formula, 468 / f MHz to calculate dipole lengths. You may change this number if you know of a better number to try.
Enter the formula for the antenna calculation
Percent smaller for the Inverted V
Your dipole's total length is
Each leg of the dipole is
Your Inverted V's total length is
Each leg of the Inverted V is