Design Your Own Dipoles And Inverted Vees
Most people are familar with the center fed, half wave dipoles and inverted vees that are so very popular. But did you know that there really is no exact formula for computing the length of these antennas? The problem is that there are several factors that affect the resonant frequency of any antenna (including these two types.) 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 played around with some of the antenna design programs you may realize that the formula for these types of antennas vary from about 145 / f Mhz to 149 / f MHz depending on the band and the height above ground!
Fortunately there is a
formula that can be used as a starting point in your design. For a center fed, wire dipole, this formula is 142.6464 / frequency in megahertz. Although, at my location I've
have had to shorten the antenna in order to obtain a 1:1 match.
At least in theory, an inverted vee should be about 5% shorter than a dipole at the same frequency.
This page uses the standard formula, 142.6464 / f MHz to calculate dipole lengths. You may change this number if you feel you know a better number to use as a starting point.
Enter the formula for the antenna calculation
Percent smaller for the Inverted Vee
Your dipole's total length is
Each leg of the dipole is
Your Inverted Vee's total length is
Each leg of the Inverted Vee is
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