Calculations to Design Your Own Antennas

The standard ground plane antenna consists of a vertical radiator which is insulated and centered between 4 horizontal surrounding radials which extend out from the base of the antenna. Each radial is evenly spaced 90 degrees or so from each other around the vertical element.

Enter the formula for the antenna calculation (normally 234/f):

divided by Freq. MHZ

The vertical length is feet.

The 4 radials are each feet.

The halfwave vertical antenna consists of a vertical radiator which is fed from the bottom of the antenna. A matching device should be added between the antenna and the feedline if you wish to use coax.

Enter the formula for the antenna calculation (normally 468/f):

Switch to:

divided by Freq. MHZ

Your halfwave antenna's vertical length is

The cubical quad antenna is a four sided antenna, with each side a quarter wave length long. Several factors influence the performance of the antenna, such as :

Enter the formula for the antenna (normally 1005/f):

divided by Freq. MHZ

Your quad's total length is feet

Each of the 4 sides are feet.

The 5/8 wave antenna consists of a vertical radiator fed at the bottom of the antenna. A matching device should be used if you feed it with coax.

Enter the formula for the antenna (normally 585/f or 178.308/f for metric):

Switch to:
divided by Freq. MHZ

Your 5/8 wave antenna's Vertical element is:

Most familiar are the centerfed, halfwave dipoles and inverted vees that are so popular.

A basic formula for these types of antennas is below. For center fed, wire dipole antennas, the formula is 468/freq(mhz).

Enter the formula for the antenna:

Your dipole's total length is feet. Each leg of the dipole is feet.

Your Inverted Vee's total length is feet. Each leg of the Inverted Vee is feet.