## Antenna Calculator

### Ground Planes

The standard ground plane antenna consists of a vertical radiator which
is insulated and centred 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 half wave 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 feed line if you wish to use coax.

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

Switch to:

divided by
Freq. MHZ

Your half wave 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 :

• The antenna
height above the ground

• The diameter of the wire
used

• Nearby structures
to where the antenna is mounted

• Effects of other antennas
or metal objects in the area

• The conductivity of the soil

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

divided by
Freq. MHZ

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, half wave
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:

divided by
Freq. MHZ

Percent smaller for an Inverted Vee.

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.