# Does a 1/4 wave antenna need a ground plane?

## Does a 1/4 wave antenna need a ground plane?

Does a 1/4 wave antenna need a ground plane? Answer: Yes. All 1/4 wave antennas work best if they are installed in the center of a metal ground plane with at least 1/4 wave length radius (1/2 wave length diameter: ~6 inches for 900Mhz and ~3 inches for 2.4Ghz); larger is better.

## How do you calculate 1 4 wave antenna?

1/4 wave length antenna take 300 and divide by the frequency. So 150 MHz becomes 2 meters, 300 MHz becomes 1 meter, 600 MHz becomes 1/2 meter. Then take the length in meters and multiply by 3.28 to convert to feet (unless you want to remain metric). Take that result and divide by 4 for 1/4 wavelength.

How much gain does a 1/4 wave vertical antenna have?

So on a scale of dBd (gain referenced to a dipole) a 1/4 wave vertical has about -3 dBd (that is negative 3 dBd, less than one). On a scale of dBi (gain referenced to an isotropic) it is about -0.85 dBi.

What is a 1/4 wave?

The size of a 1/4-wave antenna is approximately one-quarter of the wavelength of the desired frequency, and the 1/2-wave is one-half the wavelength. For VHF applications, an antenna anywhere from 14-18 inches (35-45 cm) is perfectly appropriate as a 1/4-wave antenna.

### What is the difference between 1/4 wave and 5/8 wave antenna?

5/8th wave gain is now 1.95 dB over a 1/4 wave antenna at 2 degrees, but the peak gain is only . In the real world the actual gain difference between a 1/4 wave antenna and a 5/8th wave can be anywhere from no gain or a very slight loss up to a maximum of 2dB gain over a 1/4 wave.

### What is the approximate length for a 1/4 wave vertical antenna cut for 28.5 MHz?

8 feet
What is the approximate length for a 1/4-wave vertical antenna cut for 28.5 MHz? The approximate length of wire to cut for a 1/4 wavelength vertical antenna for 28.5 MHz is 8 feet.

Is a half wave antenna better than a quarter wave?

A half-wave antenna is a good choice when your entire device is much smaller than a quarter-wavelength, or when you are building an antenna that is physically separated from the transmitter.

Does a 1/4 wave antenna have gain?

A 1/4 wave antenna exibits about 1.2 dbi gain, while a halfwave exibits 2.14 dbi, or an increase of . 94 db.

## What is the difference between 1/2 wave and 5/8 wave antenna?

The 1/2 wave antenna is usable where you do not have a ground plane. For instance, if you car has a fiberglass body. The 5/8 wave antenna has the most gain and would probably be your better choice. (I just use a 1/4 wave whip.)

## How to calculate 1 / 4 wave ground plane antenna?

1/4 Wave Ground Plane Antenna Calculator Give me the results in… mm (MilliMetres) cm (Centimetres) m (Met A. Vertical Monopole Radiating Element ( B. Radials (λ*0.28)*vf Actual wavelength

How many radials are needed for a quarter wave antenna?

This calculator can be used to design a Quarter Wave Ground Plane antenna, with radials. The radiating element is a quarter wave (λ/4) and the radials are 12% longer. There are usually four radials, three being a minimum, but you could use up to six.

Which is the best antenna for 6 meters?

The 1/4 wave vertical is one of the most forgiving antennas there is and has very good performance for its size and wind loading. Vertical polarization is used exclusively on 6 meters in the FM portions of the band.

### How big is a 70cm ground plane antenna?

The next two images show one I built for the 70cm band. It is good for use between 430-440MHz. It uses 6mm aluminium tube for the radials, 4mm brass tube for the driven element and is built around an N-Type chassis socket mounted to a 40x40mm aluminium square, held together with rivets.