Antenna

An antenna is a device that picks up and transmits radio waves. There are many different types of antennas, all with their advantages and disadvantages.

Dipole antenna

The dipole antenna is a very simple and common type of antenna. The dipole antenna has two, often identical, conductive elements. The antenna has a total length of 1/2 wavelength.

Vertical antenna

The vertical antenna is a very simple antenna consisting of a vertical rod.

Cubical quad antenna

The cubical quad antenna consists of multiple squares placed one after another. The first square is the reflector, the second one is the driven element and all other squares are directors.

Inverted vee antenna

The inverted vee antenna looks like an upside down V, often at a 120 or 90 degree angle. The antenna has a rod in the center to support the V shape. The inverted vee antenna takes up less space than a standard dipole antenna operating at the same frequency, so it can be a good alternative when less space is available.

Ground plane antenna

The ground plane antenna consists of a vertical rod lifted by four radials. The ground plane antenna is designed for unbalanced feed cables, like a coaxial cable. The driven element is often 1/4 λ long and the frequency is often between 10 and 512 MHz.

J-pole antenna

The J-pole antenna consists of a short and a long vertical pole with a feed point near the bottom. The antenna looks like the letter J, hence the name J-pole antenna.

Small magnetic loop antenna

The magnetic loop antenna consists of two circles: one large one and a smaller one in the larger one. The circumference should be between 0.1 and 0.25 wavelength for optimal efficiency.

Full-wave loop antenna

The full-wave loop antenna consists of a loop elevated from the ground. A circular loop is the most efficient, but squares are also very common because square loops are easier to set up. The full-wave loop antenna has a higher gain than the dipole antenna, but takes up less space when operating at the same frequency.

Three element yagi antenna

The yagi antenna is a directional antenna with multiple elements placed one after another. The Yagi-Uda antenna has one driven element, one reflector one side and one or more directors on the other side.

Seven element yagi antenna

The yagi antenna is a directional antenna with multiple elements placed one after another. The Yagi-Uda antenna has one driven element, one reflector one side and one or more directors on the other side.