Directional Antennas: All You Need to Know

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A directional antenna is a unique antenna that only favors a particular direction. In other words, this antenna focuses the signal into a beam that is sent to one certain direction at the expense of others. To know more about directional antennas, keep reading!

How does a directional antenna operate?

For a directional antenna to operate, a high-gain antenna is used on the transmitting end. This allows sending signals with higher transmission power to be sent in the direction of the receiver.

Similarly, on the receiving end, a high-gain antenna is installed to capture the signals of high strength. This reciprocity makes these signals equally powerful and about 100 times stronger than isotropic antennas.

This particular setup of the directional antennas allows them to receive and send lesser signals to other directions. You can thus use these antennas when you wish to reduce or eliminate interferences as much as possible.

Parabolic antennas, Yagi antennas, helical antennas, etc., are some of the common antennas that are used to make high-gain receivers/transmitters.

What is the radiation pattern of a directional antenna?

Directional antennas are designed to produce signals in a focused beam similar to a flashlight. The horizontal beam-width of this antenna ranges from 40 to 80 degrees, depending on the type of antenna.

You can imagine the shape of the beam to appear like that of a flashlight beam. It is stronger at the center and begins to fade as we move away from the center. A signal sent from a directional antenna works in a similar fashion.

Thus, at VHF or UHF, these can work ideally when you require maximum distance coverage and minimum interference.

When can you consider using directional antennas?

You must use a directional antenna in the following cases only:

  • When the line of sight is totally clear. If there are any obstacles between your ham radio’s antenna and the tower, the signal received might get distorted.
  • When all the given cell towers are located in the same direction as you.
  • When you have to communicate from a distance that is far off the range of an omnidirectional antenna.

What are the types of directional antennas available?

You can find a directional antenna in a variety of designs, shapes, and sizes. Its structure basically depends on the intended purpose of use and the needed extent of the signal power.

Some of the commonly used antennas are Panel antennas, Grid Antennas, Parabolic antennas, Yagi antennas, and Sector Antennas. These are mostly used for satellite, Wi-fi networking, or over-the-air ham radio broadcasting purposes.

Summing up

A Directional antenna can be a great choice when you are considering to boost the signal range and clarity. The concentrated signals of a directional antenna can enhance the entire broadcasting system with powerful signal transmission/reception.

The gain and range of a directional antenna are also much better as compared to an omnidirectional antenna. With lower chances of interference, this antenna also has better quality and improved propagation.

Lastly, according to the purpose of the directional antenna, and the needed range and strength, it’s structure might vary. So, you can take into consideration all these characteristics when you choose a ham radio for yourself.