What is a Yagi Antenna?

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Yagi antennas are also called directional antennas. These are powerful RF signal receiving and transmission antennas for home, office, and RV.

In our earlier post, we shared a guide to choosing the best outdoor antenna for your cell signal. In this post, we’re going to take a deeper dive into Yagi antennas; what they are, what they do, and when we suggest using them.

What are Yagi antennas and what do they do?

A Yagi antenna is also called a directional antenna. When talking about cell phone signal booster antennas, Yagi antennas are outdoor antennas that are created to focus their reception and transmission window in one direction, which has a 50-degree field of coverage. This limited window gives a big boost to the antenna’s strength and ability to access radio frequency (RF) signals and cell towers that are further from your building.

The internal components of the antenna include a conductor and insulated dipoles that run parallel to the conductor. These simple components work together to create a high-gain antenna, which means it produces around -9 to -11 decibel (dB) of gain to give mobile users a performance boost.

Who would need a Yagi antenna?

Owners of homes, offices, multi-unit buildings, RVs, warehouses, and other spaces with RF signal readings between -91 and -135 dB outside of the building are likely receiving very little to absolutely no cell reception. That weak to nonexistent reception could be caused by a few different factors including building materials, mountains, trees, cell tower capacity, and cell tower location (get the details about what’s blocking your cell phone signal).

Regardless of the cause for the weak cell phone signal, an RF reading between -91 dB and -105 dB may benefit from a Yagi antenna. It is important to note that we consider an RF reading between -106 dB and -135 dB to be a nonexistent signal and this can be very difficult to improve regardless of antenna, booster, or manufacturer.

Keep in mind, however, the additional considerations below, as each installation is unique:

1. One or Multiple Carriers

The nature of cell phone towers is that most of the time AT&T will want to own their own tower, rather than sharing a tower with the other major carriers. In more rural areas, however, carriers will often cut the cost by sharing a tower. So how does this relate to Yagi antennas? Well, being that Yagi antennas are directional, they will most likely only be able to point at one tower. This means that if that tower is owned exclusively by AT&T, you will only be able to amplify the AT&T signal, unless the towers of other major cellular carriers are within the Yagi’s 50-degree window of reception. However, if the tower you point your Yagi at supports all major carriers you would be able to pull in the signal from each and every one of them.

2. Space from Other Antennas

If you already have antennas on your roof for satellite cable or any other antennas, you will want to keep in mind that a Yagi antenna can be placed as close as you would need to other antennas, so long as neither antenna is pointed at the other. If one Yagi antenna is in the reception window of another antenna, this will create interference and can have a weakening effect on your booster’s performance.

3. Space Between Indoor & Outdoor Antennas

Best practice is to have 30-feet or more of separation between your indoor antennas and outdoor antennas. Much like the previous consideration, this reduces interference to ensure you get the best performance possible from your booster. While the booster will still perform if the antennas are closer to one another, it will be at a lesser level.

In Summary

Yagi antennas are powerful and efficient transmitters and receivers of RF signals that perform well for homes, offices, multi-unit buildings, RVs, warehouses, and other spaces that have a weak RF signal readings. Unfortunately, if the signal reading outside of your building is critically poor, it will be questionable as to whether a signal booster will be able to resolve your poor signal. Before buying, you should consider whether you want to boost one carrier or many as well as how much space you have between any other antennas inside or outside of the building.

If this sounds like you, view our antenna options here. If this doesn’t sound like the best option for you, learn more about the alternative, an omni-directional antenna, in our Which Outdoor Antenna is Best for my Cell Signal blog post.

Have another question? Contact an install expert.

2 Comments Add yours

  1. Fransisco L. says:

    It is misleading to suggest that with a yagi antenna, your amplifier would be able to perform in a -135dB environment. From my experience, if the outside isgnal is not great er than -95dB, you don’t have much of a chance of getting a useable, amplified signal.

    1. Thomas Warren says:

      That’s a great point Francisco and we completely agree. -95 or better is better, by far, and while we do have a few -100 and worse signals that a Yagi has resolved, it does tend to be very rare.

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