Can Bluetooth Go Through Walls?

The first thought that came to mind when I got Britz Bluetooth speaker was to check whether the Bluetooth signal can go through walls.

Guess what I did. I stepped out of the room at the thought of that to connect to the speaker. With two concrete walls between us, my phone was able to connect and even play a song.

With such a small device, it proved to me that Bluetooth signal can go through walls. However, the signal strength is a major concern here.

That is dependent on the Bluetooth range and other factors such as radio frequency interferences. Just as you can hear someone speak in the next room at varying clarity and volume depending on the thickness of the walls, so is the Bluetooth signal strength.

The device’s Bluetooth range is one key thing you have to be concerned about. In my case, I could stand at a distance from the two walls and still be able to connect to the speaker. But how far could that be to still stay connected?

From the horse’s own mouth, Bluetooth devices can range from more than a kilometre down to less than a meter. But developers’ design requirements dictate the range used in devices. Hence knowing the ranges will put you in a comfortable position to go for the right Bluetooth device.

Bluetooth Ranges And Factors That Affect It

The version of your Bluetooth is the first thing to check to know its capability of going through walls.

While several factors may affect its resulting range, the Bluetooth version provides you with the maximum range you can achieve.

As you can see, there are tradeoffs to having Bluetooth of a longer range. The latest Bluetooth version 5.0, however, has been developed to double its speed, improve broadcast messaging capacity and increase the range about 4 times.

While the latest version offers several benefits to the previous versions, you can’t be sure of getting the exact design range. Your Bluetooth overall range will still be determined by factors such as:

Bluetooth Spectrum Band

Bluetooth uses a radio spectrum of frequency ranging from 30Hz to 300 GHz, depending on the device’s design purpose.

The lower the frequency of the radio spectrum, the farther it can go which is the longer its range. However, that comes with a data transfer trade-off.

Spectrum band that provides a good balance of range and data transfer speed is what Bluetooth uses – 2400 to 2483.5 MHz which is available around the globe.

Apparently, all the Bluetooth versions use the same band range, but their Bluetooth range differs. So what makes the difference, then?

Losses in Bluetooth Path

This is also referred to as path attenuation, which is basically the depletion of signal strength over a distance in an environment. In other words, things that come in between Bluetooth devices affect the range of the radio signal.

In an open space, air can cause Bluetooth signal strength to vary, but you can have as high as a hundred meters or even more, depending on the design capacity.

You can’t expect such a high range with denser attenuators like wood, glass, metal, and concrete walls.

However, there are instances where Bluetooth of Low Energy modules have achieved 75 m and 90 m line of sight connection with walls and pillars between the devices.

That’s possible with the adaptive feature hopping implemented on the latest versions of Bluetooth technology.

Antenna Design

How well electrical energy is converted into radio waves from the transmitter to a receiver contributes to the Bluetooth range. It affects how distant Bluetooth devices can be from each other and still communicate.

If the antenna design doesn’t foster signal strength, the Bluetooth range won’t go over a long distance or through walls.

Antenna efficiency has a major impact on Bluetooth range. The reason is that its ability to focus the direction of energy must seamlessly fit with location, packaging size, and design style.

So you don’t have to go in for any antenna. You have to be concerned about its design if you expect stronger Bluetooth signals that could go through walls.

Transmitter Power

While you want a longer Bluetooth range, you also have to bear in mind the power the device consumes. Range and transmitter power go together.

The higher the transmitter power, the farther the signal can travel, even through walls which imply a longer Bluetooth range.

However, this will come at a price of higher power consumption for your Bluetooth device. So if you want stronger signals and have no concern for power, you can consider devices with higher transmitter power.

The sensitivity of the Receiver

Bluetooth signal can be received at the other side of a concrete wall, depending on how sensitive the receiving device is.

Bluetooth devices typically have a minimum receiver sensitivity of -70dBm to -82dBm. This is controlled by the technique used to send data over its radio frequency.

But there are cases where a Bluetooth device can have a sensitivity of -103dBm. Therefore checking out this property is essential if you want your device to detect Bluetooth signals over a wall.

Most of the factors I’ve discussed here are decisions usually made by manufacturers of Bluetooth devices.

What do you do then if the fate of your Bluetooth device is already decided? Let’s see how you can improve the range then.

How To Improve Your Bluetooth Range To Go Through Walls

Upgrade Devices to The Same Bluetooth Version

If your Bluetooth devices have different versions, you can’t expect them to communicate in the same range. They may have different receiver sensitivities.

For example, an older Bluetooth device with the power to transmit over a 33ft range will limit that with a capacity of 1000ft.

You can boost the Bluetooth range of your older device by upgrading it to the latest version. This will be plausible if the hardware supports an upgrade. When you achieve that, you can substantially improve your connectivity.

Bluetooth Signal Repeater

These devices are used as an intermediary between two Bluetooth devices of unequal range.  You use the repeater by placing it between the two devices, keeping it within the range of the shorter or weaker one to provide a signal boost.

For instance, a 33ft Bluetooth range device could use a repeater to broadcast its signal to be able to connect with a 1000ft device. This idea of repeaters seems nebulous in practical use for consumer Bluetooth devices.

However, this solution appears to be in adoption for commercial-grade Bluetooth devices and is expensive.

Bluetooth Signal Extender

Bluetooth signal extender may sound pretty much the same as a Bluetooth signal repeater. But they’re different devices that work in distinct ways to achieve a common purpose-improve Bluetooth range.

You’ll come across them being used sometimes interchangeably, but they’re not the same by way of how they function.

Bluetooth signal repeater connects to your existing Bluetooth device of weaker range and relays it to a wider area.

Bluetooth signal extender also connects to an existing Bluetooth network through a wired link and then broadcasts the signal to another region of space.

Bluetooth extenders can be differentiated into four definite classes in terms of range and power consumption.

• Class 1 Bluetooth Range Extenders: They work within a hundred meters range and consume around a hundred milliwatts of power.
• Class 2 Bluetooth Device Extenders: Ten (10) meters of Bluetooth range and 2.5 milliwatts of power consumption.
• Class 3 Bluetooth Extenders: Less than ten (10) meters range and consume one (1) milliwatt of power.
• Class 4  Devices: It’s the least performing extender considering the range. Has a Bluetooth range and power consumption of 0.5 meters and 0.5 milliwatts, respectively.

Create a Network of Bluetooth Connected Devices

In a research paper titled “An expanded Bluetooth network – a solution to the short-range Bluetooth communication“, the author proposed a network of devices that include laptops, set-top devices, and mobile phones to enable devices to connect with each other within and out of the Bluetooth range.

It shows you the topology of the connection and how you can utilize this proposed network to improve your Bluetooth range.

Final Thoughts

The Bluetooth technology is not a short-range signal, as perceived by many. It’s boldly emphasized to be able to reach a distance of 1km depending on how your device manufacturer specifies its requirement.

This implies that Bluetooth signals can go through walls if designed to their maximum range. However, this is not the case for most customer-use Bluetooth devices.

If you’re handicapped by a number of factors that affect your Bluetooth range, then you can try out the methods shared in this article to improve it.

I hope the article has been helpful to you.