What Is The Range Of Bluetooth And How Can It Be Extended?

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Range of Bluetooth is dependant on its class and primarily there are three classes of Bluetooth:

  1. Class 1 transmitting at 100 mW with a range of 100 meters or 328 feet.
  2. Class 2 transmiting at 2.5 mW with a range of 10 meters or 33 feet (most Bluetooth headsets and headphones are common Class 2 devices).
  3. Class 3 transmitting at 1 mW with a range of fewer than 10 meters.

My lips part into a smile and pleasant nostalgia for the good ol’ days seeps in as I remember exchanging Linkin Park hits on my sliding Sony Ericsson phone. Later, I ‘amplified’ the sound by coercing it to pass through a cone made by my palm, emulating a loudspeaker. Before the introduction of the Internet of Things (IoT) revolutionized wireless communication technologies, Bluetooth technology was the thing.

tv remote control

Image Source: Flickr.com

However, Bluetooth wasn’t our first attempt at manipulating one device with another without wires; infrared had been used as an alternative to data cables for quite some time. Bluetooth merely overcame one major disadvantage, it eliminated the need for line-of-sight positioning. It is due to this limitation that remotes cannot change channels when they are not pointed towards the TV.

Nowadays, Bluetooth seems redundant, but not obsolete. Despite the IoT’s myriad merits and contingencies, Bluetooth has become endangered, but not extinct. It is our generation’s unsung hero, which protects us from awkward conversations and confrontations by powering our wireless headphones, as well as one of mankind’s most important inventions – the PlayStation (or Xbox…to each his own). I have deliberately left out Bluetooth headsets because, well, they look really gaudy and obnoxious.

However, take the joystick a little too far away and the red light abruptly dies. There seems to be a range of distances within which two or a mesh of devices can comfortably converse, but as we will find out, this distance is not fixed and is constrained by several factors.

Bluetooth is not a short-range technology

There is a widely held misconception that Bluetooth, despite not being a line-of-sight technology, can only operate at short distances. This is not true. Also, no… sticking the butts of your phones together would not accelerate the rate of the transfer of information between them, just like how pressing harder on the joystick buttons does not make your car go faster. Bluetooth or radio waves behave like any other wave, such as sound waves.

The distance that the wave travels relies on both how loud one shouts, the obstacles it must flow around and the sensitivity of the listener. Thus, the louder you shout, the farther your voice will travel, which partly comes down to hardware — the structure of your voice box, lung capacity and so on. This implies that Bluetooth is power-dependent or, in terms of Bluetooth technology, it is class dependent.

Bluetooth devices transmeter classes

There are three classes that offer three standard intended ranges. Class 1 devices transmit at 100 mW with a range of 100 meters or 328 feet. Class 2 devices transmit at 2.5 mW with a range of 10 meters or 33 feet. Most Bluetooth headsets and headphones are common Class 2 devices. Lastly, Class 3 devices transmit at 1 mW with a range of fewer than 10 meters. Notice that these are intended ranges, which is where the other part comes into play. Ranges can be drastically reduced by obstacles between the two devices, such as walls that attenuate signals. Thus, the range is influenced by transmitter strength, receiver sensitivity, and obstructions in the device’s proximity.

Can we extend them any further?

Spatial constraints hinder communication when the devices are part of a larger, distantly distributed network. Newer versions of Bluetooth boast ranges from around 250 feet to 800 feet, so updating your device seems to be the most lucrative solution. However, ranges can also be stretched by recruiting signal repeaters. These are intermediate devices that capture the signals, amplify them and then re-transmit or repeat them without any distortions. For instance, a 33-foot range device connected to a 1,000-foot repeater allows the device to enjoy a 1,000-foot range.

Bluetooth repeater

(Photo Credit: Optimus Energy)

You could also take the matter into your own hands. There are several DIY methods you will find on YouTube to extend Bluetooth ranges by tinkering with Bluetooth modules inside your device. So, grab a soldering rod, a  few screwdrivers and rouse your inner engineer. Another cost-effective method is to align your devices such that their signals cannot be interrupted by obstacles.

Bluetooth proved to be of great service for a decade, throughout which it made tremendous progress. However, it plummeted to the level of nearly defunct due to a major shortcoming — security. When it comes to security, Bluetooth has been a major letdown. Attacks like BlueSnarfing, which ambushed Nokia and Ericsson phones, allowed attackers to connect and manipulate devices without authentication. Even so, its contributions will be cherished by introverts and night owls for posterity.

References

  1. SANS Technology Institute
  2. Missouri University of Science and Technology
  3. Wikipedia
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About the Author:

Akash Peshin is an Electronic Engineer from the University of Mumbai, India and a science writer at ScienceABC. Enamored with science ever since discovering a picture book about Saturn at the age of 7, he believes that what fundamentally fuels this passion is his curiosity and appetite for wonder.

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