To extend the battery life of modern portable devices, Bluetooth uses a low-power 2.4Ghz signal. As a result, it can be fairly easy to block or interfere with a Bluetooth connection. Connectivity issues can cause a wide range of issues in a Bluetooth connection, including:
• Poor range
• Failure to locate a new device for pairing
• Failure to pair or connect to a device
• Gaps in audio on Bluetooth headsets and speakers
• Dropped connections
• High latency in audio
• Failed file transfers
• Jumpy or intermittent cursor movement in Bluetooth mice
• Missed keystrokes in Bluetooth keyboards
Interference
Bluetooth connections can be disrupted by interference from any other device that emits a 2.4Ghz signal. Common sources of 2.4Ghz interference include 2.4Ghz Wi-Fi routers, other Bluetooth devices, cordless home phones, baby monitors, wireless security cameras, and microwave ovens (while cooking).
To locate the source of connectivity issues, it can help to temporarily power off and unplug devices like these. For example, if the issue clears up when a router is powered off, the router is likely interfering with your Bluetooth connection.
Once the source has been found, steps can be taken to mitigate the interference. Updating an older 2.4Ghz router to a 5Ghz model is one option. Many modern routers support both 2.4Ghz and 5Ghz, in which case the 2.4Ghz radio can generally be turned off in the settings page of the router, allowing your Wi-Fi devices to continue connecting at 5Ghz. Cordless phones, baby monitors, and security cameras are also available in 5Ghz models.
In many cases, interference can be reduced just by moving the source of the interference farther away from the affected Bluetooth device.
Obstructions
Bluetooth can also be blocked easily by physical obstructions. Metal objects, or dense objects like solid wood or the human body, are particularly good at blocking Bluetooth.
Obstructions can be a bigger problem when Bluetooth devices are used outdoors. While indoors, Bluetooth signals can often reflect off of nearby flat surfaces, like walls and ceilings, to travel from one device to another. When Bluetooth is used outdoors there are often no nearby flat surfaces to reflect the signal, allowing obstructions to cast shadows in the signal.
For example, Bluetooth headsets often have their receiving antenna in the right earpiece. If your phone is on the left side of your body, your body will cast a signal shadow over the antenna in the headset. Improving connectivity in this case may be as simple as moving your phone to a pocket on the right side of your body.
Indoors, poor connectivity is often the result of severe obstructions. For example, desktop computers are often kept underneath wooden or metal desks. A Bluetooth USB adapter plugged into the back of such a computer is likely to be almost completely enclosed on all sides, leaving little opportunity for the signal to propagate to the rest of the room. Plugging the USB adapter into the front of the computer, moving it a USB port on a monitor or hub, or moving the computer itself to a more open location are all good ways to improve connectivity.