Most people imagine Bluetooth beacons transmit equally in all directions. However, this isn’t usually true. The 2.4 GHz frequency that beacons use is easily blocked or affected (through electronic resonance) by items such as the casing, the battery and even the printed circuit board itself. Also, the design of the antenna, that’s usually etched onto the printed circuit board, causes the transmission to vary depending on the direction.
Printed Circuit Board (PCB) Antenna
The above 2D design leads to different radiation depending on whether you are viewing face on, sideways or end on. The following diagram from a very informative Cypress article (pdf) demonstrates how the radiation pattern can vary in the x y and z planes:
In practice, it’s best to perform tests to assess how the beacon radiation changes with beacon orientation. You can do this by measuring the change in RSSI as you orientate the beacon. You can measure the RSSI using an app such as nRF Connect.
For example, with the long 300m range iB003N-PA, we determined experimentally that the best range was when the non-battery face of the beacon was facing the observer.
iB003N-PA – Strongest signal for us was downwards in this photo
However, this was for our particular scenario. How and where the beacon is mounted can also affect transmission and hence range.
So, the next time you are testing the range or installing beacons, take some time to assess how the beacon orientation might be affecting the range.
Beacons are often placed in shops, offices and other buildings for detection in smartphone apps. Battery powered beacons last from months to years depending on the size of the battery and the transmission power (adjustable). The compromise between battery life and physical range can be avoided if USB beacons are used instead.
USB beacons are powered from an available wallsocket, laptop, desktop or other standard USB socket. Alternatively, they can be powered using an inexpensive mains charger used to charge a smartphone or other device. Powering from the mains allows the beacon to be permanently set to full power with no worry about checking or changing the battery.
The use of mains power also allows for use of specialist beacons that output the maximium legally allowed (Class 1) power that wouldn’t be feasible using battery power.
The FSC-BP109 can be received up to 1000m on Android and 4000m on iOS.
It’s an electronic component to be used at the SoC output to amplify the signal prior to being sent to the antenna. We expect this to be included in some future long range beacon designs. However, note that it uses more current (115 mA at +20 dBm) so is less suitable for use in coin-cell based battery powered designs.
Our ultra long range beacons already use RF amplifiers but from different component manufacturers. For example the iB003N-PA uses a RFAXIS X2401C chip to achieve up to 300m range. The FSC-BP109 also uses an output amplifier to reach up to 1000m on Android and 4000m on iOS but this beacon requires USB power.
If you have been following our posts on Bluetooth 5, you might be wondering how one Bluetooth device can communicate to many devices, some of which might be legancy Bluetooth 4.
There’s a new video from Nordic Semiconductor (who produce the System on a Chip – SoC – inside most beacons) where the new long range mode is used while connecting to up to 20 devices. These can be different PHYs meaning that different capabilities, for example high speed vs long range vs legacy) can be connected at the same time.
We just received the 210L ultra-long 200m range beacon into stock.
Most beacons tend to have a range of 30m, 50m or 100m. The normal output is 0dBm but they can be boosted to +4dBm to achieve the maximum ranges. Read our article on Choosing the Transmitted Power for more information.
The 210L beacon transmits at +10dBM which is the maximum allowable for this class of Bluetooth 4 device. This is just over 3x the power of a beacon transmitting at 0dBm. Hence, there’s respective reduction in battery life.
This Bluetooth Class 1, CE RED certified beacon transmits, iBeacon and Eddystone, between 1000m and 4000m depending on the receiving device.
There are new iOS and Android apps that allow up to 10 channels that can transmit anything: Eddystone-UID, Eddystone-URL, iBeacon or AltBeacon. You can still set up by sending AT commands through the laptop/desktop USB com port opening up the possibility of the advertising changing programmatically over time, for scenarios such as changing media displays.
This beacon is especially suitable for large open areas such as stadiums where it can replace 10s or 100s of beacons with shorter range.