2 of 2 people found this helpful
4 dBm of Tx power is the max we can go within the class 2 requirement. In actual deployment, I wouldn't go beyond 10m for reliable connection, considering antenna efficiency as well as orientation.
BT has something known as RSSI. Essentially, if two devices are near to each other, they will reduce their required Tx power to talk to each other. And vice versa.
What is the range you are looking for? Bearing in mind that BT/BLE are PAN devices which are never intended for "long" range use. If you really want range, then you might want to consider using BT instead of BLE. The former can be configured as a Class 1 (up to 20dBm of Tx power) and will definitely have a much better range.
Thank you in advance for your reply.
I want "20737S" to have reliable paring performance within 10 meters.
Our requirement is that It should be able to have reliable connection between mobile application and our device.
But the our product device is wrapping aluminum cover or some kind of stainless steel case.
That is just the problem. RSSI value is getting quite weak because of the enclosure case.
I test the pairing distance within 10 meters with that case opened. Nevertheless, I can not
scan the device on the mobile application occasionally. The pairing distance varies with commercially
available mobile phone or some BLE scanner apps.
I don't know what factors affect the reliable connection and the paring distance.
That is why I asked the question on the previous post. I just want reliable paring and stable connection within
3 of 3 people found this helpful
The metallic shielding could potentially have some negating effect on the RF radiation. I advise you seek out your HW engineers to come out with an optimum placement of the 20737S within your product.
You may want to use "LightBlue", an app available on iOS, to discover the module and take note of the received signal strength at say 5m, 8m and 10m. If you see something below -90dB, then you are nearing the limit already. In my opinion, I think -80dB is probably the weakest signal if you want to maintain some reliability...