Bluetooth distance performance test method？

[Mikey]

Hi nordic,
In the products I developed, since the entire product is metallic, only a small part is a non-metallic material, and an antenna has been designed to solve the problem of conflict space.But I have no effective and reliable way to test the Bluetooth distance and reach our product specifications. We tested the test method of the test at this stage to handle the machine or fix the machine, and another person took a mobile phone to go far away, and recorded the connection distance of Bluetooth, from development until now, it has been used.Affected by other factors, I don't think that testers can provide an effective test report. So I would like to ask if the RSSI is at the distance interval every 10 meters, is the RSSI's data beat range as the reference point? Or Nordic has a better test method for providing better testing our Bluetooth products? Can you provide me?

Related information: Chip NRF52833, SDK17.1, Bluetooth protocol stack S140, Bluetooth transmit power: 8dB, and use Automatic Phy Selection.

Thanks.

[ketiljo]

RSSI is not a good way to test range. It's better to check the connection to a phone, either with your FW or for instance the HRM example https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/ble_sdk_app_hrs.html

Make sure you are in an open field to get comparable results. Testing range indoors will give unpredictable results as the reflections will change when you move or other people move near by. 

[Mikey]

My product needs a distance of more than 50 meters, so what instrument do I need to detect whether the distance performance of my product meets the standard. Manual measurement will interfere, so I want to consult whether there is a good method. Hrs this project doesn't seem to help me much.

[ketiljo]

It depends only on your application. You need to find a reliable and repeatable way to test range. You could measure the field strength of the antenna and estimate range that way, but that requires access to an anechoic chamber and a reference antenna at least. Better to setup an open field measurement and test with the FW you're using.