RDPUser
Posts: 148
Joined: Tue Jan 30, 2018 12:18 pm

Raspberry PI4 very short Bluetooth range, increasing trasmit power?

Mon Dec 30, 2019 1:56 am

I have a PI 4 and a PI Zero W. Sending Bluetooth packets with the PI 4 I've noticed quite a short range. So I've made a test between a RPI 4 and a Zero W. Each sending bluetooth Pakets and measuring the received signal strength. I know the signal strength may be calculated differently on both devices so it is not 100% exact, but considering that I notice the strong increased range of the Zero W compared to the PI4 with my Smartphone these received signal strength values are a good indicator.

Of course during this test both devices haven't been moved.

Values:
Transmitting from PI4 to PI Zero W (signal strength on the PI Zero W): -94 dBm to -88dBm
Transmitting from PI Zero W to PI4 (signal strength on the PI4): -85 dBm to -75dBm
Thats about 10dB difference, so a 10 times stronger signal.

Is there any option to increase the transmit power?

BTW: Here is an issue with a very short wifi range of the PI4 https://www.raspberrypi.org/forums/view ... 8&t=260581
OK thats a really short range, but since both are 2,4 GHz perhaps they are correlated somehow.

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