08-14-2021, 10:20 AM
(07-28-2021, 10:27 AM)dsimic Wrote: A few days ago, one community member complained on the #pinephone IRC channel about having some kind of weird interference on his PinePhone, during a 2G voice call. After some debugging, which included changing the audio-related modem settings through some of the above-listed AT commands (with no success), we came to a conclusion that we need a weird approach: let's make the modem antenna larger.
With that mod in place, signal strength (as reported by the "AT+CSQ" command) went up from around -100 dBm, which is considered poor, to around -70 dBm, which is considered very good, and no interference was present during a voice call. Thus, I'd suggest that you try something similar, just to verify whether the issues are caused by the network and low signal strength. Of course, improving the modem antenna is nowhere nearly as easy as sticking a randomly shaped piece of aluminum foil to the back cover, but that's all just for the purpose of testing.
The attached picture shows what the "early prototype" looked like.
Not surprised that the AT commands didn't work since sound stuff on the modem end is way after the microphone. Though AT commands affecting the power systems in the modem might have an effect.
That antenna modification is clever. Makes sense that it helped. Modem is less likely to drop to 2G and crank up the transmit power in a burst fashion.
I am going to try that.
(07-29-2021, 05:24 AM)mouffa Wrote: I thought down there was the Wifi/BT antenna and the 3 antennae on the top were for the modem.
I've tried to look for diagrams of which antenna is which and have not found any. So I don't know. In fact, I don't even know if the whole thing at the bottom is one antenna or two (no information on whether the left most antenna piece is connected electrically to the others).
Anyhow. If the modification was on the right antenna, that is a nice simple work around. If it is the wrong antenna, while it is still a nice work around, the fact it works would imply that there is some interference going on between the different antennas which is a larger problem (adding metal to the wrong antenna
