05-17-2021, 05:47 PM
For reference, my phone is a Beta Edition Convergence PhonePhone (1.2b hardware). I am running Mobian with the following modifications:
Today, I had my first chance to see the PinePhone in action with phone calls in a location with very poor reception. Many places there have no reception. Many other places a phone has to drop to 2G. 4G in a few places, though it is marginal. This was the pattern with my old phone (Nexus 5), and is the pattern with my new PinePhone. At first glance, it looks like my PinePhone is doing a bit better reception wise than my Nexus 5.
Yesterday, I called the landline from a location with good reception and there were no problems. I also did the same earlier tonight at the same location to check, and had no problems.
But in the location today with bad reception, there were major problems that were strongly correlated with the reception.
On my end, there was a loud sound coming from inside the PinePhone case near the earpiece. The sound seemed like PWM whine. So I think it is a switching power supply and a capacitor combination. It quite bad in one location. I moved to another location with better reception and it decreased some. I ended the call and tried again in a location outside with slightly better and the sound was a lot quieter, and I could make it slightly quieter by rotating myself so it would aim in certain directions. My Nexus 5 makes a similar sound but much quieter even in poor reception, and has a similar pattern.
On the other person's end was much worse. They said a very loud sound was coming through on their end which made it even harder to understand me than the sound on my end made it hard to understand them, though my voice was coming through better than on my old Nexus 5 except for the added loud sound. The intensity of the sound decreased as the signal quality improved. From how they described the sound later, it seems like it might have been RF pickup in the microphone line or the sound connection line to the modem. Tomorrow, we are going to attempt to record the sound on their end so I can listen to it and try to figure out more.
Based on the pattern, I think that the sound on my end and the pickup causing loud sound to be transmitted to the other end are due to the increased transmission power as the signal quality decreases. In the worst reception area, the modem is operating at maximum and the problem is at its worst.
For the PWM whine on my end, I am doubtful there is a software solution. Only possibility would be if the PWM frequency is controllable from software. But the PWM whine on my end isn't too terrible (it is tolerable). For the noise transmitted to the other end, it is possible that the settings of the modem, CPU, and sound hardware may have some tangible effect; but I don't know. There is more likely to be a solution, though than for my end.
Hardware wise, assuming I am not the only one with this problem and that the electronics causing it are not inside the modem itself, it might be possible to reduce by finding the particularly switching supply and changing it to a different one as well as changing the capacitor to one that will make less noise (hopefully the capacitor is easy to get to because then it would be possible for the brave to desolder it and solder a new one on). That by itself my reduce the problem to no longer be an issue. The RF pickup can probably also be reduced in other ways.
Anyone have any ideas on this and/or have experienced it?
- Running 5.11 kernel
- Flashed the anx7688 with the latest firmware
- Installed crust-firmware package
Today, I had my first chance to see the PinePhone in action with phone calls in a location with very poor reception. Many places there have no reception. Many other places a phone has to drop to 2G. 4G in a few places, though it is marginal. This was the pattern with my old phone (Nexus 5), and is the pattern with my new PinePhone. At first glance, it looks like my PinePhone is doing a bit better reception wise than my Nexus 5.
Yesterday, I called the landline from a location with good reception and there were no problems. I also did the same earlier tonight at the same location to check, and had no problems.
But in the location today with bad reception, there were major problems that were strongly correlated with the reception.
On my end, there was a loud sound coming from inside the PinePhone case near the earpiece. The sound seemed like PWM whine. So I think it is a switching power supply and a capacitor combination. It quite bad in one location. I moved to another location with better reception and it decreased some. I ended the call and tried again in a location outside with slightly better and the sound was a lot quieter, and I could make it slightly quieter by rotating myself so it would aim in certain directions. My Nexus 5 makes a similar sound but much quieter even in poor reception, and has a similar pattern.
On the other person's end was much worse. They said a very loud sound was coming through on their end which made it even harder to understand me than the sound on my end made it hard to understand them, though my voice was coming through better than on my old Nexus 5 except for the added loud sound. The intensity of the sound decreased as the signal quality improved. From how they described the sound later, it seems like it might have been RF pickup in the microphone line or the sound connection line to the modem. Tomorrow, we are going to attempt to record the sound on their end so I can listen to it and try to figure out more.
Based on the pattern, I think that the sound on my end and the pickup causing loud sound to be transmitted to the other end are due to the increased transmission power as the signal quality decreases. In the worst reception area, the modem is operating at maximum and the problem is at its worst.
For the PWM whine on my end, I am doubtful there is a software solution. Only possibility would be if the PWM frequency is controllable from software. But the PWM whine on my end isn't too terrible (it is tolerable). For the noise transmitted to the other end, it is possible that the settings of the modem, CPU, and sound hardware may have some tangible effect; but I don't know. There is more likely to be a solution, though than for my end.
Hardware wise, assuming I am not the only one with this problem and that the electronics causing it are not inside the modem itself, it might be possible to reduce by finding the particularly switching supply and changing it to a different one as well as changing the capacitor to one that will make less noise (hopefully the capacitor is easy to get to because then it would be possible for the brave to desolder it and solder a new one on). That by itself my reduce the problem to no longer be an issue. The RF pickup can probably also be reduced in other ways.
Anyone have any ideas on this and/or have experienced it?
