Has anyone else tried using different gain settings for daytime and nighttime?
I've been trying this for the last couple of weeks with good results.
A bit of background first:
Raspberry Pi, RTL-SDR dongle, LNA, homemade coax collinear antenna, all in a loft.
House is between Heathrow and Luton, under fairly busy airspace.
I had noticed that overnight my signal level and noise levels were well below what they were in the day. I had set gain so that the max level was around -3dBFS, so the setup was about as as good as a newbie like me could do. I realised that the high levels were caused by aircraft in stacks or approach/departure, and that as noise considerations meant this didn't happen overnight, I might be able to increase my sensitivity during that time.
Looking at the signal level plots, I reckoned a good time for switching was 2330 and 0530. I made copies of the dump1090-mutability config file with different gain settings, and created cron jobs to copy them into /etc/default then restart dump1090-mutability.
Timings and gain settings will obviously vary by location, but I can increase the gain by around 10 dB overnight. This brings max signal level and noise back to what they are in the day. Message rate and coverage/max range are now better at night than in the day. YMMV!
I noticed that the stats do odd things at the switchover (e.g. the message rate spikes). I assume this is related to some buffering during the restart. I've got a small concern about how the restart might manipulate the stats, but haven't noticed anything else yet.
Would love to hear people's thoughts and experiences of this.
I've been trying this for the last couple of weeks with good results.
A bit of background first:
Raspberry Pi, RTL-SDR dongle, LNA, homemade coax collinear antenna, all in a loft.
House is between Heathrow and Luton, under fairly busy airspace.
I had noticed that overnight my signal level and noise levels were well below what they were in the day. I had set gain so that the max level was around -3dBFS, so the setup was about as as good as a newbie like me could do. I realised that the high levels were caused by aircraft in stacks or approach/departure, and that as noise considerations meant this didn't happen overnight, I might be able to increase my sensitivity during that time.
Looking at the signal level plots, I reckoned a good time for switching was 2330 and 0530. I made copies of the dump1090-mutability config file with different gain settings, and created cron jobs to copy them into /etc/default then restart dump1090-mutability.
Timings and gain settings will obviously vary by location, but I can increase the gain by around 10 dB overnight. This brings max signal level and noise back to what they are in the day. Message rate and coverage/max range are now better at night than in the day. YMMV!
I noticed that the stats do odd things at the switchover (e.g. the message rate spikes). I assume this is related to some buffering during the restart. I've got a small concern about how the restart might manipulate the stats, but haven't noticed anything else yet.
Would love to hear people's thoughts and experiences of this.
Comment