Why is a specific gain chosen from autogain?

Question

Why is a specific gain chosen from autogain?

Drudoo opened this issue 3 years ago · 6 comments

I've been running the autogain sequence and i am now in the final state. My next review is scheduled for may 2022.
But i feel like the chosen gain is wrong.

File	Value
autogain_current_value	32.8
autogain_max_value	49.6
autogain_min_value	29.7

I'll try and list some of the findings and explain why i feel like the chosen value of 32.8 is wrong.
All these numbers are from the .finetune files, not the .init files.

gain	autogain_results	pct_strong_msgs	max_distance	total_accepted_msgs	tracks_new
29.7	-37	3.250	422732	5310215	5348
32.8	1650	3.880	441913	7019561	7917
33.8	1551	3.590	519896	7000562	8238
36.4	1212	3.270	454991	7050111	8062
37.2	764	3.040	462524	7031887	8283
38.6	256	3.180	439159	7231599	9218
40.2	17	2.700	437740	7076983	7843
42.1	949	2.510	448339	7184047	8917
43.4	36	1.030	443968	7116347	5586
43.9	38	.5800	442202	7128397	8149
44.5	60	.7100	434903	7084865	7979
48.0	39	.6700	446719	7020796	8306
49.6	71	.2300	465604	27826003	29576

Looking at this, i feel like 33.8 should be the accepted gain, but i would actually prefer a much higher gain like 48.0 or 49.6. I live right next to a major airport (like 3km to tarmac, 5km to the gates) and i pickup so many signals from ground vehicles and parked planes. I am thinking those signals are kinda skewing the results of the autogain, as my current gain (32.8) gives me way less airborne planes and less long distance planes compared to when i was using a gain above 45.

Sure it is nice to track the planes from the gates, to the runway and departing, but i lose most planes at the 50km mark.

Looking at my feeder right now, i am getting a message rate of 250msg/s with 24/15 aircraft. But 5 are grounded and parked (not at gates, but like in storage/maintenance buildings) and 2 are non aircraft vehicles, which services the runway. 3 of those 15 aircrafts are outside of my 50km radius, whereas the rest are within 50km (most within 25km).

Should i just ignore the autogain and do some trial and error in order to find a satisfying gain or is there a way to filter the results by altitude, so i avoid those parked aircraft and vehicles?

Answer 1 · 2021-05-27T10:22:25.000Z

From the table above I’d have to agree with you that 33.8 would seem to be the best.

I’d like to have a look at all of the files in your autogain folder. Are you able to join our discord so I can grab them from you?

Answer 2 · 2021-05-27T10:30:11.000Z

Sure thing. I'll PM you on the discord.

Answer 3 · 2022-04-12T19:18:08.000Z

Hi,
I think there's something strange on autogain logic... I set a reasonable gain value, got too few messages for a day, then the script didn't test any other gain value. Here's my log:

readsb          | [readsb] 2022/04/11 13:04:32 Found Rafael Micro R820T tuner
readsb          | [lighttpd] 2022/04/11 13:04:32 2022-04-11 13:04:32: server.c.1513) server started (lighttpd/1.4.59)
readsb          | [readsb] 2022/04/11 13:04:32 rtlsdr: tuner gain set to 49.6 dB
readsb          | [readsb] 2022/04/11 13:04:32 Mon Apr 11 13:04:32 2022 CEST  Waiting for receive thread termination
readsb          | [readsb] 2022/04/11 13:04:32 Mon Apr 11 13:04:32 2022 CEST  Normal exit.
readsb          | [readsb] 2022/04/11 13:04:33 Mon Apr 11 13:04:33 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [readsb] 2022/04/11 13:04:33 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/11 13:04:33 Found Rafael Micro R820T tuner
readsb          | [readsb] 2022/04/11 13:04:33 rtlsdr: tuner gain set to 25.4 dB
readsb          | [readsb-db-update] 2022/04/11 13:04:37 readsb webapp database updated from version 294 to version 296
readsb          | [graphs] 2022/04/11 13:05:32 Initialising graphs
readsb          | [autogain] 2022/04/11 15:04:34 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 16:04:35 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 17:04:37 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 18:04:38 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 19:04:39 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 20:04:40 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 21:04:41 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 22:04:42 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/11 23:04:44 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 00:04:45 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 01:04:46 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 02:04:47 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 03:04:48 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 04:04:49 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 05:04:50 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 06:04:51 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 07:04:53 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 08:04:54 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 09:04:55 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 10:04:56 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 11:04:57 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 12:04:58 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 13:04:59 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 15:05:02 Insufficient messages received for accurate measurement, extending runtime of gain 25.4 dB.
readsb          | [autogain] 2022/04/12 17:05:06 Auto-gain stage 'init' complete. Best gain figure appears to be: 25.4 dB.
readsb          | [autogain] 2022/04/12 17:05:06 Entering auto-gain stage: finetune

Answer 4 · 2022-04-13T03:42:46.000Z

@ebaschiera can you please post the readsb: section of your docker-compose.yml file? Please redact any sensitive information. Thanks.

Answer 5 · 2022-04-13T06:35:40.000Z

Sure @mikenye

  readsb:
    image: ghcr.io/sdr-enthusiasts/docker-readsb-protobuf:latest
    tty: true
    container_name: readsb
    hostname: readsb
    restart: unless-stopped
    devices:
      - /dev/bus/usb/001/003:/dev/bus/usb/001/003
    ports:
      - 8083:8080
      - 30005:30005
    networks:
      - adsbnet
    environment:
      - TZ=Europe/Rome
      - READSB_DCFILTER=true
      - READSB_DEVICE_TYPE=rtlsdr
      - READSB_FIX=true
      - READSB_GAIN=autogain
      - READSB_LAT=<x>
      - READSB_LON=<y>
      - READSB_MODEAC=true
      - READSB_RX_LOCATION_ACCURACY=2
      - READSB_STATS_RANGE=true
      - READSB_NET_ENABLE=true
      - AUTOGAIN_MAX_GAIN_VALUE=25.4
    volumes:
      - readsbpb_rrd:/run/collectd
      - ./readsbpb_autogain:/run/autogain
    tmpfs:
      - /run/readsb:size=64M
      - /var/log:size=32M

In the meantime I switched to a lower gain value (15.7) and it's giving better results. Still reporting Insufficient messages received for accurate measurement, extending runtime of gain 15.7 dB, tho.
Thanks!

Answer 6 · 2022-04-19T21:39:20.000Z

Hi,
I did one more test with a different max gain: 20.7 dB. The script reduced gain value down to 16.6 dB, said that it was good, but then switched back to 20.7.
Here's the log:

readsb          | [autogain] 2022/04/15 23:02:03 Entering auto-gain stage: init
readsb          | [collectd] 2022/04/15 23:02:03 [2022-04-15 23:02:03] plugin_load: plugin "logfile" successfully loaded.
readsb          | [readsb] 2022/04/15 23:02:03 Fri Apr 15 23:02:03 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [services.d] done.
readsb          | [readsb] 2022/04/15 23:02:03 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/15 23:02:03 Fri Apr 15 23:02:03 2022 CEST  Caught SIGTERM, shutting down..
readsb          | [readsb] 2022/04/15 23:02:03 Found Rafael Micro R820T tuner
readsb          | [lighttpd] 2022/04/15 23:02:03 2022-04-15 23:02:03: server.c.1513) server started (lighttpd/1.4.59)
readsb          | [readsb] 2022/04/15 23:02:03 rtlsdr: tuner gain set to 49.6 dB
readsb          | [readsb] 2022/04/15 23:02:04 Fri Apr 15 23:02:04 2022 CEST  Waiting for receive thread termination
readsb          | [readsb] 2022/04/15 23:02:04 Fri Apr 15 23:02:04 2022 CEST  Normal exit.
readsb          | [readsb] 2022/04/15 23:02:04 Fri Apr 15 23:02:04 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [readsb] 2022/04/15 23:02:04 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/15 23:02:04 Found Rafael Micro R820T tuner
readsb          | [readsb] 2022/04/15 23:02:04 rtlsdr: tuner gain set to 20.7 dB
readsb          | [readsb-db-update] 2022/04/15 23:02:08 readsb webapp database updated from version 294 to version 296
readsb          | [graphs] 2022/04/15 23:03:03 Initialising graphs
readsb          | [autogain] 2022/04/16 01:02:05 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 02:02:06 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 03:02:07 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 04:02:08 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 05:02:09 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 06:02:11 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 07:02:12 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 08:02:13 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 09:02:14 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 10:02:15 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 11:02:16 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 12:02:17 Insufficient messages received for accurate measurement, extending runtime of gain 20.7 dB.
readsb          | [autogain] 2022/04/16 13:02:19 Reducing gain to: 19.7 dB
readsb          | [readsb] 2022/04/16 13:02:19 Sat Apr 16 13:02:19 2022 CEST  Caught SIGTERM, shutting down..
readsb          | [readsb] 2022/04/16 13:02:19 Sat Apr 16 13:02:19 2022 CEST  Waiting for receive thread termination
readsb          | [readsb] 2022/04/16 13:02:19 Sat Apr 16 13:02:19 2022 CEST  Normal exit.
readsb          | [readsb] 2022/04/16 13:02:19 Sat Apr 16 13:02:19 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [readsb] 2022/04/16 13:02:19 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/16 13:02:19 Found Rafael Micro R820T tuner
readsb          | [readsb] 2022/04/16 13:02:20 rtlsdr: tuner gain set to 19.7 dB
readsb          | [autogain] 2022/04/16 15:02:21 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 16:02:23 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 17:02:24 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 18:02:25 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 19:02:26 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 20:02:27 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 21:02:28 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 22:02:29 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/16 23:02:30 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/17 00:02:32 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/17 01:02:33 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/17 02:02:34 Insufficient messages received for accurate measurement, extending runtime of gain 19.7 dB.
readsb          | [autogain] 2022/04/17 03:02:36 Reducing gain to: 16.6 dB
readsb          | [readsb] 2022/04/17 03:02:36 Sun Apr 17 03:02:36 2022 CEST  Caught SIGTERM, shutting down..
readsb          | [readsb] 2022/04/17 03:02:36 Sun Apr 17 03:02:36 2022 CEST  Waiting for receive thread termination
readsb          | [readsb] 2022/04/17 03:02:36 Sun Apr 17 03:02:36 2022 CEST  Normal exit.
readsb          | [readsb] 2022/04/17 03:02:36 Sun Apr 17 03:02:36 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [readsb] 2022/04/17 03:02:36 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/17 03:02:36 Found Rafael Micro R820T tuner
readsb          | [readsb] 2022/04/17 03:02:36 rtlsdr: tuner gain set to 16.6 dB
readsb          | [autogain] 2022/04/17 05:02:38 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 06:02:39 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 07:02:40 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 08:02:41 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 09:02:42 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 10:02:43 Insufficient messages received for accurate measurement, extending runtime of gain 16.6 dB.
readsb          | [autogain] 2022/04/17 11:02:45 Auto-gain stage 'init' complete. Best gain figure appears to be: 16.6 dB.
readsb          | [autogain] 2022/04/17 11:02:45 Entering auto-gain stage: finetune
readsb          | [readsb] 2022/04/17 11:02:45 Sun Apr 17 11:02:45 2022 CEST  Caught SIGTERM, shutting down..
readsb          | [readsb] 2022/04/17 11:02:45 Sun Apr 17 11:02:45 2022 CEST  Waiting for receive thread termination
readsb          | [readsb] 2022/04/17 11:02:45 Sun Apr 17 11:02:45 2022 CEST  Normal exit.
readsb          | [readsb] 2022/04/17 11:02:45 Sun Apr 17 11:02:45 2022 CEST  Mictronics v4.0.3 starting up.
readsb          | [readsb] 2022/04/17 11:02:45 rtlsdr: using device #0: Generic RTL2832U (Realtek, RTL2832UFA, SN 00001000)
readsb          | [readsb] 2022/04/17 11:02:45 Found Rafael Micro R820T tuner
readsb          | [readsb] 2022/04/17 11:02:45 rtlsdr: tuner gain set to 20.7 dB