rtl-sdr-scanner-cpp How to squelch / sensitivity?

For me it just records noise no matter if i configure 0.0 or 40.2 gain in the config.

Here are three .mp3 for example but i got 100 in like 15 minutes. It is a zip as i can't upload .mp3 rtl-sdr-scanner.zip

So how to prevent this?

Feb 17 '22 17:02 dandud100

In your case frequency 438.250 MHz is probably in use by something. Many different devices (e.g. temperature sensor, camera, garage door) uses it. Please add frequency to ignore in config.json file and try again. There is not squelch to define, rtl-sdr-scanner do it automatically.

Try add this to config:

"ignored_frequencies_ranges": [
    {
      "start": 438200000,
      "stop": 438300000
    },
]

Feb 17 '22 18:02 shajen

In your case frequency 438.250 MHz is probably in use by something. Many different devices (e.g. temperature sensor, camera, garage door) uses it. Please add frequency to ignore in config.json file and try again. There is not squelch to define, rtl-sdr-scanner do it automatically.

Try add this to config:
"ignored_frequencies_ranges": [
    {
      "start": 438200000,
      "stop": 438300000
    },
]

Yeah i see that now, because you fixed #1 But it is still not fully functional, see following Screenshots

Screenshot1 Webaufnahme_17-2-2022_195027_192 168 178 44

Screenshot2 Webaufnahme_17-2-2022_195043_192 168 178 44

Screenshot3 Webaufnahme_17-2-2022_19533_192 168 178 44

But it is weird i used the very first public version of your cpp scanner and it does not recorded this stuff.

Feb 17 '22 18:02 dandud100

Interesting. Can you show your config.json file? Please test on the latest version.

Feb 17 '22 18:02 shajen

Interesting. Can you show your config.json file? Please test on the latest version.

I use the latest.

My config.json

{
  "scanner_frequencies_ranges": [
    {
      "start": 433075000,
      "stop": 434775000,
      "step": 25000
    },
    {
      "start": 446000000,
      "stop": 446200000,
      "step": 125
    },
    {
      "start": 456840000,
      "stop": 457020000,
      "step": 125
    },
    {
      "start": 457220000,
      "stop": 457400000,
      "step": 125
    },
    {
      "start": 467220000,
      "stop": 467400000,
      "step": 125
    }
  ],
  "ignored_frequencies_ranges": [
	{
      "start": 434400000,
      "stop": 434400000
    }
  ],
  "device": {
    "ppm_error": 0,
    "tuner_gain": 40.2,
    "bandwidth": 2000000
  },
  "recording": {
    "range_scanning_time_ms": 100,
    "max_silence_time_ms": 2000,
    "min_recording_time_ms": 1000,
    "sample_rate": 48000,
    "threads": 4,
    "enabled": true
  },
  "output": {
    "recordings": "sdr/recordings",
    "logs": "sdr/logs",
    "file_log_level": "info",
    "console_log_level": "info"
  },
  "server": {
    "address": "0.0.0.0",
    "port": 9999,
    "key": "",
    "threads": 4
  }
}

Feb 17 '22 18:02 dandud100

I tested it and your config works ok with my rtl-sdr scanner on latest version. The frequencies on your screenshots are different that you posted in config.

Feb 17 '22 19:02 shajen

I tested it and your config works ok with my rtl-sdr scanner on latest version. The frequencies on your screenshots are different that you posted in config.

Yeah, you are right, i just found this out in the second you answered. It just does not use my config, if i run it manually it does but with my systemd / systemctl service it does not. What is wrong?

[Unit]
Description=rtl-sdr-scanner

[Service]
User=pi
WorkingDirectory=/home/pi/
Type=exec
ExecStart=/home/pi/rtl-sdr-scanner-cpp/build/auto-sdr config.json
Restart=always
RestartSec=10s
OOMScoreAdjust=-500

[Install]
WantedBy=multi-user.target

Edit: Fixed it by changing following: WorkingDirectory=/home/pi/rtl-sdr-scanner-cpp/

I think you should add a warning to the log that says config.yml not found or so. :)

The waterfall thing is still very slow, i dont know if this is normal. Webaufnahme_17-2-2022_204335_192 168 178 44

Feb 17 '22 19:02 dandud100

Pass full path to config.json. Probably the path should be like this:

ExecStart=/home/pi/rtl-sdr-scanner-cpp/build/auto-sdr /home/pi/rtl-sdr-scanner-cpp/config.json

Feb 17 '22 19:02 shajen

It will work slowly, because every switch between frequencies range takes about ~100 ms. So you should definitely choose as few frequency ranges as possible to speed it up.

But if the scanner finds an active frequency, it records it without switching as long as the signal is active.

Feb 17 '22 19:02 shajen

and the squelch question?

Tried to set max recording time. But no change.

"recording": { "range_scanning_time_ms": 100, "max_silence_time_ms": 4000, "max_recording_time_s": 30, "min_recording_time_ms": 3000, "sample_rate": 48000, "threads": 4, "enabled": true