Nova SDR and 2m band

[gsasa]

Hello everyone. I am new to the world of Web SDR software. I am from Bosnia and Herzegovina. I have a Nooelec NESDR SMArt v5 device. As a blind person, all Windows softwares are inaccessible to me with screen readers. Your Nova SDR is one of the most accessible SDR softwares for screen readers. I want to, for a start, set up my own private web sdr server. Once conditions are met, I would like to make it public on the internet. I have compiled the application on a Raspberry Pi 5 with 8 GB of RAM and Raspberry Pi OS Lite based on Debian Trixie. To begin with, I want to create a profile for the amateur 2m band, 144-146 MHz. However, I have a problem. When listening to traffic, I hear hum and crackling in the speakers, and the voices are very quiet. Do I need to send you the contents of the receivers.json file? Please note that clFFT acceleration is activated. Kind regards.

[Steven9101]

Yes, please send the configuration and maybe attach a video example

[gsasa]

Hello. This is the content of my receivers.json file. ` GNU nano 8.4 ./config/receivers.json
"waterfall_size": 2048,
"waterfall_compression": "zstd",
"audio_compression": "opus",
"smeter_offset": 0,
"accelerator": "clfft",
"driver": {
"kind": "soapysdr",
"format": "cs16",
"device": "driver=rtlsdr, label=Generic RTL2832U OEM :: 83540205, manufacturer=Nooelec, product=NESDR SMArt v>
"channel": 0,
"agc": true
},
"defaults": {
"frequency": 145675000,
"modulation": "FM"
}
},
"defaults": {
"frequency": 145675000,
"modulation": "FM",
"squelch_enabled": false
}
}
]
}

` Attached is also a recording of how the Nova SDR works with me. I note that I tried to get a signal with manually adjusted values in overall gain and LNA gain, but I couldn't get anything. What I got was with AGC turned on. https://drive.google.com/file/d/1fg1flmJQJsFmnV3I-JjvIzuICnmLTQmY/view?usp=sharing

[gsasa]

I forgot to mention that I switched the Pi5 processor to performance mode and the crackling went down. It's almost gone. All that remained was noise and hum.

[gsasa]

Today I connected the Pi5 to a premium powerbank (Anker Prime) that can power this computer. The hum and light crackling persisted while using Nova SDR. This proves that the problem is not in my electrical network. However, I noticed that this hum is not present when I use OpenWebRX+ on the same hardware and antenna. This suggests that the issue might be related to how the software handles the SDR signal or audio processing.

[Steven9101]

Hey, the is the HUM gone when using the mode FMC?

[gsasa]

I'm not sure that it disappeared, but I can try again.

[gsasa]

When FMC is active, the sound is much better. The hum is barely audible. I think I set FMC under modulation in receivers.json in both places. However, when the browser loads the page, it still sets modulation to FM. Here's another video for you. At first, it starts with FM, then I manually switch to FMC and you will hear the difference. https://drive.google.com/file/d/1hJTiV2cR0u19f6tiw0TXPdv7tE4DDPyF/view?usp=sharing

[gsasa]

This is new receivers.json file. ` GNU nano 8.4 ./config/receivers.json

    "waterfall_size": 2048,

    "waterfall_compression": "zstd",

    "audio_compression": "opus",

    "smeter_offset": 0,

    "accelerator": "clfft",

    "driver": {

      "kind": "soapysdr",

      "format": "cs16",

      "device": "driver=rtlsdr, label=Generic RTL2832U OEM :: 83540205, manufacturer=Nooelec, product=NESDR SMArt v>

      "channel": 0,

      "agc": true

      },

    "defaults": {

      "frequency": 145675000,

      "modulation": "FMC"

    }

  },

  "defaults": {

    "frequency": 145675000,

    "modulation": "FMC",

    "squelch_enabled": false

  }

}

]

}`