Step Sizes

[scancapecod]

First off thanks for creating this, very cool! I have it running in an Ubuntu 22 VM in VMWare. I am not an experienced Linux user but following your instructions I believe I have updated to the new version released today.

My one stumbling block with this is the step size. I guess I am just not wrapping my brain around the concept. In the USA, there is a 7.5 kHz step in the VHF-HI band between 154.650 MHz and about 156.240. 7.5 kHz steps fit that range fine but I can't see any way, especially in the new version, to make that step work. Having to go through that band with 1 kHz steps is not ideal.

Same with any UHF traffic, where the step can be either 6.25 kHz or 12.5 kHz. For example, I should be able to search 482.000 MHz to 484.000 MHz with 12.5 kHz steps as they fit into that span. 1 kHz steps are not logical here either.

Other than that this is a very impressive program. When AM mode is added for aircraft band reception that will be fantastic, but again here in the US in the VHF Aviation band of 118-137 MHz the step size is 25 kHz.

Hopefully I'm just being a dummy with figuring this out; it's entirely possible and/or quite likely!

Thanks, Scott

[shajen]

step is related directly to sample_rate and fft. I mean that step = sample_rate / fft. More here.

So for sample_rate = 2048000 Hz and fft = 4096 step is 500 Hz which is divider of 12.5 kHz so you transmissions should be detected.

So, to scan 482.000 MHz - 484.000 MHz with step 500 Hz step you have to use config:

{
  "scanner_frequencies_ranges": [
    {
      "device_serial": "auto",
      "ranges": [
        {
          "start": 482000000,
          "stop": 484000000,
          "sample_rate": 2048000,
          "fft": 4096
        }
      ]
    }
  ]
}