Detecting a jamming signal?

[Ulric Von Bek]

I have a FineOffset WS3083 and rtl_433 picks this up perfectly. I do get regular disturbances on the base station which I think are due to jamming signals from a HackRF device which is being operated locally. These cause big anomalies in the station data and sometimes crash the base station. I'd like to be able to detect and log the jamming signals so that I can automate a restart and perhaps cleaning up my weather logs. It seems that a jamming signal would have no identifiable signature other than just a burst of noise. Is rtl_433 the right tool for this? Can it be detected and logged for timing and duration? Are there Flex Decoder settings which might do this for me?

[Greg Troxel]

rtl_433 is not the right tool. The problem is that "jamming signal" is
undefined and you are looking to discover and characterize a signal that
you think might exist but at this point you don't know.

I would suggest trying to record iq samples, and visualize as a
waterfall, and see if you can identify a pattern and then move the
receiver to localize it

[Ulric Von Bek]

The signal seems to be of very brief duration and occurs often in the small hours of the morning. I have spent days watching waterfalls and not caught one yet. I have disconnected the solar sensors from the weather station and the signals do seem to leave an artefact on the base station. UV Index will be a positive integer between 1 and 3. Solar radiation will be one of two values 478 or 1662W/m2. These occur in the middle of the night but if I leave rtl_433 logging all night, it detects nothing. The base station is still affected though. It is a perplexing problem. The problem is that I don't know if the numbers I see are part of the signal or simply an artefact generated by the response of the base station to jamming. I know it is not an equipment fault because I set up a second base station on a different PC using different software and it records the same anomalies.

[Ulric Von Bek]

Yes, I think you're right. Code is not a problem - I've done quite a lot of work in Python and SQL. It is radio devices which are outside my experience. I guess what I'm looking for is a way to automate capture of a likely signal during hours when I'm normally fast asleep. Thanks for your comments. I need to do some more thinking about how to do this.

[Benjamin Larsson]

On 12/08/2023 16:44, Ulric Von Bek wrote:
> Yes, I think you're right. Code is not a problem - I've done quite a lot
> of work in Python and SQL. It is radio devices which are outside my
> experience. I guess what I'm looking for is a way to automate capture of
> a likely signal during hours when I'm normally fast asleep. Thanks for
> your comments. I need to do some more thinking about how to do this.
>

You can use the signal recorder. -S unknown

It will capture everything it does not recognize. If there is a jamming
signal it will be represented with several sequential large recordings.

MvH
Benjamin Larsson

[Ulric Von Bek]

If I use rtl_433 -S unknown, can I direct that output to a particular directory? Where do the files end up?