RTLSDR-Airband VS wmbusmeters

You're all correct, except there are not that many $30 SDRs out there. Also, most SDRs have clearly superior capabilities to the RTL-SDR, though those capabilities often are not required.

BTW, for simple AM/FM demodulation I cannot recommend enough the handy https://github.com/charlie-foxtrot/RTLSDR-Airband. For example most of LiveATC.net feeds run on it.

rtlsdr_airband, but again requires knowing the frequencies of interest ahead of time.

You may want to give RTLSDR-Airband a look. Its designed for analog AM/NFM voice traffic and can be configured to operate on any frequency your rtlsdr dongle can handle. It can also be configured to output to an mp3 file, in addition to other things like IceCast.

There’s an example service config file in the repo: https://github.com/charlie-foxtrot/RTLSDR-Airband/blob/main/init.d/rtl_airband.service

I have been streaming the output from RTLSDR-Airband (https://github.com/charlie-foxtrot/RTLSDR-Airband) with icecast2 for several (5?) Years now, and I have some time and inclination to look at reducing latency (currently best is 10s, but often much more.)

https://github.com/szpajder/RTLSDR-Airband Might be what you are looking for, although I don't know the performance requirements. It has a scan mode detailed here: https://github.com/szpajder/RTLSDR-Airband/wiki/Configuring-channels-for-scan-mode

It's possible you do not even need a meter. You can often read the utilities meter https://github.com/wmbusmeters/wmbusmeters

$ git clone https://github.com/weetmuts/wmbusmeters.git $ cd wmbusmeters $ ./configure $ make $ sudo make install $ sudo systemctl daemon-reload $ sudo udevadm control --reload-rules $ sudo udevadm trigger

The smartmeters installed by Waterlink in Flanders are Kamstrup Multical 21 and they broadcast every 96 seconds a wireless M-BUS message (on 868 MHz) with the latest data. It's easy enough to receive the messages thanks to wmbusmeters (and those of my neighbours, as well as messages from gas meters) but of course (and thankfully) they are encrypted. Users in Norway (or Sweden? I'm not sure anymore) seem to receive the ".kem" file corresponding to their meter that allows them to decrypt messages.