rtl_433 not working on older rtl-sdr device with new librtlsdr

[acsawdey]

I have two SDR devices, a RTL-SDR Blog V4, and an older one I got from Adafruit (https://www.adafruit.com/product/1497).

What I am seeing is that rtl_433 will only work with the V4 if it is built using the new librtlsdr from their git, and it will only work with the old device if I build it with the "0.6" librtlsdr that raspbian or ubuntu 22.04 have. The other combinations, it builds and runs but I never receive any signals. rtl_adsp on the other hand works with either device and either library.

[waltje]

I cannot get it to work at all with my V4. Yes, using the new rtlsdr.dll driver it sees it, but it will not proceed to setting the frequency:

C:\Program Files\RTL433>rtl_433-rtlsdr.exe rtl_433 version 23.11 branch at 202311281352 inputs file rtl_tcp RTL-SDR Found Rafael Micro R828D tuner RTL-SDR Blog V4 Detected [SDR] Using device 0: RTLSDRBlog, Blog V4, SN: 00000001, "Generic RTL2832U OEM" Exact sample rate is: 250000.000414 Hz

When started with the old rtlsdr.dll driver, it will report 'failed to set frequency' (as expected.)

[zuckschwerdt]

Can you run with -vvvv to get debug messages? Also -Y autolevel -Y magest -M level -M noise to see what the input data looks like?

[waltje]

I did. Interestingly, in debug mode, it does show it is tuned to 433.92.

rtl_433 version 23.11 branch at 202311281352 inputs file rtl_tcp RTL-SDR Found Rafael Micro R828D tuner RTL-SDR Blog V4 Detected [SDR] Using device 0: RTLSDRBlog, Blog V4, SN: 00000001, "Generic RTL2832U OEM" Exact sample rate is: 250000.000414 Hz

in normal mode. Using the old (original) driver, it says "Tuned to.." here. I guess that comes from the driver then, and not from the application itself.

The debug log shows:

[SDR] Found 1 device(s) [SDR] trying device 0: RTLSDRBlog, Blog V4, SN: 00000001 [SDR] Using device 0: RTLSDRBlog, Blog V4, SN: 00000001, "Generic RTL2832U OEM" [SDR] Sample rate set to 250000 S/s. [Input] Bit detection level set to 0.0 (Auto). [SDR] Tuner gain set to Auto. [Input] Reading samples in async mode... [SDR] rtlsdr_set_center_freq 433920000 = 0 [SDR] Tuned to 433.920MHz. [acquire_thread] acquire_thread enter... [Auto Level] Estimated noise level is -16.8 dB, adjusting minimum detection level to -13.8 dB [Baseband] low pass filter for 250000 Hz at cutoff 25000 Hz, 40.0 us

so that looks good.

So, nevermind my comment on it not working. It does, although you probably do want to include the new rtlsdr.dll file which also supports the V4 dongle.

[waltje]

I think this can be closed.

I built the code from source, using the new libsdr, and it seems to work fine on both my V4 and V3 units.

[zuckschwerdt]

Thanks for the feedback, yes, there is no clear indication that rtl_433 uses the libs in an incompatible way.