rtl-sdr.com

You'll need a diplexor. Generally the antennas sized for VHF/UHF do not work well for HF however.

The included antenna is not sized for HF, you'll need a much larger antenna for that. There is already a good FM filter on the direct sampling circuit, so you shouldn't need another unless you're very close to an FM tower. For the AM band you can expand the long elements almost to the max for best p...

You've got the gain at maximum, is this where you get the best SNR?

Also are you sure that you have the LNA powered?

Got a screenshot of what your spectrum looks like during a pass? You need to use NFM or WFM mode (WFM mode usually works better), and definitely not AM mode. The filter size should be just large enough to cover the signal, at least 34 kHz. So - the issues. When using RPi 4 with either of the dongles...

V3 Pro

This is a cloned unit, so I can't offer any support if it's a hardware issue. But even if it's working fine, you do need a properly sized HF antenna for it to work.

It shows two bulk in devices normally. Zero is the SDR/radio itself, One is the InfraRed endpoint which is not used for SDR. You don't need to do anything.

Are you maybe referring to KerberosSDR? Please ask in the appropriate forum if you are.

With dec and FIR filtering off, you should check the spectrum and see a single nice peak (assuming there are no other signals being received). If it's overloading from too much gain/signal, then you'll probably see multiple peaks with weird shapes. Also one more thing I forgot to mention, don't forg...

Are you trying to connect to the hotspot generated by the Pi, or have it connect to a hotspot generated by your phone?

Very nice! Have you managed to confirm DFing after adding those switches? No phase distortion?