Can Pi SDR IQ/IQ Plus work without a local ethernet network?
Yes. Even if you do not have a local ethernet network around with router or network switch, Pi SDR IQ/IQ Plus can be fully utilized with just connecting a ethernet cable from your PC's ethernet port, directly to Pi SDR IQ/IQ Plus's ethernet port. As simple as that you could have a non-networked PC with Pi SDR IQ Plus fully working setup, no local ethernet network needed, just one cable.