WA3TFS SDR Upverter Design - Land Boards Wiki
DIY SDR HF Up-Converter by WA7JHZ: Another good choice for your RTLSDR.
HF Reflection? : r/RTLSDR
RTL-SDR V4 TCXO + SMA + Bias-T USB key with R828D tuner
How can a software-defined radio be used in a radio station? - Quora
Realtek RTL SDR £15 Dongle Explored
RTL-SDR Blog V4 dongle launched with Rafeal R828D tuner chip - CNX Software
Ham It Up v1.3 - Listen to HF on Your RTL-SDR, No case Assembled PCB only (0.5MHz to 50MHz)
Ham It Up v1.3 - Listen to HF on Your RTL-SDR, No case Assembled PCB