Hello, after NXP discontinued the SA602A we designed a compatible chip for the continued production of the NanoVNA. This chip has a slightly lower noise figure, but also a slightly lower IIP3. I modified the circuitry of the NanoVNA-H and NanoVNA-H4 to accommodate these new chips. the difference in effective dynamics between the NanoVNA-H4 V4.4 and the NanoVNA-H v4.3 is not very large, the main difference is a slight improvement in the dynamic range below 100kHz.
