Hi Ogden
i did look at Wiki but found it to complicated for me (I am not being critical hear )
OK we have 3rd order intercept for mixers & amplifiers but when evaluating a spectrum analyser i would probably not measure any of its internal signals nut compare
shoulder width and noise levels on signals
regarding the The TinySA ideal training and a nice tool to start with and for most good enough as most do not go above 1000 Mhz
regarding VNA i decided i did not require a full VNA system at home as it takes up a big chunk of space but the NanoVNA is defiantly worth looking at regarding the line
(I do not agree to armchair experts suggesting SDR as viable replacement for Spectrum Analyzer. SDR is spectrum indicator at best. Most of SDR software do not cover even fraction of measurements available on decent spectrum analyser, even low-end from Rigol/Siglent.)
I totally agree with this line but then I do run 2 systems of HP 70000 spectrum analysers that are not budget items but the big problem with lab equipment is it is BIG
and so small is often the solution for most so just enjoy your time with electronics
as Test Equipment can be a game by itself as you then require test equipment to test the test equipment
regards Paul