Component level (mostly analog) electronics from microwave to AF. Jazz guitar and guitar amplifiers. Radio astronomy.
The story of life as a hobbyist builder --- you get this email from a vendor from whom you buy parts:
Yes, that situation happens quite often. Sometimes I am not sure if we hobbyists are just not good at developing circuits with contemporary parts or if the electronics component market is just that volatile. I even have some newer designs with newer components where just a few months later parts became obsolete.
Thanks Sebastian. I'm currently studying double-balanced mixing and multiplying via emitter coupled pairs (Gilbert Cell, etc.) Digi-Key does not have any old-school Gilbert cell type mixers in their Canadian catalogue. Even the more modern multipliers & quadrature mixers are falling in to relative obsolescence in this 5G digital world. My Samsung Android smart phone contains 1just receiver IC. For for voice or data, digital Quadrature Amplitude Modulation (256 QAM) gets employed. Either 2 analog signals, or 2 digital bit streams get amplitude modulated with amplitude-shift keying or digital amplitude modulation respectively. The two carrier waves of the same frequency are in quadrature and processed digitally at amazing speed with circuitry/code to tweak gain and phase to endure low I/ Q imbalance at baseband. All of this really makes me feel obsolete! By the way , I like your blog: https://baltic-lab.com/