@sun @whiteline @ageha Maybe they don't refuse, they just are no longer smart enough to do anything. It's like how I tried to make an FIR filter. I've read the classic Lyons textbook, understood almost nothing. I then tried to use libraries that composed a few sample filters. Learned that the selectivity is unacceptably poor if you do that without knowing the initial parameters, but those can only be found by some extremely arcane methods like Phil or whatever. At that point I gave up and went back to hardware receivers with coils and capacitors.