Such a simple radio can be a gateway drug to a very complex and deep hobby. In my case it went like that:
1. Built a simple radio
2. Could hardly hear anything, need to add an amplifier to it 3. Now it’s better but captures a lot of noise
4. Design a filter to select just that one station
5. Now I want to listen to more stations.
6. Ugh, you can’t design a good filter with variable frequency. Enter the superheterodyne world.
7. Now finally got something that resembles a tunable AM radio, but it kinda whistles / hums a lot. Ah, so the mirror image is a real thing?!
8. Need a higher IF to be able to better reject the image before the mixer. Ok, let’s make a double conversion superhet then.
9. Buy a set of ceramic filters and play with them to get the best selectivity.
10. Try to add more amplification only to learn if you go too far you get an oscillator instead of an amplifier.
11. The sound level is not stable. Add AGC.
12. Pick up some stations from 5000+ km away. Nice. But there is some weird distortion. Oh, I’ve been a culprit of frequency selective fading…
Fast forward and now I’m building a PLL synchronized AM product demodulator with a squaring loop for carrier recovery.
Fun. Lot of fun! Wholeheartedly recommend!