To get an idea about radios, I made a crystal radio when I was in 7th grade, I only had few components. The only component I had difficulty in getting was the crystal oscillator (I was living in a rural town). It was mind blowing when I first heard the audio through IEMs ! It felt magical that this contraption was working without any battery source.
You can use a germanium diode or even Shottky now instead of a “crystal”. 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 ca…
Also I had seen some recon antennas in a certain campus (can't say much about that) when I was a kid. Those were like long wires hanging from towers. I believe they used to receive/decode SW/AM signals from far away. I realised this much much later in my life. But fascinating nonetheless. And adding to all these is SDR! That's a whole different thing.