Total posts : 45366
Excellent answers everyone, and just the sorts of things I’d been wondering about. Being more of a dabbler than anything else, I referred to the cores in am radios as being “ferrite” without checking any references to see what they’re actually made of.
I’d just gotten back onto these ideas a bit from the talk about the talking house using a moving core inductor for tuning, and also from taking a look at some of the “dx” style crystal radios some folks make. I’d been toying with the idea of talking my daughter into tackling a crystal radio project (or doing one with me), and was thinking of the possibilities for building some interest in the switch to am. A friend of mine who is well outside the range of my current little FM rig is being very hopeful of AM, since he has an old floor model RCA Victor (IIRC) reciever that seems to pick up well. So some of the parts and techniques from crystal radios, like variometer tuning had been running through my head.
But in any case, great answers to the questions!