I’ve been watching the Solder Smoke direct conversion receiver challenge build and thinking of maybe building it from parts I already have laying around… assuming I wind my own toroids. I haven’t noticed anyone talking about antenna stuff. What is the deal here?
This is the principal video series primer: https://www.youtube.com/watch?v=rLjxU2rMeXw
It is also on hackaday too.
Is there some rule about antenna where a more specialized element is required at specific frequencies? I know I’m missing fundamental practical information here as the wave length for 7 MHz is around 43 meters. Even a quarter wave length would involve a house spanning wire. So what gives, what high school fundamental have I forgotten?
I would see about putting a big loading coil on the antenna when you make it. You would still need a really long wire, but you can at least make the overall antenna length shorter than you otherwise would be able to.