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?
if you have an antenna with impedance of, say, 200 ohms, then you need to match it to transmitter impedance of 50 ohms, or else most of power output from transmitter would be bounced back and will damage output stage of amplifier. because on receive currents are tiny, you can wing it by just using it without any match and connecting it directly