A really nice remote tuning capacitor circuit for a receiving mag loop
I really like the simplicity and direct feedback of this circuit – that uses variable diodes – NTE618. The circuit can be found on this web page – https://www.randombio.com/loopantenna.html
I’ve done enough testing with the loop – at its lowest usable frequency, but I only took one quick test on 40M, and they sounded dead. I will be getting the Wellbrook ALA100N preamps tomorrow, so will test after they are inline, but I also expect that a tuned circuit at the antenna will offer better multi band performance.
My goal up through last weekend was to settle on the physical characteristics of the loops – and I’m very pleased as is. What I have in the back yard is really a “platform” for further experimentation with these receiving mag loops.