I have a certain fascination with the old homebrew tube rigs. At some point, I want to build a superhet with the tubes standing proudly on top with their soft glow visible and the guts hidden below... something like how the high end tube audio amps are packaged today. Why hide all that light and hand blown glass, right?
To the question... so many of these designs used tank circuits and IF transformers with either hand wound form coils or TV parts. Is there any reason why a toroid couldn't be used in place of an air core coil? They are much more elegant IMHO. If one knows the frequency and capacitance, you could solve for the inductance, use a toroid calculator and wind it in a smaller package, right? Also, since many of the inductors had the ability to trim (with the LC circuit having fixed capacitance), couldn't you also trim the resonant frequency on the capacitance side rather than the inductor side using a trim capacitor? My newbie impression is this is an old school versus modern approach but achieves the same end. Yes or no?
Any thoughts or comments on the 1960 ARRL DCS-500 Superhet? This is what got me thinking, modified using a switchable filter selector rather than a rack full of air coils to switch out. Or, something like the HBR 14. I realize that either would be a quite ambitious project but dreaming and thinking on it doesn't cost much.
Jon - KJ6TJX