Quote:
Originally Posted by bob91343
Note that there is no variable tuning capacitor. It moves slugs through coils to tune. A spinoff of the Dumont Inductuner or the Collins PTO.
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This concept was probably derived from the Dumont Inputuner. I have three Zenith radios (K731, C845 and Royal 3000-1) that use permeability-tuned coils for FM tuning, no tuning capacitor for that band. There is a tuning cap in each radio, but it is used strictly for AM (and shortwave in the 3000-1). The sensitivity of all three sets is excellent, probably due in large part to the permeability-tuned FM front end.
BTW, I did not realize that Collins also used such tuners in their amateur gear, and I've been in ham radio over 40 years (just renewed my license for another 10-year term). Never could afford Collins gear, but I remember seeing it advertised in QST, and back when the ARRL Handbook had an advertising section way in the back of the book.