Permeability Tuning

[pwdrive]

Well a bit of progress, I have found out that the Barlow Wadley receiver used a single ferrite slug for the RF bandpass filter tuning (via switched coils all on the same former) covering the full shortwave spectrum, question now is what grade of ferrite did they use? and is it likely to be pretty broadband given the nature of the Wadley loop system?

Lawrence.