One often sees people ask for help in choosing a ferrite mix for a particular application. A recent thread on social media asks for help designing a unun for the 1.8MHz amateur band, and it has provided the opportunity for participation, even if the content was not good.
An important early step in designing a ferrite cored transformer is to find a combination of ferrite material, core geometry, and number of turns to deliver acceptable core loss at the lowest desired frequency.
Design of a transformer to cover just the 1.8MHz ham band is a relatively simple exercise. Continue reading Choosing a ferrite mix for a 160m unun rationally