G'day all, yes I know that this subject has been 'done to death', as it were yet the more that I read (on the internet mainly), the more confused that I sometimes get! Yes I know that the subject is constantly evolving, however quite a bit that I read (on the 'net), is essentially wrong in the technical sense. For example I still see powdered iron core material recommended for simple 1:1 choke baluns when it is inherently very low permeability severely limits its low frequency performance. Ferrites are 'always' better! Speaking of 'ferrites', I am endlessly baffled by the many different 'mixes' that seem to be the 'flavours' of the month! My favourite 'balun' book is Sevick's 'Transmission Line Transformers' 3rd edition, and although somewhat dated now, has all the required reference material that I need, and regarding ferrites per se, the 61 material (ui 125) is recommended for many of his designs (including the lowest loss) and many of my own DIY designs are modelled on Sevick's designs, and in many cases, and are wound on 125 ui ferrite rods and work perfectly. So why is the present balun state of the art so seemingly complex and involved when it doesn't apparently need to be? Regards, Felix vk4fuq.