First things, I do not understand toroids and I hope to change that someday. I need to make a switchable balun like the Elecraft BL2 Balun. It is switchable between 1:1 and 4:1 . In my junk box I have T50-6 toroids and T68-6. Is it possible to make 1:1 and 4:1 baluns with these toroids, if so how do I determine the number of winding's. It will be for QRP power levels only with no more than 10 watts for SSB.
First of all, powered iron cores DO NOT make good current baluns. You MUST use ferrite. Want to learn all about baluns? Read this: http://audiosystemsgroup.com/RFI-Ham.pdf The ARRL hand book or ARRL antenna books are both good places to learn about baluns. No matter how you slice it, "Use Ferrite !" Barry, KU3X www.ku3x.net
Best lecture I've ever attended was Roy W7EL presentation on baluns that he gave at WVDX club meeting. That article should be in every hams collection