Mike assembles a Buck/Boost converter device for use with QRP operations. George shows how to make a high quality 4:1 Balun. Tommy builds the M5 Ham Radio project. https://amateurlogic.tv
Hi Guys, Although mix 31 will work, the cores will generate slightly higher insertion loss, be less efficient and generate more heat due to the high permeability (1500). Great for choking, suppression etc but not real good for use in more than a 1:1 . Mix 43 would be a better (permeability 800) but best would be mix 52 or a K mix. FYI, there is no need to insulate the cores using tape especially if you're using wire inserted in Teflon tubing. You should also separate the two cores by a minimum of 1/4" to eliminate the interaction of the flux generated by each core. Here is a link that will offer more info. Bob, KZ5R Balun Designs
Looking forward to the follow-up on the buck/boost RFI. I’m working on a project using a Buck converter to drop 12VDC down to 5V to power my RPi4 with an SDR. My big concern is RFI generated by the buck converter. Thanks guys for the informative video.
Hi, I have read your comments and liked the way you have responded - thanks. Could I ask a question? I Love QRP and would like to a "non-random" Random Wire antenna. The ones I have used I have built my own 9:1 Unun's - the issue I have is when trying to use 80 Meters or 160 Meters any the core for the Unun? Is there a core that is usable for this that would be better that the 43 mix I have? I would appreciate the assistance and comments you may have. Thanks Dave M7CJD
