I was going through some old shack photos, and ran across this “Magic Smoke Moment” from 2012. The 4:1 current balun on the left was wound on an FT240-31 ring–I did not build it, it was a Fleabay discovery similar to the glut of BH7JYR baluns and ununs offered today. It worked fine for nearly a year into a 134′ doublet, never seeing much more than 500W sent to it by an updated Heathkit SB-200, and it competently worked over 50 countries.
Then came the ‘new’ Amp Supply LK-500ZBY linear, found for $400USD at the dead-dog end of the RARA Rochester, NY hamfest. The maker of the balun claimed 1KW rating. Right…
The replacement balun on the right is wound on a genuine Fair-view FT400-31 ring. Big difference, right? The balun on the right is shown next to the old burnt up one–a year later on the bench for annual cleaning. It saw 1KW quite a lot…
Size matters.
