I’ve been wanting to built a good 4:1 BalUn as part of the never ending project that is my HF antenna system for some time and today, I finally got around to the job. This is a “true” 4:1 Current BalUn that is wound as two separate 1:1 current baluns and then placed together to create the 4:1 ration. Any 4:1 built on a single core that claims to be a current BalUn is lying and is actually a Voltage BalUn!
Heres what I used:
2 x 80cm lengths of 15A twin cable
2 x FT240-43 Toroids
1 x N connector
2 x binding post
1 x waterproof box
And here are the photos:
Parts ready for construction:
Toroids wound:
Toroids stacked and soldered ready for testing:
4:1 BalUn being tested before final assembly:
