Toroid for use as HF/VHF balun, unun
A professional-grade core selected and tested by SOTABEAMS for 125 Watt 1:1 and 4:1 baluns; 3 - 50 MHz.
This is the toroid we use for the 1:1 balun in Bandhopper linked dipole antennas - in our opinion it is the smallest and lightest core that should still manage to do the job, so a decent choice for portable use up to 125W.
For higher power use, or if you would like a larger choking impedance, the cores can be stacked, or we do sell larger toroids of the same material (FT140-43 and FT240-43). These toroids are also great for combatting RFI problems.
Toroid cores are brittle so avoid banging them against hard surfaces.
Toroid core weight = 14 grams
OD = 29mm 1.14" ID = 19mm 0.748"
Material: ferrite, type 43.
1:1 Baluns should be wound as shown in the diagram below.
Each pass through the hole in the toroid is a turn.
For 50MHz 3 + 2 turns of RG58 is recommended.
For HF 7 + 6 turns of RG174 is recommended.
Hold the ends in place with cable ties.
This diagram shows 4 + 3 turns, 4 on the left and 3 on the right.
The crossover through the centre is not counted in the left or right sets of turns. The crossover is symmetrical, so there is no particular reason to include it in one set rather than the other. But since the crossover does pass through the hole in the toroid, the total number of turns is technically 8 (4+3, and +1 for the crossover).
The exact number of turns is not critical, there just have to be enough to give sufficient common mode impedance at the lowest operating frequency.
7 Reviews Hide Reviews Show Reviews
Nice example, easy to wind with instructions shown on the website. Not actually in use yet, but I’m sure it will work well as a 1:1 balun. Good deivery & service.
I like to make my own dipoles etc and having purchased these Toroid’s I find them very useful and can take up to 100w . Fast delivery. Recommended
I bought this to make my own 9:1 UnUn for my end-fed wire antenna. It was big enough to get the necessary number of turns which was helpful. Basically it just works! The UnUn tames the impedance so that I can tune 160 - 12 m. I would certainly buy it again.
I have used some of these rings instead for FT 118-43 and it seems to be similar values.
This is the real deal, good quality toroids at the right price.They come well packaged ready for my project.
The toroid do the job. Not a fake toroid as many in today's market! 1:1 to 1:1.3 from 3.5 to 28 Mhz. Happy with it and I would buy again if necessary.
Just the job. Light weight and easy to wind. Gave a 1:1 on 80m with no real measurable return current. 1.3:1 on 10m both at 100W Happy with that. Would recommend this core to others