Toroid Core FT240-43 Ferrite

It's a Toroid, it works, good price, I'm happy

Works well in coaxial RF choke for 20 thru 6 meters.

Perfect for my projects. I built a transformer for an antenna system with these and they are holding up great, stack 2 or 3 and you'll be set. Great value, easy, and work as intended when used in your project. It knocked out some stray RF on my laptop USB that would disconnect from my radios with every transmission.

These are perfect for building current mode balun and 49:1 unun. Stack 2 or 3 of them for the most efficient 49:1 unun on your EFHW.

I've made several 49:1 and 64:1 ununs with these ferrites. They work as expected and are a quality product with no rough edges or abrasions.

If you're looking for a solution to your HF issues you should get ferrite No.43 but a lot of sellers don't specify what ferrite they are actually selling. Because of this I've bought some way less expensive core's that did not work. This one, from Fair Rite, DOES. I bought one to try out, and it worked as expected so I bought 2 more. I guess my location was close so I received the item as if it were PRIME. The item(s) were well packed to insure the product would arrive unbroken. I am happy.

Great toroid core with the proper quantum flux transfer ratio well within the bounds of permeability and functional field current control that I imagined in my mad-RF-scientist lab notes.

These are good toroid cores. Made a couple of chokes with these and they are working extremely well for me. I will be purchasing more.

El producto llego en buenas condiciones, despues de construir el transformador funiona a la perfeccion gracias Amazon.

Excellent genuine FT240-43 Ferrite Cores, good fast delivery as well,recommended purchase.

I used the FT240-43 ferrite toroid core in my balun build, and it performed exactly as I hoped — solid, reliable, and very forgiving for amateur builds. The 43-mix material offers good broadband performance, making it ideal for HF baluns that cover a wide range of frequencies without excessive loss. Winding onto the core is straightforward even for larger gauge wire, and the core’s smooth surface makes it easier to dress the turns neatly. Once assembled, the balun exhibits low loss and stable impedance transformation across the intended HF range. That translates into improved SWR and cleaner feedline current, especially noticeable on multiband antennas. Pros: • Great broadband performance: Works well across HF bands with minimal loss. • Easy to work with: Winding and handling are straightforward even with heavier wire. • Consistent results: Baluns built with FT240-43 show stable, predictable performance. • Good for HF & multiband: Excellent choice for 1:1 current baluns, 4:1 impedance transformers, and similar builds. Cons: • Not ideal for VHF/UHF: Ferrite #43 isn’t optimized for higher-frequency VHF/UHF applications (but for HF baluns it’s spot on). Overall, the FT240-43 toroid core is a reliable, high-value choice for any ham radio or antenna project that needs a quality ferrite core balun. I’ll definitely be using more of these in future builds.

Used to fabricate an EFHW transformer.

Just the job