Overview: The FT-140-43 ferrite toroid set includes two ring-shaped cores in the FT-140 footprint, fabricated from a type-43 ferrite formulation intended for broadband radio-frequency suppression. These toroids are intended for use on EFHW antenna feedlines, baluns/ununs, power transformer windings and other circuits where stray RF or conducted EMI must be reduced.

Materials and construction: Each core is molded from high-permeability ferrite material with mechanical robustness and thermal tolerance for typical electronic and industrial environments. The surface receives a protective finish that resists corrosion and handling wear, extending service life and lowering the need for replacement. The FT-140-43 material exhibits characteristics tailored for interference attenuation across HF and related frequency ranges.

Dimensions and contents: This offering contains two FT-140-sized toroidal cores (the standard FT-140 geometry and profile). The ring form factor is sized to accept a variety of cable gauges and winding forms used in antenna matching networks and small transformers. Exact FT-140 dimensions follow industry conventions for that toroid family and the part is sold in a 2-piece set.

Typical uses: These ferrite toroids are commonly employed in EFHW antenna chokes, 9:1 and 1:1 balance-to-unbalance transformers, feedline common-mode suppression, and as cores for small power transformer or inductor builds. They are suitable for industrial automation, communications gear, medical devices and laboratory equipment where RFI containment and signal integrity are priorities.

Installation and handling: The toroidal, slip-over design lets you place cores on cables or wind multiple turns without adhesive or mechanical fastening. Their ring shape simplifies retrofitting to existing wiring runs and makes them straightforward to use in new builds. Handle with care to avoid chipping; while the finish reduces the chance of surface damage, rough handling can cause fragments which may be cosmetic or, rarely, affect function.

VerdictThese FT-140-43 toroidal ferrite cores offer reliable radio-frequency interference suppression for antenna feedlines, baluns, ununs and power transformer windings. Supplied as a pair in the FT-140 form factor, they’re built from a high-permeability ferrite mix suited to broadband EMI/RFI control. They’re simple to fit, durable under typical operating conditions and work well in many industrial and

nerp 1/5

Not suitable for me

No magnetism. No return.

Kenneth Allen Haarsager 5/5

Works as intended

Very happy with them.

Cal C 3/5

Mixed condition across the order

The first two toroids I received were in good condition, but of the next pair one arrived with fairly large chips along the inner bore. Packaging was a plastic box for each core and I didn’t find the fragments inside, so the damage may have occurred before shipping. Despite the cosmetic flaws, the intact pieces work well for building 9:1 UNUNs and 1:1 BALUNs used with amateur radio antennas.

Eagle 5/5

Arrived intact

Arrived intact.

Kaylezin 5/5

Too small for my project

Too small for my needs. Looks fine otherwise.

Dale Moore 5/5

Right size for my needs

Solid ferrite toroid in the right size for me.

marty 5/5

Perfect fit for antennas

Great for antenna builds; arrived quickly.

K 5/5

Lower SWR and less noise

Ideal for baluns and ununs.

FT-140-43 Ferrite Toroid Cores for EFHW & Power Transformers — 2 Pieces

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