Description
FT240-43: The FT240-43 is one of the most popular ferrite toroid’s for HF work. Made from material #43, it provides an excellent balance of broadband impedance and manageable losses across the 3.5–50 MHz range. A top choice for baluns, ununs, and common-mode chokes in amateur radio and EMC designs. Ferrite toroid’s are primarily used as EMC chokes for suppressing RF interference in the MHZ region and in signal transformers. A single FT240-43 ferrite toroid is typically rated for 100W–300W in continuous duty (FT8/CW) or up to 500W–1kW + in PEP (SSB) applications, depending on the SWR and duty cycle. For high-power applications (e.g., \(1\text{kW}+\) or \(400\text{W}\) continuous), stacking two or more cores is standard practice to manage heat and prevent saturation.
What is a Toroid Ferrite Core:
A toroid ferrite core is a magnetic component made from ferrite, a material composed of iron oxide and other metal oxides. Ferrite cores offer excellent magnetic properties and low losses at high frequencies, making them ideal for controlling electromagnetic interference (EMI) and improving signal transmission in radio circuits.
Popular Uses for Ferrite Toroid Cores:
The FT240-43 ferrite toroid core is great for a variety of DIY and home electronics uses:
Building common mode chokes to filter unwanted signals
Creating wideband transformers for antennas (5 – 400 MHz)
Improving RFI suppression in audio, computer, and radio equipment (5 – 500 MHz)
Constructing power transformers for hobbyist radio transmitters (0.5 – 30 MHz)
Perfect for end-fed half-wave (EFHW) antennas and ham radio baluns
Typical Applications:
1:1 and 4:1 baluns for HF antennas (dipoles, OCF, EFHW)
Common-mode chokes for HF coax feedlines
Ununs for vertical and long wire antennas
EMI suppression in HF bands
Specifications:
Frequency Range: 0.5 – 500 MHz (optimal suppression 20-200 MHz)
Material: Mix 43 (NiZn)
Permeability (\(\mu _{i}\)): 800\(A_{L}\)
Value: 1075 \(\pm \) 20% \(nH/T^2\)Outer
Diameter (OD): 2.40 inches / 61.0 mm \(\pm \) 1.30 mm
Inner Diameter (ID): 1.40 inches / 35.55 mm \(\pm \) 0.85 mm
Height: 0.50 inches / 12.7 mm \(\pm \) 0.50 mm
Specific Heat: 0.25 cal/g/°C
Thermal Conductivity: 3.5 – 4.5
Tensile Strength: 4.9 kgf/mm2
Compressive Strength: 42 kgf/mm2
Specific Gravity: ≈4.7 g/cm3
