HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl EM-25 China Mainland

HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz

EM-25 / China Mainland
$75.30 $93.68
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HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl EM-25 China Mainland
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl EM-25 China Mainland
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl EM-25 China Mainland
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
  • HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz HF Choke Coil Ring Axl
HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz

HF Shortwave Choke Coil Ring EM-43 & EM-25 | 1.8–30MHz

$75.30 $93.68
Color
Ships FromChina Mainland

1.8–30MHz Shortwave Choke Coil Ring – EM-43 & EM-25, M Male–M Female Interface

Upgrade your HF shortwave radio setup with this precision-wound shortwave choke coil ring. Designed to suppress common-mode current across the 1.8–30 MHz frequency range, this coil ring dramatically reduces electromagnetic interference (EMI) between your transceiver and feeder line — keeping your signal clean and your station performing at its best.

Available in two configurations: the EM-25 (small ring, 200W) and the EM-43 (large ring, 1000W). The larger EM-43 ring offers superior heat dissipation, making it ideal for high-power HF operations.

Key Features

  • Common-Mode Current Suppression: Effectively reduces EMI, protecting your radio equipment and improving overall signal quality.
  • High-Quality Ferrite Rings: Carefully wound with premium imported ferrite cores — EM-25 and EM-43 material for reliable HF performance.
  • M Male–M Female Interface: Easily connects in series between your radio station and feeder line with no adapters needed.
  • Two Ring Options: EM-43 (large, ~6 cm diameter, 1000W rated) and EM-25 (small, ~4.5 cm diameter, 200W rated) — choose the one that fits your power requirements.
  • Durable ABS Construction: Robust black ABS housing protects the coil winding for long-lasting field use.
  • No Battery Required: Passive device — plug in and start operating immediately.

Specifications

Frequency Range 1.8 – 30 MHz (HF Shortwave)
Interface M Male – M Female (series connection)
Material ABS housing, ferrite core
Color Black
EM-25 (Small Ring) 200W rated, ~4.5 cm ring diameter
EM-43 (Large Ring) 1000W rated, ~6 cm ring diameter
Country of Origin Made in China

What's in the Box

  • 1 × Shortwave Choke Coil Ring (EM-25 or EM-43, as selected)

Notes

  • Monitor color settings may cause slight variations in appearance vs. actual product color.
  • Please allow minor measurement tolerances for stated dimensions.

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Frequently Asked Questions

Q: What is a shortwave choke coil ring used for in an HF radio setup?

A: A shortwave choke coil ring is a passive ferrite-core device placed in series between your HF transceiver and the antenna feeder line. It suppresses common-mode current — unwanted RF current that flows on the outer shield of your coax — which is a major source of electromagnetic interference (EMI). By blocking this common-mode current, the choke coil ring helps improve signal clarity, reduce RF feedback into the shack, and protect connected equipment.

Q: What is the difference between the EM-25 and EM-43 choke coil rings?

A: The EM-25 is a smaller ferrite ring (approx. 4.5 cm diameter) rated for up to 200W — ideal for QRP or low-to-medium power HF stations. The EM-43 is a larger ferrite ring (approx. 6 cm diameter) rated for up to 1000W, offering superior heat dissipation and suited to high-power HF operations. As a general rule, the larger the ferrite ring, the better its thermal performance under sustained high-power use.

Q: What connector type does this choke coil ring use?

A: This choke coil ring uses an M-type (PL-259/SO-239 compatible) Male-to-Female interface, making it straightforward to connect in series between your radio and feeder coaxial cable without any additional adapters in most standard HF radio installations.

Q: Does this device require a power source or batteries?

A: No. This is a fully passive device — it requires no external power source or batteries. Simply connect it inline between your transceiver and antenna feeder to begin benefiting from common-mode current suppression immediately.

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