RF Choke CK300W Shortwave Common Mode Filter, 1.8-54MHz EMI Suppression RFI Reduction Choke Inductors, 0.2dB Insertion Loss, SWR<1.2, Ferrite Core for Amateur Radio Indoor Use

Specification: GOOZEEZOO 3-in-1 Shortwave Common Mode Filter The GOOZEEZOO 3-in-1 Shortwave Common Mode Filter is a multi-functional RF accessory specially designed for amateur radio bands. It integrates three core functions: common mode filtering, grounded terminal, and band-pass filtering, primarily used to suppress unwanted RF noise, static electricity, and common mode currents on the outer braid of coaxial cables. Common mode currents not only severely disrupt the normal operation of amateur radio equipment but may even cause equipment damage. This choke ring effectively blocks common mode currents from entering the device while fully ensuring the transmission integrity of effective signals on the inner conductor. It is an essential and indispensable component in shortwave antenna systems for improving transmission efficiency, ensuring transmission quality, eliminating static electricity, resolving interference issues, and enabling safe operation. Covering the full shortwave band of 1.8–54 MHz with a standard 50Ω impedance, this filter features a low insertion loss of 0.3 dB at 28 MHz, an SWR <1.2, and common mode attenuation up to 50 dB. The built-in band-pass filter precisely filters out all interference signals outside the 1.8–54 MHz range, reducing radio noise at the source, significantly improving receiving clarity, lowering the noise floor, and minimizing RF feedback, distortion, and inter-equipment interference. The series includes three core models: 2000W, 1000W, and 300W, sharing identical basic RF parameters while differing in power rating, structure, and functional compatibility to precisely match various amateur radio devices and usage scenarios. The 2000W and 1000W models are equipped with waterproof and sun-proof housings, with waterproof connectors, enabling long-term outdoor installation even in harsh environments. The 300W model is a compact common mode filter with only the magnetic ring core, lightweight and simple, ideal for miniaturized and indoor applications. As a high-performance common mode choke balun, its core role is to concentrate RF energy on the antenna and prevent it from leaking back into the feedline or radio room. Its five key functions are summarized as follows: Static Elimination: Effectively dissipates static charges from the antenna, solving strong static issues in dry conditions (e.g., winter) and ensuring equipment and operational safety. Isolation & Decoupling: Provides high electrical isolation between the antenna and feedline, preventing the feedline outer shield from acting as part of the antenna and avoiding interference caused by feedline radiation. Enhanced Radiation Efficiency: By suppressing common mode currents, it forces RF current to follow the designed path directly to the antenna elements, greatly improving the RF radiation efficiency of the antenna. RFI Suppression: Blocks reverse RF signal leakage into the radio room, preventing indoor RF interference and ensuring equipment compatibility and operational safety. Improved Radiation Pattern: Maintains the designed standard radiation pattern for directional shortwave antennas, preserving their directional communication performance.

• 300W Low-Power Use: This EMI Suppression Choke is a cost-effective signal optimizer specifically designed for low-power shortwave transceivers and indoor antenna systems. The 300W power rating perfectly matches the communication needs of entry-level operators seeking signal purity in smaller shacks
• Professional Signal Purity: Covers the full 1.8-54MHz shortwave band with a standard 50Ω impedance for a perfect match with coaxial feedlines. It achieves an ultra-low 0.2dB insertion loss and 50dB common mode attenuation to suppress unwanted noise floor interference
• Ultra-Compact Ferrite Core: Features a lightweight, space-saving ferrite design that can be directly wrapped on 50Ω coaxial cables without the need for extra housing. This RF choke filter fits seamlessly into compact indoor radio setups and crowded desktop equipment areas
• Plug-and-Play Installation: Engineered for simplicity, this filter requires no complex grounding terminals or technical configuration. It installs directly at the transceiver input or indoor antenna feedline to provide immediate RFI suppression
• Enhanced Indoor Reception: Dramatically improves communication clarity by isolating the feedline from the antenna to prevent crosstalk. It suppresses indoor RFI and maintains antenna radiation patterns for stable, interference-free shortwave operation