The Diamond CMF-2000B is a highly effective, professional-grade common-mode choke filter and line isolator engineered to resolve challenging Electromagnetic Interference (EMI), RF feedback, and Television Interference (TVI) in your station setup. Developed by the RF specialists at Diamond Antenna, this heavy-duty filter prevents stray RF currents from traveling back down the outer shield of your coaxial transmission cable—a common cause of distorted audio, computer lock-ups, and interference with surrounding household electronics.
Operating seamlessly across a broad frequency spectrum from 1 to 54 MHz, the CMF-2000B provides complete protection for the HF amateur bands, CB radio (27 MHz), and the 6-meter (50 MHz) band. It serves a dual purpose as an RF choke line isolator and low-pass filter, effectively eliminating unwanted harmonic frequencies outside the core 1-54 MHz operating range. Designed to support high-power stations, it handles up to 2 kW PEP (Peak Envelope Power). It connects inline using standard female UHF (SO-239 / MJ) connectors.
The internal architecture of the CMF-2000B is optimized for minimal insertion loss, keeping it under 0.3 dB. It exhibits an incredibly low Standing Wave Ratio (SWR) of less than 1.2:1 to protect your transceiver’s power amplifier. Common-mode signal currents are heavily attenuated, achieving an attenuation level greater than -30 dB. Housed in a durable, weather-insulated cylindrical shell measuring 380 mm in length and weighing 610 g, this filter is built for years of reliable, maintenance-free service.
Key Features
- Common-Mode Interference Prevention: Effectively isolates and blocks stray RF current on the coaxial cable shield, eliminating TVI and EMI/CEM issues.
- Broad 1–54 MHz Range: Perfect for HF amateurs, CB operators (27 MHz), and the 6m (50 MHz) band.
- High Power Handling: Capable of handling up to 2 kW PEP, making it ideal for high-power linear amplifiers.
- Superior Attenuation: Delivers common-mode attenuation greater than -30 dB.
- Ultra-Low Insertion Loss: Under 0.3 dB of loss preserves your transmitter’s signal strength.
- Rugged Housing with SO-239 Connectors: Fitted with durable MJ (UHF Female / SO-239) connectors for easy transmission line installation.
Technical Specifications
| Parameter | Specification |
|---|---|
| Brand | Diamond Antenna |
| Model Designation | CMF-2000B |
| Product Type | Common-Mode Choke & Line Isolator |
| Frequency Coverage | 1 – 54 MHz |
| Maximum Power Rating | 2 kW PEP (2000W) |
| Common-Mode Attenuation | Greater than –30 dB (max.) |
| Insertion Loss | Less than 0.3 dB |
| SWR (Standing Wave Ratio) | Less than 1.2 |
| Nominal Impedance | 50 Ohms |
| Connector Type | UHF Female (MJ / SO-239) |
| Physical Length | 380 mm (including connectors) |
| Net Weight | 610 g |
Package Content
- 1x Diamond CMF-2000B Antenna Filter / Line Isolator
- 1x Quick Start Mounting Guide
