CMC-330-1K-CMI Common Mode ImpedanceCMC-330-1K Common Mode Choke / Line IsolatorIMG_20150806_125622CMC-330-1K-web6



Out of stock

5 out of 5 based on 3 customer ratings
(3 customer reviews)

Product Description

Common Mode Choke / Noise Suppressor / Line Isolator

The common-mode filter or choke may be one of the best-kept secrets…

  • Covers 3-30MHz
  • Power 1kW *ICAS
  • Choking Impedance 7000-9000 Ohms

CMC-330-1K Common Mode Choke / Noise Suppressor / Line Isolator

This is Common Mode Choke – CMC or RF Isolator for use with amplifiers up to 1000W *ICAS output. Great to use after amplifiers such as ACOM 1000, 1010, Kenwood TL922, Heathkit SB200, SB220, Ameritron AL572, AL80, AL811 etc. Perfect to cure RFI/EMI problems. Great noise suppressor! It is a cure for noisy locations, reduce the noise floor of your receiver by several S-units instantly.  If you have unbalanced antennas such as OCF dipole or your antennas close to your home, adding one CMC-330-1K will greatly reduce RF Interference problems on your equipment and 120/220V wiring inside your home. We do not claim “one size fits all” but actually, we design, measure and make such products. Our CMC-330-1K has huge Resistive values of Common Mode Choking Impedance from 3 -30MHz or almost whole HF spectrum, click the chart on the side for actual measurement data. Unlike other companies, we do not claim unrealistic impedance values or frequency coverage. Most important, the value of CMC-330-1K Common Mode Choking Impedance and its Resistive (Rs) part is always higher than Reactive part (Xs) over the working bandwidth. This parameter, Rs>Xs ensure that our CMC will NOT increase common mode currents as could with inferior coaxial cable chokes.

Only chokes with Resistive (Rs>Xs) CMI- Common Mode Impedance stops and dissipate unwanted RF or noise coming to your equipment for sure.

See the video of CMC’s in action at AC0HF station

CMC-330-1K Features:

  • Cascaded chokes for maximum Choking Impedance and frequency coverage.
  • SO-239 PTFE (Teflon®) Connectors
  • RG-316  PTFE (Teflon®) insulated coaxial cable used, can handle a lot more power than 1oooW (3kW on 3.5MHz)
    Use it as BALUN for G5RV/ZS6BKW, Dipoles etc.

    Use it as BALUN for G5RV/ZS6BKW, Dipoles etc.


Frq.(MHz) Zmag(Ohms) Rs(Ohms) Xs(Ohms)
3.0 6600 4700 4500
3.75 7300 6000 4200
7.0 8500 8350 1700
10.1 8300 8285 -380
14.15 7500 7400 -1100
18.1 7500 7400 -1100
21.2 7900 7750 -1500
24.9 8400 8000 -2450
28.0 8800 7900 -3400
  • Zmag-Impedance Magnitude     
  • Rs-Series Choking Resistance      
  • Xs-Series Choking Reactance
CMC-330-1K-CMI Common Mode Impedance

CMC-330-1K-CMI Common Mode Impedance

*ICAS = Intermittent Commercial and Amateur Service

Additional Information

SKU: CMC-330-1K Category:

3 reviews for CMC-330-1K

  1. 5 out of 5


    One of my antennas is a center-fed doublet, using ladder line to the T tuner. I placed Danny’s CMC right at the transceiver input/output. It did, in fact, reduce my noise floor. And, at a fair price.

    If you need more choking, look at his other models.

    John W4II

  2. 5 out of 5


    Purchased this item after reading the advertisement, Installed and Yes , It reduced my noise floor by 2-3 S Units. Will be purchasing more for my future installation. Great product and well made. Thanks for offering these! 73 !

  3. 5 out of 5


    I purchased this item after a good conversation with Danny. I currently run a multi-rig station with a Yaesu FT-840, Yaesu FT-101-DZ, Kenwood 430, and a Yaesu 857 with a Ameritron 811-H (for some bump). One of my antennas is Danny’s 8010 (which is AWESOME) but my noise floor was 5 to 6. I put the CMC-330 at the feedpoint of the 8010 per Danny’s instructions. After getting the 8010 back up (30+ft) my noise floor was 2 to 4!!! Africa was coming in like they were just a 2 state hop away!! Great job again Danny!!! 73 de KK4JHL

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