CMC-154-3K 1-54MHz


Common Mode Filter Choke / Noise Suppressor / Line Isolator

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

  • Multi-Zs™ Technology
  • Covers 1-54MHz
  • Power 3kW *ICAS
  • Common-mode attenuation: ~39dB
  • Choking Impedance 3000-7000 Ohms
SKU: CMC-154-3K Category: Tags: , ,


CMC-154-3K Common Mode Filter Choke / Noise Suppressor / RF  line Isolator


This is the one and only true Common Mode Filter Choke / RF line Isolator for 1-54 MHz on the market. It is the only product with over 7000 Ohms of CMI on 50MHz while maintaining a Resistive part of CMI for more than 50MHz of the frequency spectrum, actually, it has the same values all the way up to 85MHz.

  • Multi-Zs™ Technology
  • Perfect to cure RFI/EMI problems.
  • Great noise suppressor!
  • Common-mode attenuation is up to 39dB max. (measured in 50 Ohms systems)

It is a cure for noisy locations, reduces 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 CMC154-3K 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-154K has huge Resistive values of Common Mode Choking Impedance from 1.8-54MHz, 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-154-3K Common Mode Choking Impedance and its Resistive (Rs) part is always higher than the Reactive part (Xs) over the working bandwidth. This parameter, Rs>Xs ensures 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-154-3K Features:

  • SO-239 PTFE (Teflon®) Connectors which produce no impedance bump but a continuity of coaxial cable where the choke is inserted, it helps minimize leakage of RF in multi/contest stations setups.
  • PTFE (Teflon®) insulated coaxial cable used can handle a lot more than legal power (1500W) in The USA.  It is rated only to 3kW because of the cable limit at the 50MHz.
  • The enclosure is UV stable and could be used outside.

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

Common Mode Impedance data Chart

Frq.(MHz) Zmag(Ohms) Rs(Ohms) Xs(Ohms)
1.85 2500 1200 2200
3.7 3700 2600 2500
7 4800 3800 2800
10.1 5900 5250 2750
14 6500 6300 1700
18.1 6500 6500 700
21 6400 6400 360
24.9 6250 6250 -18
28 6150 6150 -140
50.1 7400 7300 -1100
  • Zmag-Impedance Magnitude     
  • Rs-Series Choking Resistance      
  • Xs-Series Choking Reactance
CMC-154-3K Common Mode Impedance
CMC-154-3K Common Mode Impedance
CMC-154-3K Insertion Loss
CMC-154-3K Insertion Loss

*ICAS = Intermittent Commercial and Amateur Service

Additional information

Weight 25.0 oz
Dimensions 9 × 6 × 2 in
Common-mode attenuation:

~39dB maximum

Frequency Range:

1-54 MHz

Maximum Power:

3kW I.C.A.S


PTFE/silver SO-239 connector with Gold pin


(L x W x H) (in / mm) 10.00 x 2 in. / 254 x 51 mm


1.1 lb (0.49 kg)