CMC-130-3K 1-30MHz

(10 customer reviews)


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 1-30MHz
  • Power 3kW *ICAS
  • Common-mode attenuation: ~41dB
  • Choking Impedance 7,000-15,000 Ohms
SKU: CMC-130-3K Category: Tags: , ,


CMC-130-3K Common Mode Filter Choke / Noise Suppressor / RF Isolator

This is the one and only Common Mode Filter Choke for 1-30 MHz on the market.  It is the only product with over 10,000 Ohms of CMI (Common Mode Impedance) on 3.8-30MHz while maintaining a Resistive part of CMI for more than 25MHz of the frequency spectrum.

  • Based on Multi-Zs™ Technology
  • Perfect to cure RFI/EMI problems.
  • Great noise suppressor!
  • Common-mode attenuation is up to ~41dB max. (measured in 50 Ohms systems)
Use it as BALUN for G5RV/ZS6BKJW, Dipoles etc.
Use it as BALUN for G5RV/ZS6BKW, Dipoles, etc. NOTE! PL-259-PL259 adapter is NOT included.

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 CMC130-3K 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-130K has huge Resistive values of Common Mode Choking Impedance from 1.8-30MHz, 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-130-3K 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-130-3K Features:

  • SO-239 PTFE (Teflon®) Connectors which produce no impedance bump but the continuity of coaxial cable where the choke is inserted, 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 up to 3kW in the HF band.
  • The Enclosure is UV stable and could be used outside.
  • Multi-Zs™ Technology
Frq.(MHz) Zmag(Ohms) Rs(Ohms) Xs(Ohms)
1.9 7300 4450 5700
3.8 9900 7500 6300
7.15 14000 13400 4200
10.1 14300 14200 1600
14 13800 13800 -800
18.1 13500 13400 -1600
21.2 13900 13700 -2200
24.9 14500 14100 -3300
28.5 15200 14400 -5000
  • Zmag-Impedance Magnitude     
  • Rs-Series Choking Resistance      
  • Xs-Series Choking Reactance


Common Mode Choke
Common Mode Choke

*ICAS = Intermittent Commercial and Amateur Service

Additional information

Weight 20 oz
Dimensions 11 × 2 × 2 in
Common-mode attenuation:

~41dB maximum

Frequency Range:

1-30 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)

10 reviews for CMC-130-3K 1-30MHz

  1. Mike N4EPD (verified owner)

    After trying your CMC-330-1k common mode choke on my KLM KT34A beam, I realized a 3db reduction in noise and decided to try your CMC-130-3K on my all band windom. It reduced my noise level from S7 to S3. I can’t tell how satisfied I am with the quality of your products and the results. Thanks

    Mike, N4EPD

  2. Bob Moss W1RAM (verified owner)

    Review for the MyAntenna CMC-130-3K September 2016

    I had been plagued by significant RFI noise coming from somewhere in my neighborhood. It got to the point that this “white noise” reached as much as S-8 on 80M and S9+5 on 160, rendering those bands basically useless 24/7. On 40, the noise was often S-6-7 making only the strongest stations being readable. The signal to noise ratio on these three bands was horrible. The utility companies came several times to try to identify the noise source(s) but never with any success. I next tried a Brand X 160-10M Line Isolator and that did nothing. Soon afterward, I saw an ad for the MyAntenna Common Mode Choke CMC-130-3K and decided to give it a try. To my amazement it lowered my noise by 4-5 S-units on 40, 3-4 S-units on 80 and 2-3 S-units on 160. Suddenly, most signals were no longer covered up by the noise. In an instant I could use 160-40M again! So, I decided to get another CMC-130-3K to run in series with the first, one at the end of the 100 ft. coax where it enters my house and the other at the rig’s end. Wow! Now the noise was lowered an additional 1 to 2.5 S-units on these three bands. There was no attenuation of signals that I could detect. While I don’t completely understand how this choke works, I really wish I had discovered it much earlier. Think of all the time I could have saved by not having to walk around the neighborhood with an SW receiver frustratingly snooping for noise. Danny’s Common Mode Choke (CMC) really worked in my case. Instead of hearing mostly noise, now the bands have come alive with signals hidden by that noise. FYI, it did not eliminate other RFI generated by my power supplies and electronic devices, my LG washing machine being the biggest “birdie generator” in my house when in use. But for anyone who has an RFI noise problem similar to mine, I would strongly recommend a CMC from MyAntenna. Danny is super helpful and has always answered my emails with uncommon speed. And when I asked to have the order shipped quickly over Memorial Day weekend, MyAntennas did exactly that! My CMC-130-3K’s gave me three bands back and eliminated a nagging noise problem that I had spent countless hours trying to solve. What’s more, this choke might just be the best “bang for the buck” investment I have ever made in 50+ years of ham radio.

    Bob W1RAM

  3. Derwin KC8KQY (verified owner)

    Ok My QTH has power lines along the back property line that feeds the whole street past my house. On the side property line they run to the street that’s north and the one south of me. Just one house over is the BIG boys on steel poles from one sub station to another. SO 40 and 80 had a horrible noise floor. I run a 10 – 80 OFC with a 4:1 balun due to the 100×150 foot lot I have.
    WOW..!!! S9 noise floor on 80 dropped to S5 just by putting this in the coax right before entering the shack!!!
    40 meters dropped by 3 S Units. 20 meters is also so much better!

    Another Ham wrote : ” What’s more, this choke might just be the best “bang for the buck” investment I have ever made in 50+ years of ham radio.”
    I have not been a Ham 50 years. BUT Quite simply I CAN NOT AGREE MORE….
    I will make note this is not a cure all for all noise. THE STINKING 60 inch Plasma TV in my living room. (THAT I HAD TO HAVE..!! SMH) STILL adds 3 to 5 s units to HF noise floor Depending on band when it is turned on.

  4. A. Bruce K4HK (verified owner)

    Another satisfied CMC-130-3K purchaser here. As others have noted, they don’t eliminate RFI from “wall-warts” and my PC’s VGA cables, but they do attenuate even those common mode noises significantly – from S7 to S1-2 on 20M and S1 on 15 & 10M. The power line noise which was S9 +20 on 80M and S7 on 40M through 10M was reduced to S7, S2-3 and S1 on 80, 40 & 10-20 respectively using 2 CMC-130-3Ks in each coax feedline, one at the antenna switch in the shack and the other at the antenna feedpoint. Also I want to commend Danny for standing behind his products 110% and providing exemplary customer service.

  5. David HC5DX

    I have the CMC-130-3K and it’s a great product. Excellent workmanship as with all his other chokes, Baluns and antenna transformers.


  6. Mike (verified owner)

    Finally a high quality product that works and does not break the bank. Glad to see someone with good business sense, high construction, and good design. Brought my static noise level down by 2 S units. Much heavier than any other RF isolator I have seen or purchased. This is important!!

  7. NEIL MARTIN KS4KY (verified owner)

    This really cleared up a lot of noise for me. Thank you. KS4KY

  8. Art (verified owner)

    Wow! Just received the CMC-130-3K in the mail! Put it in-line to the transmitter and I’m totally blown away!! Nose level dropped off from a constant S5-S7 to less than S2 on 20 meters!!
    Really able to hear those signals formerly buried in the noise!! Great job!!

  9. Chris (verified owner)

    I have 5 of these CMC chokes rigged for 2 antennas. I install them at the antenna feed point and then just before amplifier antenna ports. Also in between the radio and amp. Do this with proper grounding just outside the shack and you have the best setup possible. I have a EFHW with 49/1 UNUN and then this CMC at the feed point. I dont want my 1/2 hardline as a radiator. My counterpoise is wire at 1/4 wave and is perfect. Second antenna is a 43ft vertical. same thing, one at the feed point, another just after the amp. 2 antennas, 5 chokes plus cable gounds and bonded. All RFI is gone, legal limit is perfect, noise level on RX is lowest possible. Verified CMC ratings and are legit. Built well, weather proof…Solid. Chris, AB7BS

  10. Dave

    I have one on my 80-10m 2K. I located it about 50 from the feed point of the antenna and just after my lightening arrestor where the feedline enters the shack. Took 2-3 S-units of noise off my signal. 4 stars due to the price, but I still bought it and would again.

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