Coax Feed Line Common Mode Chokes (1:1)

Coax Common Mode Chokes

Common Mode Current (CMC) carried on the outside of a coaxial cable braid from your antenna can cause unwanted RF in your radio shack and can radiate this unwanted RF into you and your neighbor’s electronic devices.  These currents can burn your fingers on the key or lips on your microphone and they can cause computers and other devices to fault or stop working when you transmit.  To reduce CMC on the coax you can use Coax Common Mode Chokes.  These chokes come in many varieties for various frequency ranges, mechanical attachment methods, choking impedance and cable size.  Palomar Engineers offers five choices including Sleeve Chokes, Super Choker™, CUBE™ Chokes, TUBE™ Chokes and Tuned Coaxial Chokes in a range of choking impedances and shapes for small and large cable sizes and various antenna types.

Need help in choosing a common mode choke for your application?  Read: Choosing a Feed Line Choke

Click on the links or pictures for more info on specific feed line chokes.

SLIP ON SLEEVE CHOKES (Kit and Assembled)

BA-8 on RG-213 Cable - SLIP ON Baluns for 1/4", 1/2", 3/4", 1", 1.4", 3" cable

BA-8 on RG-213 Cable – SLIP ON Baluns for 1/4″, 1/2″, 3/4″, 1″, 1.4″, 3″ cable


Coax Common Mode Choke

SNAP ON Kit 105 Installed on RG-58 Cable – SNAP On Sizes 1/4″ up to 1″ cable




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feed line chokes for beams, dipoles and verticals

Many customers have requested an assembled sleeve unun or balun for 1/2? size cable and we have one all completed with shrink tubing and PL-259 end connectors or open ended on one end for a balanced connection such as a beam, dipole, etc.  Available in 5, 10 and 15 bead version for increased low frequency choking.



Sometimes you need a common mode choke that is simple to install and super effective and the Super Choker™ is our solution for installations requiring high power, high SWR, high choking, and low saturation loss.  Three models optimized for maximum common mode choking on the 160-40 meter bands, 40-10 meters or 80-10 meters.  Click here to learn about this great choke.

Super Choker Coax Common Mode Choke



Current Unun and Balun Enclosure – CUBE Baluns™ are ferrite toroid common mode chokes/1:1 baluns/ununs  available in weatherproof enclosures with various input and output connectors.  CUBE baluns give higher choking impedance than other choke types due to a larger number of turns .

Enclosure Box U1Unun Style 1 Enclosure Box B2Balun Style 1 Enclosure Box B1Balun Style 2










TUBE feed line chokes are convenient for insertion in the coax feed line at the antenna feed point or the station entrance and they include an optional  ground lug and static bleeder for attachment to a ground rod.  Very useful as coax line isolators along a long coax feed line to break up resonances every 1/2 wavelength. Very wide bandwidth, high choking resistance for 1-161 MHz use. Click on picture below or HERE for more info.

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Palomar Engineers Maxi-Choker Coax Feed Line Choke Unun for 1-161 MHz



TUNED COAXIAL CHOKES are excellent for high power, high duty cycle single or adjacent band operation (Typical 5-10 MHZ bandwidth).  They are convenient for insertion in the coax feed line at the antenna feed point, at 1/2 wavelength intervals in long coax lines to break up resonances or at the station entrance.

Coax Common Mode Choke

Got a question about using feed line chokes?  Check out our Application Notes page for more info on RFI and using common mode chokes.

Still need Help? Drop us an email at  and we will be glad to answer your question.