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Ferrite marking pens
 

If you own an antenna fed with coax, you need RF chokes on the feedline!  Using a balun with adequate RF choking impedance will improve the performance of your antenna, prevent pattern distortion, and prevent RF coming down the feedline, which can cause RFI.  Many balun manufacturers either don’t make baluns with enough choking impedance, or are overcharging for a product that can easily be made by the ham (and much more effective!). 


Ferrite is a ceramic consisting of iron and metal oxides having high permeability.  When a conductor is passed through the center of a ferrite bead, the impedance goes up with the SQUARE of the number of passes through the center.  To achieve the same amount of choking impedance of a toroid with a few turns through the center, a “string of beads” choke can require 30, 40, 50 or more beads!  Ferrite is made in different formulas, called mixes.  The mix used will determine the best choking impedance for the desired frequency range.  Mixes 31 and 43 are best for HF use (31 is better for the low bands, with mix 43 having a slight advantage from 14 to 30 MHz).  I currently stock mix 31, 43, 61, 77, and 73 ferrite.  Let me know if you are looking for something in particular.  Chris at KF7P dot com.


Check out our TECH page for lots of information on ferrite material and how to properly use it.   Below:   Comparison photo shows the ferrite we stock to use a a size reference.




NEW!  View our new introductory video to ferrite!                                


 

Time to reduce the noise in your shack!  Most baluns that come with antennas these days do not provide enough choking impedance. Replace that ineffective balun that came with your antenna, or add an Excellent Choke where your coax comes in the building. The Excellent Choke has over 4000 ohms of choking impedance at 14 MHz!  Every HF installation should have a high impedance choke on all cables leaving the tower and at the building entrance.  W1HIS’s Excellent Choke is an affordable solution. Avoid paying higher prices by sourcing materials from different vendors and paying multiple shipping charges. Get all the parts from one source!


  1. High performance, high choking impedance stops common mode on coax shield.

  2. Reduce RF in the shack problems (hot mic, feedback, etc.).

  3. Eliminate RFI issues around your house (TV, radio, computer, stereo, etc.).

  4. Lower your receive noise floor.

  5. Can be used at feedpoint of your antenna (replacing balun that came with your antenna), AND/OR at output of radio gear.

  6. RG 142 coax: Teflon dielectric, silver plated copper clad steel conductor, and TWO silver plated braid shields.

  7. Suitable for legal limit RF levels.


Kit includes four Mix 31 ferrite beads, 4 feet of Mil Spec RG 142 coax, and two silver plated teflon PL259 connectors and reducer bushings.  Requires soldering PL259‘s onto the cable; comes with winding instructions.                                                    

W1HIS “Excellent choke!” kit

Ferrite Products for RF Chokes, Baluns, and RFI Mitigation

Useful baluns and chokes for coax.  Large opening allows several passes through center without taking connectors off.  Often a stack of several of these are needed to achieve target impedance.  Specify quantity after adding to cart.

Useful for small cables or one pass with RG8 size coax (mix 43 and 31 only).  Specify quantity after adding to cart.                                                       

Click on chart to enlarge

NEW!!   

Choke is approx. 20” long.

I put one of these excellent choke kits at my transceiver and another "pretty good" choke at the feedpoint of my G5RV Jr. It knocked a good 2 or 3 s-units off of the "band noise" I was experiencing. The product is well made and easy to put together, and the ferrite components are top-notch. I will be ordering more.

WK2X

User Reviews:  What are other hams saying about these products?

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               FERRITE & CHOKES
User Reviews:  What are other hams saying about these products?
Ferrite beads
Ferrite toroids

Love the big mix 31 Ferrite Beads...They really do the trick.

KE7IHG

*****

*****

Made on a Mac

Love Big Mix 31 works great !! Made a big difference on my transceiver.

KC3EDV

*****

*****

Electrical tape







Liquid electrical tape

Related Accessories

Zip ties

Price:

$38.95

Purchased the "Biggest Clamp-On" 220-31 for common mode rejection.  Both the price and service were excellent; Very competitive. 

W3FRG

*****

*****

Models Available:


Excellent choke, kit form

olights

For easy assembly without taking connectors off or disconnecting cables.  “Biggest Clamp On” is roughly equivalent to three toroids above, and easier to use.   This is a monster ferrite!  Specify quantity after adding to cart.

Models Available:      


Small clamp-on, mix 43

Dimensions:

Length      1.25”

OD           .875”

ID             .400”


Price:  $2.95


Small clamp-on, mix 31

Dimensions:

Length    1.55”

OD          1.22”

ID             .512”


Price:  $4.95

Ferrite clamp-on’s

Medium clamp-on, mix 31    

Dimensions:

Length     1.87”

OD            1.52”

ID              .722”


Price:  $8.95




Biggest clamp-on, mix 31    

Dimensions:

Length   1.69”

OD          2.2”

ID            1.0


Price:  $14.95


Models Available:      

Ferrite toroid,  mix 43

Dimensions:

Length     0.5”

OD            2.4”

ID              1.4”


Price:  $5.50



Ferrite toroid, mix 31

Dimensions:

Length     0.5”

OD            2.4”

ID              1.4”


Price:  $7.95




MONSTER toroid, mix 31

Dimensions:

Length      1”

OD            4”

ID              3”


Price:  $19.95

    


Ferrite toroid,  mix 61

Dimensions:

Length     0.5”

OD            2.4”

ID              1.4”


Price:  $8.50



Ferrite toroid, mix 77

Dimensions:

Length     0.5”

OD            2.4”

ID              1.4”


Price:  $7.95

click for larger version


Models Available:     

Ferrite bead,  mix 43

Dimensions:

Length    1.125”

OD           1.020”

ID             0.505”



Price:  $2.95



Ferrite bead,  mix 73

Dimensions:

Length    0.38”

OD           0.190”

ID             0.197”



Price:  $0.15

Note:  This is one tiny ferrite bead, only fits over RG58, RG174, or  RG303.  At least 50 beads are needed to provide an acceptable level of choking impedance.






Ferrite bead, mix 31

Dimensions:

Length    1.125”

OD           1.020”

ID             0.505”




Price:  $3.45

MONSTER toroid great for choking large cables with connectors that cannot be removed.

Picked up an excellent choke kit for the feedline and biggest clamp on for the power cable.  They work great, shipped fast, Thanks!

KN2X

*****

*****

These mix 31 snap on beads that Chris sells are the best.  He packs them up well and shipping is fast!  The largest Mix 31 snap on bead can fit 4 turns of LMR400 Flex through it no problem.  Perfect for getting rid of my 10 meter common mode interference.  Prices are also better than all of the other suppliers I checked.

VA3HD

*****

*****

I bought 4 of the mix 31 beads to make the W1HIS “excellent choke”.  If you lube the coax slightly you can get 3 turns of RG8X through these

.505” beads.  I was shocked at how much this arrangement reduced the noise floor in my receiver...6dB or more on 40 meters.  I’ll be ordering more to experiment with.  KF7P does an excellent job of packing and ships very quickly,..highly recommended.

KX4IK

*****

*****

I have successfully stopped all RFI from my shack with these snap on chokes.  They are the best I’ve seen, and Chris has the best prices I’ve found on these essential parts for the shack.  Plus great packing and fast shipping.  Highly recommended.

W5DGM

*****

*****



Ferrite bead,  mix 61

Dimensions:

Length    1.125”

OD           1.020”

ID             0.505”



Price:  $4.75

Ferrite bead, small, mix 61

Dimensions:

Length     1.125”

OD           0.562”

ID             0.25”


Fits small coax: RG58, RG8x, RG400, RG142, etc.


Price:  $1.75



Small clamp-on, mix 61

Dimensions:

Length    1.55”

OD          1.22”

ID             .512”


Price:  $4.95

Customize your ferrite for easy identification with our new marking pens below!

Customize your ferrite for easy identification with our marking pens!  Ferrite comes in different formulas or “mixes”, and it is almost impossible to tell different mixes apart.  Be sure to get some of these inexpensive marking pens and customize your ferrite so you know which type to use.  White can be used as a base  for writing on with black (or other colors), or a color code chart can be used in a way similar to resistor color codes.  12 colors available.

click for larger version


OUT OF STOCK