Slip On Ferrite Beads

Icom IC-7300 Transceiver RFI Kit - 5 Noise Reduction Filters

In stock
Product Details
UPC: Does not apply
Brand: Palomar Engineers
Type: NEW
Country/Region of Manufacture: United States
Filter Power Rating (PEP watts): = Cable Rating
RFI Suppression Range (MHz): 1-300 MHz
# Ferrite Filters: 5
Enclosure Size (inches): n/a
Typical Use:: AC/DC power, RF output, 3 additional I/O lines


This kit will help reduce or eliminate:

1. Radio Frequency Interference (RFI) to electronic devices including audio/video systems, computers, telephones, garage door openers, alarm systems, and home appliances, in your house or your neighbor’s house.

2. RFI from other electronic devices such as switching power supplies, LED and fluorescent lights, battery chargers, Ethernet cables, solar systems, kitchen appliances, and cable/satellite TV systems which generate common mode currents on your radio cables.

3. These filters help cure SWR problems between transceiver and a linear amp and between transceiver and antenna tuner or direct to antenna. The DC power line filter helps keep common mode current out of the power line which could cause interference to other devices connected to the same power source.

These chokes use a ferrite core material that is effective in suppressing RFI from transmitters and receivers experiencing a high noise floor in the 1-300 MHz range.

The ferrite split beads and ring filters are easy to use, don’t require modification of the protected equipment and work in almost all cases, even when plug-in filters fail.

Kit Includes 2 noise reduction ring filters for coax and AC/DC power and 3 snap on filters for I/O cables. Quick installation - immediate RFI/noise reduction. No radio mods required. Snap on ferrites may be either 4 or 6 sided depending on inventory - they have identical electrical properties..

For additional RFI suppression, use a feed line choke at the antenna feed point to suppress common current on the coax feed line during TRANSMIT and a CMNF-500-50 coax noise filter at the radio end of the coax to reduce common mode noise during RECEIVE.

If you use a linear amplifier use a Palomar Engineers amplifier RFI kit for additional RFI interference suppression.

We stock RFI/Noise Reduction kits for most brands of radio transceivers and generic kits for others

Visit our website for all your RFI/noise reduction needs!

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Ferrite beads are used for RF decoupling and parasitic suppression. When placed over a wire, cable or coaxial cable they suppresses common mode current flowing on the wire or wire bundle or the outside of the coax shield but does not affect the signal inside the coax cable or wire (differential current).

For RFI common mode suppression use, mix 31 is effective from 1-300 Mhz, mix 43 works from 25-300 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-50 MHz.  These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected.  See Mix Selection for other applications.


Bead dimensions are shown in the picture below and in the table as A, B, C

Core Sizes - Slip On Ferrite Beads

Ferrite Bead Dimensions


Application Note:  Use impedances for each bead at your desired frequency to select number of beads needed for desired Z.   For example if you have a 50 ohm RG-8 coax cable and want a choking impedance of 500 ohms at 10 Mhz, you can check the FB102 column (since FB102 will pass RG-8 through its center ID) at 10Mhz and find that Mix 31 has a Z of  108 ohms/bead and Mix 43 has a Z of 91 ohms/bead.  For 500 ohms we would need 5 mix 31 beads or 6 mix 43 beads to have greater than 500 ohms.  Mix 31 has better response below 10 Mhz but above 10 Mhz mix 31 and mix 43 are very close.  If you need more Z, just use more beads in series on the cable or use more windings thru a larger ID bead (e.g. USE FB102-31 for 4 turns of RG-8X for 16X increase in Z per bead – see pictures below for examples).  Use Mix 61 for VHF and above for RFI/EMI suppression and below 30 Mhz for multi-ratio impedance transformers (baluns/ununs).  See Mix Selection for other applications.

For extra large cables use the FB400-31 which has an inside diameter of 3 inches (76mm).

Frequency Range Comparison Chart

(FB56-xx size)

FB56 xx bead mix comparison - Slip On Ferrite Beads

Multi-turn Common Mode Choking Impedance Increase Example (FB56-43)

FB56 43 Turns Impedance Graph - Slip On Ferrite Beads

Ferrite Bead relative size comparison

FB56 FB102 FB103 Relative Sizes - Slip On Ferrite Beads

Left to right sizes: FB56 (ID = .25″), FB102 (ID=.505″), FB103 (ID=.77″)

Application note for using Slip On or Snap On ferrite beads for RFI/EMI suppression: How many chokes do I need?

SLIP ON Sizes for Heliax and Coax Cable

Shown below in the table are the SLIP ON and SNAP ON products for various popular Heliax and Coax cables.  These are the correct size for making sleeve baluns.
SNAP per Coax - Slip On Ferrite Beads

Cascaded Common Mode Chokes/Line Isolators/1:1 Baluns

Here is a simple idea that is cost effective and simple to make using FB102-31 ferrite beads with RG-58 (1/4″) size cable.  Take a FB102-31 bead and insert 4 turns of RG58 spreading them out 360 degrees to minimize the capacity effects.  4 turns give 16X the choking impedance of a single bead.  So let say you are having a problem with 7 Mhz interference.  Typcial choking impedance at 7Mhz for the FB102-31 per the chart above is around 70 ohms for a single turn through the center of the bead.  With 4 turns we have 16 x 70 = 1120 ohms and with two chokes on the cable in series we would have 2240 ohms which is pretty good for $11 in beads.  See picture below for example of how these beads are used.  This winding technique is also applicable to FSB-1/2 Snap On Ferrite Split beads which will accommodate 3 turns of RG-58 coax which already has a connector attached.
Need even more choking impedance?  Use a larger diameter toroid like a FT240-43 (best above 10 Mhz) or 31 mix(best below 10 Mhz) and put 12-14 turns of RG58 on the toroid as shown below.  Our Super Choker is very similar to the toroid choke example shown below but uses multiple FT240 toroids and is useful for larger 1/2″ size cable like the RG-213, RG-8, etc.  You can order the FB102 beads and the FT-240-31 from info on this page and the FT-240-43 on the Ferrite Toroid Cores page.
RG-58 Multi-Turn Chokes/Line Isolators Examples

20131222 124620 300x180 - Slip On Ferrite Beads

RG58 4 turns on 2 FB102-31 for 2000 ohms choking impedance

20131222 125533 300x180 - Slip On Ferrite Beads

RG58 12 turns on FT240-43 for 4000-6000 ohms choking impedance

Got a question about using ferrites?  Drop us an email at  and we will be glad to answer your question.

Handy Wire Size reference for ferrite bead sizes needed

 wire guage chart2 - Slip On Ferrite Beads


Connector already on cable?  See Snap On Ferrite Beads for convenient installation on cables with connector already installed.