Snap On Split Beads

RFI Solution Kits

Palomar Engineers provides a variety of Radio Frequency Interference (RFI) and Electro-Magnetic Interference (EMI) solutions from 100 KHz to 1000 MHz.

We have many RFI solution kits targeting common RFI problems encountered by consumers, broadcast professionals, radio operators, industrial plant managers, marine/ship operators, solar power contractors, etc. For custom individual RFI problems we offer individual ferrite RFI suppression components in bead, snap on and ring topology to fit various wire/cable configurations for AC/DC power cables, coaxial feed line, and device interconnect cables.

Different ferrite mixes suppress different frequency ranges. To select a mix for your interfering frequency see: Choosing a Ferrite Mix

To learn about using ferrites for RFI/EMI suppression check out : RFI Tutorial Center

Get a Copy of Ham Radio RFI Cheet Sheet for all your communication RFI issues!

If you need additional help call 760-747-3343 or email Sales@Palomar-Engineers.com describing your problem.

Often it is difficult to slip beads on a cable because of a plug or connector. Split beads solve this problem. They come in two halves that fit over the cable. A plastic snap cover holds the two halves together and holds the assembly on the cable.

For RFI use, mix 31 is effective from 1-300 Mhz, mix 43 works from 20-250 Mhz, Mix 61 is for 200-2000 Mhz, and mix 77 favors .1-20 MHz. These frequencies are those of the interfering signal to be eliminated, not the operating frequencies of the equipment to be protected.

Not sure of what sizes you need or solving a RFI problem with devices using multiple size cables?  Try the Ferrite Snap On Combo Pack which has sizes from 1/4″ to 3/4″ with either Mix 31 (1-300 MHz) or Mix 61 (200-2000 MHz) or Mix 75 (150 KHz – 10 MHz).

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

FAIR RITE 185M CLIP ON FERRITE BEAD SPLIT CORE - Snap On Split Beads

Ferrite Split Bead Dimensions

Application Notes

Application Note for using these Snap On split beads: How Many Chokes do I need?

You can very effectively increase the choking impedance of smaller cable by using a large hole ferrite bead and wrapping the cable through several times.  For particularly difficult common mode current/RFI problems you may need a choking impedance as high as 5-10K ohms.  Using multiple beads and multiple turns through each bead will give higher impedances up to a point.  At higher frequencies, when the number of turns approaches an electrical wavelength, the choke becomes resonant due to stray capacitance and the inductance of the cable and limits the high end impedance values to less than the above table points.

Some example of ways to wrap cable are shown below.

Ferrite Split Beads with multiple turns of RG-58/59

FSB14 1 150x150 - Snap On Split Beads

FSB-1/4 – 1 turn

FSB 12 1 150x150 - Snap On Split Beads

FSB-1/2 1 turn

FSB12 1 Open 150x150 - Snap On Split Beads

FSB-1/2 Open Shell

FSB 12 2 150x150 - Snap On Split Beads

FSB-1/2 2 turns

FSB 12 3 150x150 - Snap On Split Beads

FSB-1/2 3 turns

FSB12 4 150x150 - Snap On Split Beads

FSB-1/2 4 turns

—–//—–

More examples of split bead use

20131210 1148191 300x180 - Snap On Split Beads

Ethernet Cable on FSB-1/4

20131210 114800 300x180 - Snap On Split Beads

Ethernet Cable on FSB-1/2 – 3 turns for 9X Impedance good filter for 15-30 mhz between 2K-3K ohms choking Z

Three Effective Radio Interference Filters

Effective RFI/EMI Chokes

20131219 110956 150x150 - Snap On Split Beads

FSB-1/4 or FSB-1/2 4 turns for 14-50 Mhz 2K-3K Z

20131219 111243 150x150 - Snap On Split Beads

FSB-1/2-5 turns for 10-30 Mhz 2K-4.5K choking Z

20131219 105947 150x150 - Snap On Split Beads

FT240-43 – 14 turns for 3-14 Mhz or use two FT240-43 for 1.8-10 Mhz

These snap-on chokes are useful for reducing RFI in public address system amplifiers, speaker wires, mic cables, mixer panels, coax cable, telephone wires, computer sound card speakers, dsl/cable connections, remote control heads for ham transceivers (Especially FT-100, FT900, IC-706, IC-7000), AC power cables, DC power cables, home theater cables, video cables, HI Fi cables, guitar amps, linear amp cables, etc.

 

They are also helpful in suppressing common mode noise/RFI in radio and TV receivers, audio and RF amplifiers.  They can also help suppress noise generated by treadmills, exercise equipment, fish tank heaters, oil heater pumps, fluorescent lights, motors, cable modems, DSL modems, computers, and many other electrical devices.  Common mode current reduction in computer cables often helps speed up computers.