1″/25.4mm max Cable Size Chokes
Model BA-200. For use with RG-218 and similar size cables up to 1" OD without connectors installed. Works on all impedance cables, 1.8-300 MHz. Choke outside diameter is 2 inches Requires 9-1/2 inches of cable for 5 bead version, 17" of cable for 10 bead version, and 25" of cable for 15 bead version. Use BA-200-10 or BA-200S-15 for higher choking below 21 MHz. For 10-12 meter frequency use 5 beads up to 15 KW PEP, 10 beads for up to 30 KW PEP and 15 beads for up to 45 KW PEP. We use mix 31 for all chokes. Heat shrink weather proofing kit included. Picture shows 10 bead version.
Rule of thumb suggests you need minimum 5x-10x the coax line impedance for effective choking and the more the better as it will reduce common mode current with higher choking impedance. Select chokes with minimum of 500 ohms at your frequency of interest for best results or upgrade to our CUBE(TM), TUBE(TM), Super Choker(TM) chokes up to 15,000 ohms choking.
Select 10 bead version for 160 meter use, 15 bead version for even higher choking power on lower frequencies. Power rating is same as coax cable used power rating.
Typical choking impedances (BA-58, BA-8, BA-200):
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
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.
 FSB-1/4 – 1 turn |
 FSB-1/2 1 turn |
 FSB-1/2 Open Shell |
 FSB-1/2 2 turns |
 FSB-1/2 3 turns |
 FSB-1/2 4 turns |
—–//—–
More examples of split bead use
Ethernet Cable on FSB-1/4
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
 FSB-1/4 or FSB-1/2 4 turns for 14-50 Mhz 2K-3K Z |
 FSB-1/2-5 turns for 10-30 Mhz 2K-4.5K choking Z |
 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.