Model SLO-3/4 family of chokes are for use with 3/4” coax cable like LMR600 and similar cables up to 3/4" diameter – works on all cable impedances (50, 62, 75, 90 ohms etc). 80-6 meters.Choose SLO31-3/4-5 (5 beads) or for extended choking, choose SLO31-3/4-10 (10 beads) or for super extended choking choose SLO31-1/2-15 (15 beads). Each additional 5 beads is approximately 6 dB of common mode rejection (also 1 “S” unit of noise reduction). Select chokes with minimum of 500 ohms at your frequency of interest for best results or upgrade to our CUBE(TM), or MC-1-3000 Maxi-Choker(TM) chokes for higher common mode noise rejection.. Select 5 bead version for 80-2 meters use; 10 bead version for 160-6 meter use, 15 and 20 bead version for even higher choking power on 160-20 meter frequencies. Power rating is same as coax cable used power rating. Snap On and Slip on Feed line chokes available in sizes to fix cables with outside diameters of 1/4", 3/8", 1/2", 3/4", 1" - check website for other size options. The 5 bead, 1/2" model was previously part # BA-8 Testimonial: KI7AY
.75″/19.5mm max Cable Size Chokes (includes beads and shrink wrap)
Wanted to let you know that I was having a problem with RFI on 40m, but immediately after installing your Slip On Coax Feed Line Choke -1/2"/12.7mm cable, 1.8-300 MHz on a new RG-213 jumper between the IC-9100 and tuner, IT WENT COMPLETELY AWAY!
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.
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Bead dimensions are shown in the picture below and in the table as A, B, C
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)
Multi-turn Common Mode Choking Impedance Increase Example (FB56-43)
Ferrite Bead relative size comparison
Left to right sizes: FB56 (ID = .25″), FB102 (ID=.505″), FB103 (ID=.77″)
SLIP ON Sizes for Heliax and Coax Cable
Cascaded Common Mode Chokes/Line Isolators/1:1 Baluns
 RG58 4 turns on 2 FB102-31 for 2000 ohms choking impedance |
 RG58 12 turns on FT240-43 for 4000-6000 ohms choking impedance |
Handy Wire Size reference for ferrite bead sizes needed
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Connector already on cable? See Snap On Ferrite Beads for convenient installation on cables with connector already installed.