Slip On Ferrite Beads

Slip On Feed Line Common Mode Line Isolator/Choke - 1/2"/12.7mm coax cable, 1.8-100 MHz, 5,10,15, 20 bead option, Mix 31

SKU SLO31-1/2-5
$19.95
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Slip On Feed Line Common Mode Line Isolator/Choke - 1/2"/12.7mm coax cable, 1.8-100 MHz, 5,10,15, 20 bead option, Mix 31
Product Details
Brand: Palomar Engineers
MPN: SLO31-1/2-NN, NN=5, 10, 15, 20
Country/Region of Manufacture: USA
Effective Frequency Range (MHz): 3-300 (5 bead), 1.8-300 (10, 15 bead)
PEP Power Rating (watts): same as coax cable rating
Common Mode Attenuation (db): see graph
Estimated Insertion Loss (db): .025
Input Connector Type: none
Output Connector Connector Type: none
Ground Connector (Y/N): none
Enclosure Size (LxWxH inches): none

1/2″/12.7mm max Cable Size Chokes

Model SLO-1/2 family of chokes are for use with ½” coax cable like RG-8, RG-213, 9913, LMR-400 and similar cables up to ½” diameter – works on all cable impedances (50, 62, 75, 90 ohms etc). 80-6 meters.Choose SLO-1/2 (5 beads) or for extended choking, choose SLO-1/2E (10 beads) or for super extended choking choose SLO-1/2SE (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 up to 10,000 ohms choking.

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
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!


 
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.

 NOW WITH QUANTITY PRICING FOR CLUB , VOLUME PURCHASERS!

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 Sales@Palomar-Engineers.com  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

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