1:1 Snap On Common Mode Choke Kits for Coax Cable
Connector already on the cable? Don’t want to remove it? Use Snap On Ferrite split bead kits that clamp over the cable.
SNAP ON Sizes for Heliax and Coax Cable
Use for 1/4″ Cable – RG-58, RG8X, LMR-240, etc
For 1/4” cables use five FSB31-1/4 split beads to get the same performance as Model BA-58 balun kit (80-10 meters) or ten FSB-1/4 split beads for 160-10 meters similar in performance to the BA-58E.
Typical Impedance per split bead: 10 Mhz: 100 ohms, 25 Mhz: 163 ohms, 100 Mhz: 275 ohms, 250 Mhz: 275 ohms
For 80-6 meters use – Five FSB31-1/4 ………………..Kit 105……….$13.75
For 160-6 meters use – Ten FSB31-1/4 ………………..Kit 106……….$25.00
Typical choking impedance over the range of 1-61 MHz:
Use for 1/2″ Cable – RG8, RG213, LMR-400, etc.
For 1/2” cables use five FSB31-1/2” split beads to get the same performance as Model BA-8 balun kit. You can also use the 1/2″ size for 1/4″ cable with multiple turns for even greater effectiveness.
Typical Impedance per split bead: 10 Mhz: 90 ohms, 25 Mhz: 156 ohms, 100 Mhz: 250 ohms, 250 Mhz: 305 ohms
For 80-6 meters use – Five FSB31-1/2 ………………..Kit 110………..$30.00
For 160-6 meters indoor use – Ten FSB31-1/2 …….Kit 111……….$55.00
Typical choking impedance over the range of 1-61 MHz (Kit 110 same as BA-8, Kit 111 same as BA-8E):
The beads clamp to the cable and may be operated as is for indoor use. However, it is strongly suggested that they be covered to protect the plastic covers from weathering – use electrical tape for best results or heat shrink to ensure longer life. All kits come with instruction manual which covers assembly and application tips.
Application Note for using these Snap On split beads: How Many Chokes do I need?
As you can see from the above table and graph, 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 1/4 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 on individual beads are shown below.
Use for 3/4″ Cable LDF-4, Heliax(R), LMR-600, etc.
FSB31-3/4 For 3/4″ cable Mix 31 for 1-300 Mhz, 1.65″/42MM long
Typical Impedance per split bead: 10 Mhz: 50 ohms, 25 Mhz: 95 ohms, 100 Mhz: 195 ohms, 250 Mhz: 322 ohms
Price:……$7.50 each or buy 10 pack (Model # FSB-3/4-10) for $65
Kit 117, 100-300 Mhz Common Mode Choke (FSB-3/4-3) …… $22.50
Kit 118, 40-300 Mhz Common Mode Choke (FSB-3/4-4) …… $30.00
Kit 119, 3-300 Mhz Common Mode Choke (FSB-3/4-5) …… $37.50
FSB31-1 or Big Clamp On Ferrite Split Bead – ID = 1 inch
Measurement size of FSB-1 – A great new Snap On product for multi-turn RG-8 size cable or use for single turn on Heliax 7/8″ cable if you run super power. 1″ ID takes a lot of cable! Also works with RG-8X cable with more turns for greater effectiveness.
FSB31-1 Typical Use – 3 turns of 1/” cable
Here is an AIM 4170 choking impedance chart showing 1, 2 and 3 FSB-1 on a 5 foot piece of coax (see above picture).
Application Note on FSB31-1: Choose the number of FSB31-1’s you need depending on the amount of choking needed. Note this chart is for a single, 3 turn loop with 1, 2 or 3 FSB-1’s. You may put more than one 3 turn loop in series to get additional choking of common mode currents. For 80-10 meters use three sets of 1 FSB-1 though 3 turns to get 3X the choking impedance of the FSB-1 x 1 graph above. To emphasize lower frequencies use multiple FSB-1 through the individual 3 turn loops. For comparison our Super Choker has 7 turns thru 5 cores and peaks near 6K ohms on 160 meters. We use 3 turn loop examples because this is the max turns you can get with RG-8 size cable (1/2″). Expect higher choking Z if you use RG-8X and more turns. Note: LMR-400 can get 4 turns.
For added choking you cascade the chokes in series as shown below:
FSB-1 For multiple turns of smaller cable using 1″ inside diameter, 2.22″ outside diameter, length 1.69″- 31 Mix for 1-150 Mhz
$19.50 each (Model # FSB31-1) or buy 10 pack for $175 (Model # FSB31-1-10) or 3 pack in box for $55 (Model FSB31-1-3)
Specially designed for high power operations, Kit 125 is a high power choke consisting of 10 FSB-1 ferrite cores providing a measured choking impedance of 1000 ohms between 26-30 Mhz. The power rating is equal to the power rating of the feed line cable at a unity SWR (1.0:1) and slightly less for higher SWR. Ideal for Heliax(TM) cable and LMR type cables with outside diameters < 1.0?. For power over 10KW, use two baluns in series. Shim heliax or remove outside protective sheathing if needed . Heat shrink cover included as shown.
Model # – Kit 125 – High Power Snap On Common Mode Choke Kit ………$175 + $15 shipping
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