Snap On Sleeve Choke - 1"/25.4mm cable - 5 Bead
Use for 1″ Cable
Typical Impedance per split bead: 1 MHz: 45 5 MHz: 90 ohms, 10 Mhz: 125 ohms, 25 MHz: 218 ohms, 100 MHz: 375 ohms, 250 MHz: 340 ohms
Select 10 bead version for use on 160 meters and above (10 bead version with optional heat shrink shown in picture).
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
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: