Mobile Station RFI Kits

Snap On RF Choke/Isolator - 1/2"/12.7mm cable -5/10/15 Bead Option, 3-300 MHz

SNO31-1/2-5
$25.95
In stock
1
Product Details
Brand: Palomar Engineers
MPN: SNO-1/2-5
Country/Region of Manufacture: United States
Effective Frequency Range (MHz): 5 bead: 3-300, 10,15 bead: 1.8-300
PEP Power Rating (watts): same as coax cable rating
Choking Impedance Range (ohms): 5 bead: 200-900, 10 bead: 400-1400, 15 bead: 600-1700
Common Mode Attenuation (db): 5 bead: 9-20 db, 10 bead: 16-24 db, 15 bead: 17-28 db
Estimated Insertion Loss (db): .025

Use for 1/2″ Cable – RG8, RG213, LMR-400, etc.

For 1/2” cables use five split beads for 80-10 meters (3-30 MHz) or ten split beads for 160-10 (1.8-30 MHz) meters or use 15 for even higher choking for 1-10 MHz. For 144 MHz use only 4 beads as they will provide > 500 ohms. Typical common mode suppression is -9 to 30 dB depending upon the number of beads and frequency. Quite often 20 dB is considered the minimum effective reduction.

Typical Impedance per split bead: 10 MHz: 90 ohms, 25 MHz: 156 ohms, 100 MHz: 250 ohms, 250 MHz: 305 ohms

A minimum impedance of 500 ohms is needed for 50 ohm cable or 10 times the cable impedance for other cables to make a measurable difference in common mode current suppression.

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.

As you can see from the impedance vs frequency graph, you can very effectively increase the choking impedance by increasing the number of beads on the cable.

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.

tech note: For RFI frequencies below 3.75 MHz, choose SNO75-1/2-5, 10 or 15 for improved common mode rejection

Note: Ferrite beads may be hexagonal or square shape depending on inventory on hand at time of order.

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Mobile RFI kits work two ways: They suppress RFI from on board computers and other sensing/control devices in your vehicle that may cause your radio to be a VICTIM of RFI, and second they suppress RFI generated by your radio as a SOURCE which may affect your on board computers or other devices.  Mobile operations of HF radios (1-30 Mhz) tend to experience more RFI effects than VHF/UHF mobile stations.  If you have both HF and VHF installations in your vehicles, you may need both kits.

To address separate solutions we have developed two separate RFI kits: one for HF (1.8-300 MHz) mobile installations and another for VHF/UHF (30-1000 MHz) mobile installations.  Each kit uses the appropriate ferrite mix for the frequency range desired.