Ring - Mix 31 - RFI Range: 1-300 MHz
Mix # 31, Material: MnZn, Initial Permeability: 1500
Refine by On Sale
FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Bulk Pack of 10FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Bulk Pack of 10SKU F240-31-10List price $100.00 Save 10%$89.95On Sale
FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Case of 100FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Case of 100SKU F240-31-100List price $1,000.00 Save 21%$795.00On Sale
FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Mini Pack of 3FT240-3I, ID=1.4", AC/DC/Coax Noise Filter, RFI Range 1-300 MHz, Mini Pack of 3SKU F240-31-3List price $34.95 Save 14%$29.95On Sale
FT400-3I, ID=3", RFI Range 1-300 MHz, Case of 25FT400-3I, ID=3", RFI Range 1-300 MHz, Case of 25SKU F400-31-25List price $873.75 Save 5%$829.95On Sale
Ferrite Ring Combo Pack, FT140 - .9" ID, 15 Rings - Mix 43, 61, 77, RFI Range .1-2000 MHzFerrite Ring Combo Pack, FT140 - .9" ID, 15 Rings - Mix 43, 61, 77, RFI Range .1-2000 MHzSKU FRCP-140-15List price $58.35 Save 14%$49.95On Sale
Ferrite Ring and Snap On Combo Pack - 10 Rings (1.4" ID) + 10 Snap On Beads (1/2" ID) - Mix 31 (RFI Range 1-300 MHz) FREE USA SHIPPINGFerrite Ring and Snap On Combo Pack - 10 Rings (1.4" ID) + 10 Snap On Beads (1/2" ID) - Mix 31 (RFI Range 1-300 MHz) FREE USA SHIPPINGSKU FRSCP-31-20List price $155.00 Save 10%$139.95On Sale
Ferrite Sampler Pack, Mix 31, RFI Range 1-300 MHz - 25 filters- 1.4" ID Ring, Snap on 1/4, 3/8, 1/2, 3/4, 1, Slip On 1/2, 1/4Ferrite Sampler Pack, Mix 31, RFI Range 1-300 MHz - 25 filters- 1.4" ID Ring, Snap on 1/4, 3/8, 1/2, 3/4, 1, Slip On 1/2, 1/4SKU FSP-31-25List price $127.00 Save 22%$99.50On Sale
Ferrite Snap on/Ring Combo Pack, Mix 31, RFI Range 1-300 MHz - 16 filtersFerrite Snap on/Ring Combo Pack, Mix 31, RFI Range 1-300 MHz - 16 filtersSKU FSRCP-31-16List price $112.00 Save 15%$95.00On Sale
Multi-Ring/Multi-Snap On Combo Pack, Mix 31, RFI Range 1-300 MHz - 17 filtersMulti-Ring/Multi-Snap On Combo Pack, Mix 31, RFI Range 1-300 MHz - 17 filtersSKU MRSCP-31-17List price $112.00 Save 15%$95.00On Sale
RV/Trailer Multi-Ring/Multi-Snap On Combo Pack, Mix 31, RFI Range 1-300 MHz - 17 filtersRV/Trailer Multi-Ring/Multi-Snap On Combo Pack, Mix 31, RFI Range 1-300 MHz - 17 filtersSKU RVCP-31-17List price $112.00 Save 15%$95.00
HF 1-61 MHz coax feed line common mode chokes
Ring - Mix 31 - RFI Range: 1-300 MHz
Mix # 31, Material: MnZn, Initial Permeability: 1500










1:1 feed line Chokes (also known as feed line current chokes, common mode chokes, line isolators, current mode chokes, and 1:1 baluns/ununs) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call a CUBE™. All 1:1 chokes are ferrite based and are designed for 50 ohm coaxial cable input and 50 ohm output. 1:1 Ferrite toroidal or bead chokes have a higher choking impedance than our popular Sleeve Chokes and various models are available for specific frequency ranges and power levels.
1:1 Chokes are useful for choking common mode currents that may flow on the exterior of the coax cable shield while allowing the signals on the interior of the shield and the center conductor to flow unaffected and keeping the common mode current on the antenna. They isolate the coax shield and prevent it from becoming part of the antenna system.
1:1 Chokes are useful between balanced lines for center fed dipoles at their fundamental frequency (468/f (MHz), beam antennas with a 50 ohm balanced driven element, G5RV, loops, yagis, NVIS antennas, mobile installations, portable antennas and anywhere common mode current (or RFI) is a problem. They are also helpful between transmitter and linear amplifier or between linear amp and antenna tuner or as isolation chokes where higher choking impedance is needed (in the range of 2K-7K ohms).
1:1 Chokes are also very useful as feed line current chokes at the “radio end” of the antenna (we call them coax noise filters) where they choke/filter common mode current induced onto the coax shield from radiated waves (from your antenna, and other sources such as DSL routers, computer devices, plasma TVs, etc. originating in your house or your neighbor’s house). For RFI issues see RFI/EMI Solutions for general use or for specific radios and devices.
For best results we recommend a 1:1 choke at the “antenna end” of the coax and a coax noise filter at the “radio end” of the coax. (A side benefit is a reduction in noise level caused by common mode currents). 1:1 chokes are also available as Sleeve Chokes (Slip on or Snap on) for ease of installation and light weight on the antenna.