RFI chokes
Our high-quality common-mode chokes (RFI chokes) effectively reduce common-mode currents and interference on coaxial cables. They improve reception, prevent unwanted radiation, and help protect your radio equipment.
Ideal for amateur radio, field days, POTA, SOTA, or fixed station operation. Whether for dipole, end-fed, or portable antennas – here you will find the right choke for clear, interference-free signals.
Common-Mode Choke / RFI-Choke Standard 1 KW This common-mode choke prevents the shield of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It also serves to match the unbalanced coaxial cable to balanced antennas and can therefore be used as a “1:1” balun.Built according to the W2DU principle, the 1 KW common-mode choke is extremely broadband and low-loss. A large number of high-permeability ferrites are threaded onto high-temperature-resistant PTFE coaxial cable, shrink-wrapped, and fitted with appropriate connectors. This makes it easy to integrate into the coaxial feed line.This Standard common-mode choke is approximately 45 cm long, very broadband, and provides about 1000 ohm of common-mode impedance in the frequency range from 80m to 2 m. It is weatherproof shrink-wrapped and has two high-quality PL259 connectors with PTFE dielectric and gold-plated contacts at the ends. A PL259 connector with PTFE and gold-plated contacts is included. Important Notice:When using an End Fed antenna, do not place the common-mode choke directly at the feed point of the antenna! A section of coaxial cable with a length of ≥ λ 0.05 (e.g., about 4.2 m on 80 m band) should be inserted between the End Fed transformer and the common-mode choke.Informationen gemäß Art. 19 GPSR Adresse des Herstellers: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net Adresse der verantwortlichen Person: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net
This common-mode choke prevents the shield of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It also serves to match the unbalanced coaxial cable to balanced antennas and can therefore be used as a “1:1” balun. Built according to the W2DU principle, the Wideband 2 KW choke is extremely broadband and low-loss. A large number of high-permeability ferrite sleeves (28 pieces) are threaded onto high-temperature-resistant PTFE coaxial cable, shrink-wrapped, and fitted with suitable connectors. This makes it easy to integrate into the coaxial feed line. The Wideband 2 KW common-mode choke is approximately 70 cm long, very broadband and provides about 1500 ohm of common-mode impedance in the frequency range from 160 m to 2 m (1 MHz to 200 MHz). It is weatherproof with shrink wrap and has two high-quality PL259 connectors with PTFE dielectric and gold-plated contacts at the ends. A PL259 connector with PTFE and gold-plated contacts is included. Important Notice: When using an End Fed antenna, do not place the common-mode choke directly at the feed point of the antenna! A section of coaxial cable with a length of ≥ λ 0.05 (e.g., about 4.2 m on the 80 m band) should be inserted between the End Fed transformer and the common-mode choke. Informationen gemäß Art. 19 GPSR Adresse des Herstellers: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net Adresse der verantwortlichen Person: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net
This pre-assembled coaxial cable with integrated RFI choke for End Fed antennas is ready for immediate use. Thanks to its design based on the W2DU principle, the common mode choke is extremely broadband and low-loss. It effectively prevents the shielding of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It therefore provides effective protection against unwanted RF interference. It also serves to adapt the unbalanced coaxial cable to balanced antennas and can therefore also be used as a “1:1” balun. A variety of highly permeable ferrites are threaded onto lightweight HF-195 FX-ZH low-loss coaxial cable, shrink-wrapped and assembled with connectors as required. The integrated RFI choke (common mode choke) is installed at the end of the cable after 2.10m for the 10-40m bands or after 4.20m for the 10-80m bands. We offer lengths of 10, 15 and 20m. Other lengths can be produced on request. The lightweight coaxial cable with integrated RFI choke (common mode choke) is also ideal for portable use when traveling, QRP, COTA, POTA, IOTA, SOTA (Summit on the Air) or DX expeditions. 50 Ohm HF195 FX-ZH coaxial cableReady for immediate usefor 10-40m or 10-80m bandPlug and PlayChoice of cable lengthConnector of your choicePower limit Max: 250W PEP SSB Translated with DeepL.com (free version)
This pre-assembled coaxial cable with integrated RFI choke for QRP is ready for immediate use. Thanks to its design based on the W2DU principle, the common mode choke is extremely broadband and low-loss. It effectively prevents the shielding of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It therefore provides effective protection against unwanted RF interference. It also serves to adapt the unbalanced coaxial cable to balanced antennas and can therefore also be used as a “1:1” balun. A variety of highly permeable ferrites are threaded onto lightweight RG316 low-loss coaxial cable, shrink-wrapped and assembled with connectors as required. The integrated RFI choke (common mode choke) is installed at the end of the cable after 30cm. We offer lengths of 5,20m, 7,70m and 10,20m. Other lengths can be produced on request. The lightweight coaxial cable with integrated RFI choke (common mode choke) is also ideal for portable use when traveling, QRP, COTA, POTA, IOTA, SOTA (Summit on the Air) or DX expeditions. 50 Ohm high Quality RG316 coaxial cableReady for immediate usePlug and PlayBNC Connector with PTFEChoice of cable lengthPower limit Max: 100W PEP SSB Informationen gemäß Art. 19 GPSR Adresse des Herstellers: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net Adresse der verantwortlichen Person: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net
Our (W2DU) Feedline Chokes are built strictly from premium quality material.The PL-259 UHF coax connectors, double-UHF female connector and coax cable are sourced from our long time German suppliers and are well proven.The ferrite cylindrical cores are sourced directly from the manufacturer.You should plan about 1 hour of work-time for the construction of the RF Choke. You will need a soldering iron and solder, a heat gun (lighter if necessary) and scissors or cutting tool to strip the cable.These broadband RF Chokes have about 1000 Ohm Common Mode Impedance from 160 - 6m.The kit contains the following material for building the RF Choke:50 cm coax cable RG-14250 cm heat shrink tubing 9/3mm2x PL-259 connectorPL double female connector)12x ferrite cores (cylindrical) CST9.5/5.1/15-3S46x ferrites cores (cylindrical) LFB095051-000Download the illustrated assembly instruction as PDF here Hersteller: Nach EU 2023/988 Produktsicherheitsverordnung (GPSR) Spiderbeam GmbH Geschäftsführer: Dipl.-Ing. Cornelius Paul Otto-von-Guericke-Str. 3 03130 Spremberg Deutschland Tel: +49 3563 989812 Fax: +49 3563 989812 E-Mail: office@spiderbeam.com Verantwortliche Person: Spiderbeam GmbH Geschäftsführer: Dipl.-Ing. Cornelius Paul Otto-von-Guericke-Str. 3 03130 Spremberg Deutschland Tel: +49 3563 989812 Fax: +49 3563 989812 E-Mail: office@spiderbeam.com
CCMC30 Common Mode Noise Filter Noise filters are nothing new and are often used for transmitting purposes. They are used to prevent unwanted radiation via the coax shielding. It is less known that they can also suppress unwanted radiation when receiving signals, especially when an active antenna is used. However, in this case, the situation is reversed: en route to the antenna, unwanted interferences from electric home appliances can be effectively eliminated. NTi's Coaxial Common Mode Noise Filter (CCMC30) has been especially optimized for maximum common mode noise rejection of >30dB wide band in the frequency range of 150kHz - 30MHz. With slight limitations a much wider frequency range is covered. In the medium wave range for example a noise suppression of up to 45 dB can be achieved. This is possible by using a cascaded system of ferrite cores with various frequency dependent material properties, combined with high quality coaxial cable. For outdoor use, the system is housed in a water-proof enclosure. We recommend to connect the CCMC30 as closely as possible to the receiver.With regard to efficient noise suppression, the CCMC 30 is not very much different from the galvanic isolator GI1000. However, the CCMC30 performes down to lowest frequencies including DC voltage, in contrast to the GI1000, which blocks DC voltages and very low frequencies. The CCMC30 can thus be connected directly to the coax cable which passes the supply voltage or the control signals to the active antenna. A series connection of the GI1000 directly connected to the receiver followed by the CCMC30 right behind the power inserter may result in an even better performance. Technical Data Guaranteed frequency range: 150 kHz – 30 MHz Common Mode Wave suppression: >30 dB: 150 kHz -30MHz (>20 dB: 30kHz-60MHz) Insertion loss: <1 dB (up to max. 150 MHz) Size: 100x68x50mm (132mm with BNC connectors) Connectors: 2x BNC 50Ohms Weight: 320g Made in Germany
1 – 30 MHz Common mode filter with bifilaire windings for optimal attenuation There are many types of common mode chokes available, HF Kits opts for a common mode choke with bifilar windings for optimal filtering. This 1 – 30 MHz common mode current filter is optimized for the 80 and 160 meter band. In this case a FT240-31 toroidal core with optimal performance for the lower frequency range is used. The 1 – 30 MHz common mode choke performs very well on the entire HF spectrum. The attenuation is therefore around 30 dB across the entire HF frequency spectrum. This filter is therefore a real all-rounder for amateurs who want to work from 160 meters to 10 meters. Even people who deal with LPAM (Medium Wave) can use this filter. The main reason for using a common mode choke is to ensure that the coax cable’s shield does not become part of the antenna system and will radiate unintentionally. This has all sorts of nasty effects, think of: interference issues, disrupted radiation pattern of the antenna and a higher noise level. This last point is because not only does the coax cable’s shield radiate when you transmit, but the shield also works as a receiving antenna. Because the coax cable often makes a considerable trip within the house, close to interference sources (mains, PLC etc…) It is useful to eliminate these sources of interference. Any way, Good reason to use a common mode choke. The effect of this common mode choke with bifilar windings is difficult to predict. This depends on local circumstances. Think of: antenna type, antenna placement, type of feed line, feed line placement and especially local sources of interference. There are manufacturers that promise in advance a significant drop in interference, however this is not real. There are cases where the noise level decreases by two to three S points, but also cases where the filter has almost no effect. This kit includes: IP65 enclosure 100 x 100 x 55 mm (Polycarbonat) Ringcore Amidon FT240-31 Winding wire 18 AWG – 4x 85cm PTFE 19 x 0.25 mm copper “Silver plated” Toroid mounting plate Stainless steel M3 6mm screws 4x Stainless steel M3 Spring washer 4x 2x PL 259 Chassis 2x M3 cable lug 8x Stainless steel M3 Bolt 12mm 8x Stainless Steel M3 Nut 8x Stainless steel M3 washer 8x Stainless steel M3 tooth washer IMPORTANT! Do not place the common mode choke in case of an End Fed antenna directly at feed point of the antenna.Construction Manual in Englisch
1 – 30 MHz Common mode filter with bifilaire windings for optimal attenuation There are many types of common mode chokes available, HF Kits opts for a common mode choke with bifilar windings for optimal filtering. This 1 – 30 MHz common mode current filter is optimized for the 80 and 160 meter band. In this case a FT240-31 toroidal core with optimal performance for the lower frequency range is used. The 1 – 30 MHz common mode choke performs very well on the entire HF spectrum. The attenuation is therefore around 30 dB across the entire HF frequency spectrum. This filter is therefore a real all-rounder for amateurs who want to work from 160 meters to 10 meters. Even people who deal with LPAM (Medium Wave) can use this filter. The main reason for using a common mode choke is to ensure that the coax cable’s shield does not become part of the antenna system and will radiate unintentionally. This has all sorts of nasty effects, think of: interference issues, disrupted radiation pattern of the antenna and a higher noise level. This last point is because not only does the coax cable’s shield radiate when you transmit, but the shield also works as a receiving antenna. Because the coax cable often makes a considerable trip within the house, close to interference sources (mains, PLC etc…) It is useful to eliminate these sources of interference. Any way, Good reason to use a common mode choke. The effect of this common mode choke with bifilar windings is difficult to predict. This depends on local circumstances. Think of: antenna type, antenna placement, type of feed line, feed line placement and especially local sources of interference. There are manufacturers that promise in advance a significant drop in interference, however this is not real. There are cases where the noise level decreases by two to three S points, but also cases where the filter has almost no effect. This kit includes: IP65 enclosure 100 x 100 x 55 mm (Polycarbonat) Ringcore Amidon FT240-31 Winding wire 18 AWG – 4x 85cm PTFE 19 x 0.25 mm copper “Silver plated” Toroid mounting plate Stainless steel M3 6mm screws 4x Stainless steel M3 Spring washer 4x 2x PL 259 Chassis 2x M3 cable lug 8x Stainless steel M3 Bolt 12mm 8x Stainless Steel M3 Nut 8x Stainless steel M3 washer 8x Stainless steel M3 tooth washer IMPORTANT! Do not place the common mode choke in case of an End Fed antenna directly at feed point of the antenna.
Common-Mode Choke / RFI-Choke Standard (1 KW) – N-Version This common-mode choke prevents the shield of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It also helps match unbalanced coaxial feed lines to balanced antennas and can therefore be used as a 1:1 balun.Built according to the proven W2DU principle, this standard common-mode choke offers broadband performance with very low loss. A series of high-permeability ferrite cores are threaded onto high-temperature-resistant PTFE coaxial cable, shrink-wrapped, and fitted with high-quality N connectors, allowing easy integration into the coaxial feed line.The choke is approximately 48 cm long and provides around 1000 ohms of common-mode impedance across a wide frequency range from 80 m to 2 m. It is weatherproof, shrink-wrapped, and equipped with N-type connectors featuring PTFE dielectric and gold-plated contacts on both ends. Important Installation Note:When using an end-fed antenna, do not install the common-mode choke directly at the feed point. A section of coaxial cable with a minimum length of λ 0.05 (for example approx. 4.2 m on the 80 m band) should be installed between the end-fed transformer and the choke.FeaturesFrequency range: 3 MHz to 200 MHzAttenuation: approx. 25 dB – common-mode impedance approx. 1000 ΩConnectors: N-type male to N-type femalePower handling: approx. 1000 WWeight: 0.3 kgLength: 48 cmInformationen gemäß Art. 19 GPSR Adresse des Herstellers: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net Adresse der verantwortlichen Person: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net
Common-Mode Choke / RFI-Choke Wideband (2 KW) – N-Version This wideband common-mode choke prevents the shield of the coaxial cable from becoming part of the antenna system and radiating unintentionally. It also helps match an unbalanced coaxial feed to balanced antennas and can therefore be used as a 1:1 balun.Built according to the W2DU principle, the wideband 2 KW choke delivers extremely broadband, low-loss performance. A large number of high-permeability ferrite sleeves are threaded onto high-temperature-resistant PTFE coaxial cable, shrink-wrapped, and fitted with high-quality N-type connectors, making it easy to integrate into your coaxial feed line.The choke is approximately 72 cm long and provides around 1500 ohms of common-mode impedance over a wide frequency range from 160 m to 2 m (1 MHz – 200 MHz). It is weatherproof, shrink-wrapped, and equipped with premium N-type connectors (plug and socket) with PTFE dielectric and gold-plated contacts.Important Installation Note:When using an end-fed antenna, do not install the choke directly at the antenna feed point. A section of coaxial cable with a minimum length of ≥ λ 0.05 (for example about 4.2 m on the 80 m band) should be placed between the end-fed transformer and the choke. FeaturesFrequency range: 1 MHz to 200 MHzAttenuation: approx. 32 dB – common-mode impedance approx. 1500 ΩConnectors: High-quality N-type male to N-type femalePower handling: approx. 2000 WWeight: 0.5 kgLength: 72 cmInformationen gemäß Art. 19 GPSR Adresse des Herstellers: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net Adresse der verantwortlichen Person: Bonito - Gerichtsweg 3 - 29320 Hermmansburg - anfragen@bonito.net- www.bonito.net