BIG SIGNAL RF Choke
RF Choke for Reducing Common-Mode Currents on Coaxial Feed Lines
The BIG SIGNAL RF Choke is designed to reduce common-mode currents that may flow along the outside surface of the coaxial cable shield, helping improve isolation between the antenna, feed line, and station equipment.
Built and optimized with materials selected for RF applications, it is available in three power versions: 300 W, 2 kW, and 4 kW PEP, allowing you to select the most appropriate model for your station's requirements.
Type: RF choke / common-mode isolator
Available versions: 300 W / 2 kW / 4 kW PEP
Installation: in-line with the coaxial feed line
Primary function: common-mode current suppression
Applications: HF antennas / base stations / RF systems
Purpose: improve isolation between the antenna, feed line, and station
Available in 300 W • 2 kW • 4 kW PEP
Three versions designed to cover different power levels, from moderate-power stations to high-power RF installations.
Why Install an RF Choke?
• Reduces common-mode currents
Presents a high impedance to unwanted currents that may flow along the outside surface of the coaxial cable shield, helping prevent the feed line from becoming an unintended part of the radiating system.
• Helps reduce unwanted RF in the shack
Reducing common-mode currents can decrease the amount of RF that reaches the station along the outside of the coaxial feed line.
• Can reduce RFI issues
By limiting unwanted RF currents on the feed line, it can help reduce certain types of interference, disturbances, and unwanted coupling between electronic devices.
• Helps preserve antenna performance
Reducing unwanted radiation from the coaxial feed line can help maintain a radiation pattern closer to the antenna's intended design.
• Improves isolation between the antenna and station
The choke provides a high-impedance barrier to common-mode currents, promoting better decoupling between the radiating system, coaxial feed line, and radio equipment.
Better Control of Your RF Installation
The BIG SIGNAL RF Choke can be installed in-line with the coaxial feed line to help control common-mode currents and improve RF isolation between the antenna and station. Its three power versions make it suitable for a wide variety of installations.
• Installations with unwanted RF in the shack.
• Systems with common-mode currents on the coaxial feed line.
• Stations experiencing RFI or equipment-coupling issues.
• Antennas affected by unwanted participation of the coaxial feed line in the radiating system.
• Installations requiring improved isolation between the antenna and station.
• Stations with different power requirements, from 300 W to 4 kW PEP.
Less Common Mode. Better Isolation. Three Power Levels.
The BIG SIGNAL RF Choke range, available in 300 W, 2 kW, and 4 kW PEP versions, is designed to help reduce common-mode currents on coaxial feed lines and improve isolation between the antenna, feed line, and station.
Technical Specifications
Frequency range: 1 – 52 MHz
Impedance: 50 Ohms / 50 Ohms
Transformation ratio: 1:1
Insertion loss: < 0.1 dB
Maximum power: 300 W PEP
Type: RF choke / common-mode isolator
Function: common-mode current suppression on coaxial feed lines
1 – 52 MHz • 300 W PEP • 50 Ohms • < 0.1 dB
The BIG SIGNAL RF Choke 300 W provides an operating range of 1 to 52 MHz, maintains a nominal impedance of 50 Ohms with a 1:1 ratio, and features insertion loss below 0.1 dB, with a specified maximum power rating of 300 W PEP.
Construction and Materials
• RG-400 coaxial winding
The winding is made with RG-400 coaxial cable, selected for RF applications and to provide stable performance throughout the specified operating range.
• Ni-Zn toroidal core
Uses a low-initial-permeability nickel-zinc (Ni-Zn) ferrite toroid as the magnetic element to provide the required impedance to common-mode currents.
• Stainless steel hardware
Fastening hardware is made from stainless steel, providing mechanical strength, corrosion resistance, and long-term durability.
• SO-239 connector with PTFE insulation
Equipped with an SO-239 connector featuring PTFE insulation, suitable for RF applications and the specified power level.
Wide Frequency Coverage. 300 W PEP. Minimal Insertion Loss.
The BIG SIGNAL RF Choke 300 W combines an operating range of 1 to 52 MHz, insertion loss below 0.1 dB, and a specified maximum power rating of 300 W PEP, using RG-400 coaxial cable, a Ni-Zn ferrite toroidal core, and an SO-239 connector with PTFE insulation.
The purchase of the products is always made on request. We manufacture all products, so manufacturing times can be added. That is why the final price of the purchase, as the final price of the shipping costs will be confirmed in an email sent afterwards.
The form of payment will be made once the email is received, so at all times you can cancel the order informing us of the process.
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Tras muchos quebraderos de cabeza, y mucho tiempo invertido en probar soluciones infructuosas para poder trabajar en FT8 desde mi estación móvil, dada la imposibilidad de configurar debidamente la entrada/salida de audio por un problema de RF, decidí probar este Choke, con el siguiente resultado:
INCREÍBLE: Ha sido poner este Choke (1 minuto de instalación) y se han abierto para mi las puertas del FT8, las cuales antes tenía totalmente cerradas ?. La RF ha desaparecido por completo: se ajunta mucho mejor la ROE, no interfiere en mi ordenador portátil, puedo ajustar los niveles de audio, etc.
En unos minutos de prueba he conseguido trabajar varias estaciones Usa, varias de Argentina, Venezuela, Israel, Turquía, y prácticamente toda Europa.
Muchas gracias, !Buen trabajo!
Lo instale hace tres días, yo no había utilizado nunca un Choke de RF y la verdad es que estoy muy sorprendido de los buenos resultados conseguidos. Un saludo cordial de EA1GOZ Julian.