In 2017 we created an exclusive partnership with Hugo of ON7FU Ferrite Applications.

Together with him we developed a special version balun with we added to our product porto folio and to our webshop, for in case users want to play with dipoles fed with open wire feedlines connected to Stockcorner Tuners. This JC-balun is designed and produced by Hugo ON7FU. Constructed to the high quality standard of ON7FU products.

If you need any other type of balun please visit the website of Hugo. He can make, test and sell any version on request.

ON7FU Ferrite Applications - Click here for the website 


 Broadband transmission line transformer (Common-Mode Choke) with impedance ratio of 1/1.
 Transmission line winding designed for high voltage withstand.
 Frequency range: 1,5MHz tot 30 MHz,
 Large ferrite volume, preventing saturation under high power conditions.
 Use of special teflon insulated transmission line with high temperature resistance and high power / voltage withstand.
 Circuit installed in waterproof housing and impregnated / potted with synthetic resin.
 Maximum power: 1200W PeP. (ICAS)

 Standard version, optimized for the mid / high HF bands, using "Mix 43" ferrite toroid core.
 Variant optimized for the low HF bands, using "Mix 31" ferrite toroid core. (only this "mix31" version is on stock)
 Custom versions on request.

When installed in a ladderline, this choke will remove, over a broad frequency range, any common-mode current, without affecting the differential mode signal current, thus minimizing radiation from the feedline and optimizing antenna radiation pattern.

This product is a special variant of the standard 1/1 Common-Mode Choke, utilizing a symmetric transmission line pair that is designed for maximal inter-winding breakdown voltage. To achieve this goal, the teflon insulated wires are additionally slipped into teflon sleeves having a dielectric breakdown rating of 48 kV/mm. This is needed as the CMC is deployed in a random impedance environment. 

Suitable for deployment at any position in the balanced feedline.
Use of the BALUN / Line Isolator beyond the specified frequencyor power range can destroy it and cause safety risks.
The product must be considered as a sub assembly, intended to be a part of an amateur radio antenna installation.
The product is exclusively intended for outdoor use, in a fire safe and explosion safe environment.
Compatible with JC-4, JC-3 and similar antenna tuners.

M6 stainless steel wire terminals on input and output.

The user cannot open the balun. No service parts inside.

This special version you can find in the webshop of Stockcorner


About Hugo Cnudde

Born in 1959. Amateur radio call sign ON7FU since 1978. Professionally active in RF design and development and EMC/ Safety compliance testing. Education: Master of Science in EMC Technology and radio Frequency Communication. (UofY)