Another small efficient matching transformer for an EFHW – 2643251002 – #2 – prototype bench measurement continued the development of a transformer design. This article presents a Guanella 1:1 (current) balun (or common mode choke) using the same type of core.
Above, the EFHW transformer prototype.
Above is a Simsmith model of the 6t balun common mode impedance Zcm on a 2543251002 core, and measured (squares) impedance, the model is calibrated to the measured self resonant frequency.
The core is quite suited to both the EFHW transformer and a common mode choke. 6t of RG316 would be ok on the common mode choke for modest power, 0.6mm ECW on the EFHW transformer.