В даташите на трансформатор есть параметр DC Current 30 mA
Что это значит

In some applications there is a need to pass a relatively high DC current through the primary winding. In this case, the transformer core may saturate resulting in reduced transformer bandwidth and power handling capability. Mini-Circuits TH series of transformers are designed to handle up to 100 mA in the primary winding without appreciable saturation and change in RF characteristics.
Transformer core saturation is influenced by (1) DC current through the winding, (2) RF input power, and (3) frequency of operation.

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