bare_minimum_z-bridge

Bare Minimum Z-Bridge

Minimalist Z-bridge for measuring and adjustment of impedance or impedance match.

Make this transformer with 10 turns, trifilar, on a T37-43 core. Space the turns evenly around the core.

This transformer may be used in two ways.

1. Insert a signal at the Input, add a fixed resistor at the Resistance leg, connect your antenna and tune the input signal frequency for a voltage null on the detector leg. Use an oscilloscope or diode detector on the Detector leg.
3. Insert random noise at the input, connect a variable resistance at the Resistance leg, and your antenna at the Antenna leg. Use a receiver as the detector. Adjust the resistor for null, and read this as your antenna impedance at the receiver frequency.