(Nov 19 2012)

NE334-S01. Directly from drain to the source ground plane is a RC link 10pF/100 ohms. The wire from the drain to the output side is routed through a small ferrite tube that adds a resistive loss of 3 ohms on 144 MHz and 11 ohms on 1296 MHz.

The drain goes to a phase inverter with 2x3 turns on a BD 3.5/1.3/6-4S2 ferrite tube. The midpoint is not grounded but connected to ground through a 40 pF trimmer. This trimmer is used to set the phase correctly to get a deep minimum in the reverse signal. DC is applied at the midpoint through an inductor. The output is tuned with a PI-filter.

The drain voltage is set with a potentiometer followed by an emitter follower to 1.29 V. The source resistance is set to 49 ohms with another potentiometer this gives a current of 9.8 mA through the transistor.

NE334-S01. Input impedance and forward gain.

NE334-S01. Output impedance and reverse isolation.