K-Band Mixer Diode Voltage Adjustment - Decatur Electronics SI-2 Technical Manual

K-Band Mixer Diode Voltage Adjustment

Required equipment:
(1) Digital volt meter (DVM)
(2) 12VDC power supply
(3) Modified 1/4" nut driver for the SI-2 and 3/16" nut driver for the SI Arcade (See below.)
Diode Voltage Adjustment
Cut off the handle of the nut driver to expose the hollow shaft. Grind the tip of the nut driver to reduce its
diameter to 0.275".
(1) Remove the turnstile horn lens assembly from the can, leaving the cable harness and ground wire con-
nected.
(2) Turn the radar on and activate the antenna.
(3) Place the leads of the DVM across the mixer diode.
(4) Loosen the locking nut.
(5) If you are adjusting the SI-2, adjust turnstile-tuning screw, so the voltage is minimized. If you are adjusting
the SI-Arcade, adjust the voltage to .150VDC (150mVDC).
(6) Simultaneously tighten the locking nut and adjust the tuning screw to maintain the screw at the required
low voltage point.
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