4) A
djust “RX Freq Trim” to /- 50 Hz of LO Frequency on the Frequency Counter.
5)
Click the “Main” tab.
RX Filter Alignment and Sensitivity
6) Set signal generator RF output level to -118 dBm with 1.5 kHz deviation of a 1 kHz tone.
7) Connect the SINAD meter to Pin 6(de-emphasized output) and Pin 1(Gnd) of the RJ-12 connector.
8) Adjust C102, C108, C115 and C121 to maximize SINAD. The signal generator RF output level can be temporarily set
higher if needed to see the demodulated 1 kHz sine wave. Unit should obtain at least -118 dBm (-120 dBm typically)
sensitivity for a 12 dB SINAD when tuned up is completed.
2
nd
IF Local Oscillator Filter Distortion
9) Modulate RX carrier frequency with square wave of 400 Hz. Raise the signal generator RF Output Level amplitude to
about -110 dBm.
10) Click the
“Alignment” tab, the “Miscellaneous” button, and then the “IF Trim” radio button. Connect scope probe to the
Pin 5(flat output port) and Pin 1(Gnd) of the RJ-12 connector. Jumper J308 should be connecting pins 2 and 3 to get
the RX signal. These are the lower two pins as seen on the picture below. This is the factory default.
J308
Default Position
