LBI-38908
12
RECEIVER ALIGNMENT
Alignment of the Front End and Local Injection circuits
are not required because band-pass filters are employed in
the ORION wide-band synthesized radio receiver.
TEST EQUIPMENT REQUIRED
• Distortion Analyzer
• AC Voltmeter
• RF Signal Generator
• Frequency Counter (403-512 MHz)
• 4-Ohm, 25-Watt Resistor
• Audio Isolation Transformer (1:1)
19A116736P1 or equivalent
Before aligning the receiver or making any
adjustments to the radio, be sure that the output
of the 9-Volt Regulator is 9.0
±
0.2 Vdc.
NOTE
ADJUSTMENT PROCEDURES
Receiver Frequency Adjustment
No receiver frequency adjustment is required.
2nd Receiver Oscillator
Using a frequency counter monitor TP5 Terminal, set
L521 for a frequency of 82.655 MHz ±200 Hz.
IF/FM Detector Alignment
1. Apply a 1000 micro volt, on-frequency test signal
modulated by 1,000 Hz with standard deviation to
antenna jack J1.
2. Connect a 4-ohm, 25-watt resistor in place of the
speaker. Connect the isolation transformer input across
the resistor. Connect the isolation transformer output
to the Distortion Analyzer (see Figure 4).
3. Adjust the VOLUME control for 15 watts output (7.75
VRMS) using the Distortion Analyzer as a voltmeter.
4. Set the output signal level of the RF signal generator so
as to obtain 12 dB SINAD at audio output.
5. Adjust coils L502, L504, L505, and L507 to obtain
minimum 12 dB SINAD.
6. Set the output signal level of the RF signal generator to
1000 microvolts.
7. Adjust L523 for maximum audio output.
8. Adjust RV501 for XTONEDEC output at ORCC to
500 mVRMS.
Figure 4 - Audio Isolation Transformer
Isolation transformer needed only if instrument cannot be isolated from ground at input terminals.
NOTE
4-OHM
LOAD
1 : 1
DISTORTION
ANALYZER
OR
AC VOLTMETER
ISOLATION
TRANSFORMER
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