GE MASTR II User Manual

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MASTRO
MAINTENANCE MANUAL
25·50 MHz, 50-WATT STATION TRANSMITTER
EXCITER
ASSEMBLY
PA
ASSEMBLY
SPECIFICATIONS *
FCC Filing Designation
Frequency Range
Power Output
Crystal Multiplication Factor
Frequency Stability
5C-ICOM with EC !COM
EC-ICOM or 5C-ICOM
2C-ICOM
Spurious and Harmonic Emission
Modulation
Audio Frequency Characteristics
Distortion
Deviation Symmetry
Maximum Frequency Spread:
(2 to 4 channels)
25-30 MHz
30-36 MHz
36-42 MHz
42-50 MHz
Full
KT-56-A, C
KT-57-A, C
Extended local control; Intermittent Duty
Extended local/DC & Tone Remote
KT-58-A, C
DC Remote/Tone Remote; Intermittent Duty
All controls; Continuous Duty
25-50 MHz
50 Watts (Adjustable from 15 to 50 Watts)
3
±0.0005% (-30°C to +60°C)
±0.0002% ( 0°C to +55°C)
±0.0002% (-30°C to +u0°C)
At least 85 dB below full rated
power output
Adjustable from 0 to ±5 kHz swing with instantaneous
modulation limiting.
Within +l dB to -3 dB of a 6-dB/octave pre-emphasis
from 300 to 3000Hz per EIA standards. Post limiter
filter per FCC and EIA.
Less than 2% (1000 Hz)
Less than 3% (300 to 3000 Hz)
0.5 kHz maximum
Specifications
l
dB
Degradation
0.16 MHz
0.32
MHz
0.20 MHz
0.40 MHz
0.24 MHz
0.47 MHz
0.28
MHZ
0.54 MHz
Duty Cycle EIA 20% Intermittent (KT-56-A, C & KT-57-A, C)
Continuous (KT-58-A, C)
RF Output Impedance 5o ohms
d'lese specifications ore intended primarily for the use of the serviceman. Refer to the appropriate Specification Sheet for the complete specifications.
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GE MASTR II Specifications

General

Channel Spacing	25 kHz
Modulation	FM
Operating Temperature	-30° C to +60° C
Frequency Range	450-512 MHz
Battery Life	N/A (Typically powered by external source)

Summary

Specifications

Power Output

Frequency Stability

Specifies frequency stability under different temperature conditions.

Spurious and Harmonic Emission

Modulation

Circuit Analysis

Exciter Circuit Analysis

Detailed analysis of the exciter's components and operation.

ICOMs

Integrated Circuit Oscillator Modules used in the exciter.

Oscillator Circuit

Explanation of the oscillator's frequency characteristics and compensation.

Compensator Circuits

Details on cold and hot end compensation circuits for frequency stability.

Audio IC

Frequency Divider IC

Phase Modulators, Amplifiers & Multipliers

Power Amplifier

Detailed description of the power amplifier assembly and its components.

Power Control Circuit

Explanation of the circuit controlling power output and temperature protection.

RF Amplifiers

Maintenance

Disassembly

PA Transistor Replacement

Step-by-step guide for replacing power amplifier RF transistors.

Alignment Procedure

Procedures for aligning the transmitter circuits.

Test Procedures

Procedures for testing transmitter performance, including power and deviation.

Troubleshooting Procedure

Systematic approach to diagnosing and resolving transmitter problems.

Schematic Diagrams

Exciter Schematic Diagram

Detailed schematic of the 25-50 MHz exciter board.

Power Amplifier Schematic Diagram

Detailed schematic of the 25-50 MHz power amplifier assembly.

Parts List and Production Changes

Parts List

Transmitter Alignment

Preliminary Checks and Adjustments

Exciter Alignment

Alignment procedure for the exciter section.

Power Amplifier Alignment

Alignment procedure for the power amplifier section.

Modulation Level Adjustment

Modulation Level Adjustment

Procedure for setting the modulation level and limiter function.

ICOM Frequency Adjustment

ICOM Frequency Adjustment

Procedure for adjusting the frequency of the ICOM modules.

Test Procedures

Power Measurement

Voice Deviation and Symmetry Testing

Tone Deviation with Channel Guard

Troubleshooting Procedure

Quick Checks

Typical DC Voltages

Audio and Oscillator Waveforms