User's Manual

TABLE OF CONTENTS SST-442
TOPIC PAGE
IMPORTANT MAINTENANCE/REPAIR INFORMATION .. 1
SPECIFICATIONS
GENERAL......................................................................... 2
CONTROLS ...................................................................... 2
TRANSMITTER................................................................. 2
RECEIVER........................................................................ 3
BATTERY ......................................................................... 3
INTRODUCTION
GENERAL......................................................................... 4
Model Identification ..................................................... 4
FCC REGULATIONS
Licensing..................................................................... 4
Safety Standards......................................................... 4
BATTERY CARE
CHARGING....................................................................... 5
PRECAUTIONS ................................................................ 5
BATTERY REPLACEMENT.............................................. 5
Fig. 1 Battery Replacement......................................... 5
BATTERY MAINTENANCE............................................... 6
BATTERY CONDITIONING .............................................. 6
OPERATION
DESCRIPTION OF CONTROLS AND CONNECTORS..... 7
Fig. 2 Controls and Accessory Connectors.................. 7
RADIO OPERATION
On-Off/Volume ............................................................ 8
Receive....................................................................... 8
Selective Signaling Squelch ........................................ 8
Monitor........................................................................ 8
Battery Saver .............................................................. 8
Transmit...................................................................... 8
Channel Selection ....................................................... 8
WHAT THE RADIO TONES MEAN
Power On/Self Check “OK........................................... 9
Error Tones ................................................................. 9
Channel Select............................................................ 9
Tone Squelch.............................................................. 9
Recharge Battery Alert ................................................ 9
OPTIONAL RADIO TONES
Receiver Squelch Tone ............................................... 9
Busy Channel Inhibit ................................................... 9
Transmitter Time Out .................................................. 9
BELT CLIP INSTALLATION.............................................. 9
TROUBLESHOOTING
General ..................................................................... 10
Battery ...................................................................... 10
Error Tones ............................................................... 10
Tone Coded Squelch................................................. 10
PROGRAMMING THE RADIO
PTT (PUSH-TO-TALK) PROGRAMMING
Fig. 3 Placing the Radio in Program / Readout Mode 11
Reading Out a Radio Channel’s Content................... 11
PTT Programming the Radio..................................... 12
Return To Normal Operation ..................................... 12
PTT Programming Mistakes...................................... 12
Table 1 – PTT Programming Frequency Table.......... 13
Table 2 – Quiet Call Codes and Frequencies ............ 13
COMPUTER SOFTWARE COPYRIGHTS ...................... 13
PC COMPUTER PROGRAMMING ................................. 13
Programmable Features............................................ 14
Description of Features ............................................. 15
TOPIC PAGE
THEORY OF OPERATION
INTRODUCTION .............................................................16
POWER SUPPLY AND VOLTAGE DISTRIBUTION........ 16
Power Strobe.............................................................16
Low Battery Voltage Detection...................................16
REFERENCE OSCILLATOR ...........................................16
SYNTHESIZER ..............................................................16
Pin Numbers..............................................................16
Prescaler Divider / Synthesizer Controller..................16
VCO / Buffer Amplifiers .............................................17
Oscillator Modulation .................................................17
DIGITAL POTENTIOMETERS......................................... 17
RECEIVER...................................................................... 17
RF Amplifier...............................................................17
1st Mixer....................................................................18
FM Receiver Subsystem............................................ 18
Voice / Tone Conditioning in Receiver Mode .............18
Voice Band ................................................................ 18
Sub-Audible............................................................... 18
Audio Amplifier ..........................................................18
ANTENNA SWITCHING / LOW-PASS FILTER............... 19
TRANSMITTER ...............................................................19
Keying ....................................................................... 19
+VTX Supply..............................................................19
Power Amplifier .........................................................19
Voice/Tone Conditioning in Transmit Mode ...............19
Voice Band ................................................................ 19
Sub-Audible............................................................... 19
MICROCONTROLLER .................................................... 20
ALIGNMENT PROCEDURE
RECOMMENDED TEST EQUIPMENT............................ 21
RADIO PREPARATION...................................................21
REFERENCE FREQUENCY ...........................................21
MODULATION BALANCE ............................................... 22
TRANSMITTER TONE DEVIATION ................................22
TRANSMITTER VOICE DEVIATION...............................22
RECEIVER SENSITIVITY AND SQUELCH.....................22
RECEIVER NOISE SQUELCH........................................23
SYNTHESIZER ............................................................... 23
VOLTAGE CHART
Measurement Conditions................................................. 24
SST-442 Voltages ........................................................... 24
PARTS LIST
SCHEMATIC REFERENCE PARTS LIST ....................... 27
CASE ASSEMBLY PARTS LIST ..................................... 33
SCHEMATIC AND PART PLACEMENT DRAWINGS
TOP SIDE PART PLACEMENT....................................... 35
BOTTOM SIDE PART PLACEMENT............................... 36
SCHEMATIC – UHF RF ..................................................37
SCHEMATIC – Signal Processing ...................................38