SEA 157S User manual

SEA COM CORPORATION.
PRELIMINARY MAINTENANCE MANUAL
VHF FM RADIOTELEPHONE & DSC CONTROLLER
MODEL SEA 157S
© Copyright 2010
SEA COM Corp.
All rights reserved.
SEA COM Corp.
7030 220th St. SW
Mountlake Terrace, Washington 98043
TEL: [phone]
FAX: [phone]
101
019A

**IMPORTANT**
NOTICE TO INSTALLERS
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NOTE: The safe compass distance for this equipment (As defined in
Paragraph 29 of IEC Publication 92-101, Third Edition):
SEA 157S VHF FM TRANSCEIVER/DSC CONTROLLER = 2.0 meters
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TABLE OF CONTENTS
PAGE
1. INTRODUCTION............................................1-1
2. SEA 157S SPECIFICATIONS.................................2-1
2.1 General............................................2-1
2.2 Transmitter........................................2-1
2.3 Receiver...........................................2-2
2.4 Mechanical.........................................2-2
2.5 DSC controller.....................................2-3
3. OPERATING THE SEA 157S..................................3-1
3.1 Front Panel Controls...............................3-1
3.2 Display............................................3-1
3.3 Push To Talk.......................................3-1
3.4 Radiotelephone Operating System Functions..........3-2
3.5 Digital Selective Calling Operating System.........3-7
3.6 Using Test, Calibration and Diagnostic Utilities...3-13
3.7 USA Frequency List.................................3-14
3.8 International Channel list.........................3-15
3.9 Weather Channel list...............................3-16
4. INSTALLATION............................................4-1
4.1 Preliminary Check..................................4-1
4.2 Shelf or Overhead Mounting.........................4-1
4.3 Bulkhead Mounting..................................4-1
4.4 Power Supply Wiring................................4-1
4.5 Antenna Wiring.....................................4-1
4.6 External Speaker Wiring............................4-2
4-7 NMEA 0183 and RS232 Wiring.........................4-2
5. THEORY OF OPERATION.....................................5-1
5.1 Frequency Synthesizer..............................5-1
5.2 Modulation Circuit.................................5-2
5.3 Main Receiver......................................5-2
5.4 Transmit Amplifier Chain...........................5-5
5.5 Antenna Interface Circuits.........................5-5
5.6 Automatic RF Power Control (APC) and TX Logic......5-6
5.7 TX Logic Detector..................................5-6
5.8 Power and Audio Circuits...........................5-6
5.9 Microcomputer Circuitry............................5-7
5.10 Keypad/Keypad Lighting.............................5-8
5.11 Display/Display Lighting...........................5-8
6. MAINTENANCE.............................................6-1
6.1 General............................................6-1
6.2 Recommended Test Equipment.........................6-1
6.3 Basic Performance Tests............................6-2
6.4 Transmitter Alignment..............................6-3
6.5 Receiver alignment.................................6-6
7. Block Diagram/Schematics............................7-1/7-9

LIST OF FIGURES
FIG. ___________________DESCRIPTION___________________ Page
2.1 Front view of SEA 157S.............................2-4
2.2 Rear view of SEA 157S..............................2-5
4.1 Outline Dimensions of SEA 157S.....................4-3
4.2 Flush Mount Kit Drill Template for SEA 157S........4-4
6.1 Transmitter test setup.............................6-7
6.2 Receiver test setup................................6-8
7.1 Functional Block Diagram...........................7-1
7.2.1 RF Mainboard Schematic Diagram, Sheet 1............7-2
7.2.2 RF Mainboard Schematic Diagram, Sheet 2............7-2
7.2.3 RF Mainboard Schematic Diagram, Sheet 3............7-4
7.2.4 RF Mainboard Schematic Diagram, Sheet 4............7-5
7.2.5 RF Mainboard Schematic Diagram, Sheet 5............7-6
7.3 VCO Board Schematic Diagram........................7-7
7.4 Receiver Board Schematic Diagram...................7-7
7.5.1 CPU Mezzanine Board Schematic Diagram, Sheet 1.....7-8
7.5.2 DSP Mezzanine Board Schematic Diagram, Sheet 2.....7-8
7.6 Channel 70 Circuit Board Schematic Diagram.........7-9

1 INTRODUCTION
This SEA 157S Service Manual provides detailed technical
information for use by installation and service technicians.
General operating instructions and installation drill
templates are provided in the SEA 157S Operator's Handbook
(SEA P/N OPR-157S) supplied with each SEA 157S.
SEA COM Corp. continually strives to improve its products so
that we may better serve our customers. SEA COM reserves the
right to make changes to SEA 157S specifications, hardware,
software or documentation at any time without notice.
SEA COM's Marine Service Department is always available to
provide additional help with technical difficulties.
Please call SEA COM's Service Department to obtain a Return
Authorization Number (RA#) before shipping equipment to SEA
COM.
Service parts are available through SEA COM Marine
Sales/Service Departments. Please order parts using SEA part
numbers found in Section 8.
1-1

2 SEA 157S SPECIFICATIONS:
2.1 GENERAL
FREQUENCY RANGE: TX 155-159MHz
US TX 156.0-157.5MHz
RX 155-164MHz
FREQUENCY RESOLUTION: 12.5kHz
CHANNELS: All US, Canadian, Int'l
plus 10 WX
POWER REQUIREMENT: Voltage: 13.6Vdc, +/-15%
Negative Ground
CURRENT: Max TX: 5.5 Amps (25W)
1.0 Amps (1W)
RX (STBY):0.4 Amps
RX (Max): 1.0 Amps
FUSES: 7.5 Amps (External)
2.2 TRANSMITTER
EMISSION: 16K0F3E & 11K2F3E (Voice)
13K5G2D (DSC)
11K2F2D (GMSK)
POWER OUTPUT: 25W, 1W into 50 ohms
SPURIOUS EMISSIONS: -80 dB or better
SPURIOUS RADIATION: Complies with FCC 80.211(f)
AUDIO HARMONIC DISTORTION: 10% max.
AUDIO FREQUENCY RESPONSE: +1,-3dB of +6 dB/octave
Pre-emphasis 300-3000 Hz
HUM AND NOISE: 50 dB
FREQUENCY DEVIATION: 5kHz max. peak
CARRIER FREQUENCY STABILITY: ±5ppm, -30 to +60 C
TRANSMITTER ATTACK TIME: <100 milliseconds
2-1

2.3 RECEIVER
FREQUENCY RANGE: Simplex 155-159MHz
Semi-duplex 159-164MHz
INTERMEDIATE FREQUENCIES: 21.4MHz, 450kHz
SENSITIVITY: <0.3uV for 12 dB SINAD
AUDIO FREQUENCY RESPONSE: Within +1,-3 dB of 6 dB per
octave de-emphasis from 300-
3000Hz
AUDIO OUTPUT: 4W at less than 10%
distortion into external
4 ohm load. 2W internal
HUM AND NOISE: Unsquelched: -45dB
Squelched: -55dB
ADJACENT CHANNEL SELECTIVITY: -80dB @ 25kHz
-85dB @ >50kHz
SPURIOUS EMISSION, RADIATION: Complies with FCC
SQUELCH SENSITIVITY: Threshold: .2uV max.
Tight: max 10dB above
reference sensitivity
RECEIVER ATTACK TIME: Less than 100mSec
RECEIVER CLOSING TIME: 100msec typical
250mSec max
SCAN RATE: Max 10 channels/second
MODULATION ACCEPTANCE: 6kHz minimum
7kHz typical
2.4 MECHANICAL
DIMENSIONS: (HEIGHT-WIDTH-DEPTH)
In: 3.6 x 9.6 x 3.1
mm: 91 x 244 x 79
WEIGHT: Lbs: 3.0
Kgs: 1.4
2-2

2.5 SEA 157S VHF DIGITAL SELECTIVE CALLING CONTROLLER
The VHF Digital Selective Calling Controller
incorporated into the SEA 157S VHF Radiotelephone has
been designed to comply with all FCC regulations given
in 47 CFR 80.225. This encompasses compliance with the
following documents, which are included for reference:
80.225(a) ITU-R Recommendation M.493-9 Class D
80.225(a) RTCM Paper 56-95/SC101-STD
2-3

Page 2-4
SEA 157S
Front View
Figure 2.1

Page 2-5 Figure 2.2
SEA 157S
Rear View