SGC SG-2000 Operating Manual

SG-2000 MANUAL

SG-2000

1.6-30 MHz

150 Watt Output

Multi-Mission

HF SSB

Transceiver

Operations and Programming Manual

Revised: Oct, 1995

CAUTION: Carefully read the "Quick Start" (yellow card

packed with your radio) and the "Operating the SG-2000" section
of this manual beginning on Page 41. The SG-2000 is a high
precision electronic device. Taking the time to learn all of its
capabilities will insure maximum performance, reliability and
enjoyment of the unit.

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SG-2000 MANUAL i

TABLE OF CONTENTS

1.0 General Description and Specifications.......................................................1

1.1 General Description of the SG-2000 ........................................1

1.2 Power Requirements .................................................................2

1.3 SG-2000 Performance Specifications .......................................2

1.4 Data Comunications ..................................................................3

1.5 Computer Control of SG-2000..................................................3

1.6 Multiple Control Head Specifications.....................................4

1.7 Dimensions and Weight............................................................4

1.8 Standard Features ......................................................................4

1.9 External Accessories..................................................................5

1.10 Internal Accessories...................................................................5

2.0 Unpacking .......................................................................................................7

3.0 History of the SG-2000 .....................................................................................8

4.0 About the SG-2000 ............................................................................................10

4.1 Receiver Signal Path ..................................................................10

4.2 Transmitter Signal Path.............................................................11

4.3 Control Circuits..........................................................................12

4.4 Control Heads.............................................................................13

4.5 SG-2000 Front Panel...................................................................13

4.6 SG-2000 Rear Panel....................................................................13

5.0 SGC Family of Control Heads........................................................................14

5.1 Remote Mobile Heads...............................................................14

5.2 PowerTalk™ and PowerTalk™ SA .........................................14

6.0 SG-2000 Software and Accessories ................................................................15

6.1 GPS Software ..............................................................................15

6.2 Oil Platform Software................................................................15

7.0 Planning for Installation .................................................................................16

7.1 Location of Power Supplies......................................................16

7.2 Control Head Placement...........................................................16

7.3 Control Head Wiring.................................................................17

7.4 External Speakers.......................................................................17

7.5 External Accessories..................................................................18

8.0 Radio Licenses ...................................................................................................19

8.1 Station Licenses ..........................................................................19

8.2 Operator Licenses ......................................................................20

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9.0 Installation .......................................................................................................21

9.1 SG-2000 Rear Panel Connections.............................................21

9.2 External Coupler Installation...................................................22

9.2 External Modem, Weatherfax and High Seas Direct™........23

9.3 Continuous Duty Ratings .........................................................23

9.4 Rack Mount Kit Installation (Part No. 52-90).........................24

9.5 Control Head Installations........................................................27

9.6 Remote Head Kit Installation (Part No. 04-12)......................27

9.7 Additional Control Heads (Part No. 04-11) ...........................28

9.8 Remote Head Cable Extension.................................................29

10.0 Power Supplies..................................................................................................30

10.1 Cabling.........................................................................................30

10.2 AC Power Supplies....................................................................31

10.3 Transformer-Rectifier Supplies................................................31

10.4 Mobile Power Supplies .............................................................32

10.5 Solar-Powered Chargers...........................................................33

11.0 Antenna Systems...............................................................................................34

11.1 Antenna Wire Size .....................................................................35

11.2 Near Vertical Incidence Skywave............................................36

11.3 Base Station and Fixed Antennas ............................................36

11.4 Antenna Feed Lines...................................................................37

11.5 Antenna Couplers......................................................................37

11.6 Mobile Antennas........................................................................38

11.7 QMS Recommended for Mobile Use.......................................39

11.8 Unconventional Mobile Antennas...........................................40

12.0 Operating the SG-2000 ..................................................................................... 41

12.1 Syntax ..........................................................................................41

12.2 Front Panel..................................................................................43

12.3 Push-Button Functions..............................................................44

12.4 Sample Entries............................................................................48

13.0 Tour of the SG-2000..........................................................................................49

13.1 Front Panel Display ...................................................................49

13.2 Front Panel Controls..................................................................52

13.3 Primary Keyboard Functions...................................................52

13.4 Shift Functions............................................................................57

13.5 Program Functions.....................................................................59

13.6 Operating Session ......................................................................59

13.7 Channel........................................................................................60

13.8 Frequency....................................................................................61

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13.9 Programming..............................................................................63

13.10 Scanning Functions....................................................................64

13.11 Changing Frequency or Channel Scan Rates.........................68

13.12 Additional Functions.................................................................69

14.0 Mobile Installation ...........................................................................................75

14.1 Shock and Vibration Mounting................................................75

14.2 Mobile Grounds .........................................................................76

14.3 Vehicular Noise Sources ...........................................................78

15.0 Marine Installation ...........................................................................................80

15.1 Marine Radio Mounting ...........................................................80

15.2 Marine Ground Systems ...........................................................80

15.3 Marine Antennas........................................................................82

15.4 High Seas Direct™ Connections..............................................82

16.0 Remote Control..................................................................................................85

16.1 Extension of Control Head Wiring..........................................85

16.2 Short Haul Modems/Auto-Answer Devices.........................86

16.3 Line of Demarcation ..................................................................86

16.4 Auto-Answer Devices ...............................................................87

16.5 Computer Networks - Serial Control......................................87

17.0 External Software..............................................................................................88

17.1 RS-232 Serial Control Software................................................88

17.2 RS-232 Software Installation.....................................................89

17.3 Main Menu Display...................................................................92

17.4 Main Menu Operations.............................................................93

17.5 Menu 2 Operations ....................................................................95

17.6 Programming Functions ...........................................................96

17.7 PC Cable Assembly....................................................................98

18.0 ALE and Adaptive Controllers .......................................................................100

18.1 SG-2000 Serial Port Operation..................................................101

18.2 Serial Communication Protocol...............................................102

18.3 ALE Controller-Command Examples.....................................103

18.4 Recall a Selected SG-2000 Memory Into Active Use.............103

18.5 SG-2000 Connections to ALE Controller ................................104

19.0 Accessories 106

19.1 Exsel-100 Selective Calling System..........................................106

19.2 Telerex™ ARQ/FEC/SELFEC System...................................107

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20.0 Answers to Frequently Asked Questions.....................................................108

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21.0 Technical Reference..........................................................................................110

21.1 Squelch Scale Recalibration ......................................................110

21.2 SG-2000 Microprocessor Reset Procedure..............................110

21.3 Emergency Calling.....................................................................111

21.4 Basic Tune-up Procedure (Alignment) ...................................112

21.5 AM Filter Bypass........................................................................113

21.6 Oscillator and Filter Operation................................................113

21.7 Microprocessor Assembly ........................................................115

21.8 VCO's...........................................................................................115

21.9 PLL's.............................................................................................115

21.10 Serial Logic Switches .................................................................116

21.11 Tone Generator...........................................................................116

21.12 Oven Switch................................................................................116

21.13 Alarm Generator ........................................................................116

21.14 Master Oscillator with Oven ....................................................117

21.15 Crystal Oven...............................................................................117

21.16 Output Low Pass Filters............................................................118

21.17 Automatic Level Control ..........................................................118

21.18 Modulation Characteristics, AFR ............................................118

21.19 Modulation Characteristics, PEP Limiting.............................119

21.20 SG-2000 Performance Measurements .....................................121

22.0 Trouble Shooting ..............................................................................................127

22.1 Dysfunctions...............................................................................127

22.2 Scanning in One Direction Only..............................................128

23.0 Test Procedures..................................................................................................129

23.1 Exciter Testing Procedures .......................................................129

23.2 LPA Testing Procedures............................................................156

23.3 Display Section Testing Procedures........................................163

23.4 Head CPU and Main CPU Testing Procedures.....................171

23.5 Final Assembly Testing Procedures........................................178

24.0 Schematic Reference Section ..........................................................................180

INDEX .......................................................................................................................210

Appendix A, Frequency List .......................................................................................A-1

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SG-2000 MANUAL 1

1.0 General Description and Specifications

This section includes a short description of the features of the SG-2000 Transceiver
along with its specifications. This manual includes information useful for the SG-2000,
the SG-2000 SlimPak, and the Military version (PRC-2250 MIL).

1.1 General Description of SG-2000

Model SG-2000
Channels 100 channels field programmable
644 factory programmed ITU voice and data channels
Scan channels Up to 100 channels programmable in 6 groups of 10

channels each
Scan frequency In 0.1, 0.5, 1, 3, and 5 KHz steps
Scan frequency
range Full HF range or a selected range of frequencies
Scan dwell time Adjustable from .1 to 40 seconds
Frequency scan dwell: .1 to 1 second
Channel dwell time: .2 to 40 seconds
Transmitter
frequency range 1.6 to 30 MHz
Receiver frequency
range 1600 KHz to 30 MHz (500 KHz - 30 MHz Optional)
Frequency stability ±10 Hz
Frequency resolution 100 Hz
Modes A3A, A3H, A3J and CW in LSB and USB, True AM detector in

receive mode. Data modes supported by external controllers.
Protection Fully protected against damage due to battery reversal, over

voltage, or antenna fault (open or short).
Display LCD for frequency or channel with annunciators of all

functions and modes, 20-segment bar meter, and time or

date
Metering S-meter in RX mode, forward power or VSWR in TX mode
AGC Fast attack slow release in Voice mode. Extremely fast attack

fast release in telex and ALE modes.
Keypad 21 push-buttons include power, up/down, all functions, and

numeric entry

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SG-2000 MANUAL 2

Alarm generator Programmed for standard ITU and CCIR alarm on

emergency frequency 2182 KHz or can be broadcast on any

frequency. Having to press two push-buttons simul-

taneously to activate transmitter prevents accidental alarm.

Operating
temperature -45° to 85° C
Full specification
temperature -30° to 60° C
Approvals FCC type accepted, parts 80, 87 and 90. DOC and

CEPT(pending). Meets CCIR specification for receiver and

transmitter* (see page 5)
Color Black
Front panel Splash proof, removable and may be mounted remotely

1.2 Transceiver Power Requirements

Nominal 13.6 VDC; 0.8A RX, 16A TX (voice)
Full specification
compliance 11.5 VDC
Full operation 10.5 to 18.0 VDC
Current drain when
radio off:
STBY mode,
Oven on; 430 mA
oven off; 80 mA

1.3 SG-2000 Performance Specifications

RECEIVER SPECIFICATIONS
Sensitivity .5µV produces .5W of audio with 10dB SNR (Signal to

noise ratio may vary from 7 to 16 dB at nominal .5 µV

input)
Selectivity 2.4 KHz at -6 dB; 4 KHz at -60 dB shape factor better

than 2:1)
Intermodulation +86 dB (CCIR specification)
Blocking +100 dB (CCIR specification)
Transmodulation + 95 dB (CCIR specification)
Image and IF
rejection +90 dB
Audio output 4W with less than 10% distortion
Audio distortion Less than 5% at 3W

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SG-2000 MANUAL 3

AGC response Less than 5dB variation at the output for 5µVolt to 1

Volt RMS at the receiver input
Clarifier range ±600 Hz in 100 Hz steps
Receiver protection Up to 50 Volt RMS at the receiver input
Squelch Voice operated with syllabic detection — adjustable

threshold
Speaker Internal ( on removable front panel)
TRANSMITTER SPECIFICATIONS

Power output in
50 ohms 150 watts* PEP ( +0dB to -.5 dB) (see page 5)
Power output
reduction To less than 50 watts PEP
Maximum stress
power output 225 watts CW*** (see page 5)
Sideband suppression Better than -50 dB at 1400 Hz
Harmonic
suppression Better than -63 dB** (see page 5)
Carrier suppression (A3J) Better than -55 dB
Carrier level (A3H) -3 dB
(A3A) -16 dB
Noise suppression Better than -60 dB
Distortion
(third order) Better than -32 dB at 135W PEP
Audio response Flat within 6 dB between 350 & 2400 Hz
VSWR protection For 4:1 VSWR, power output will reduce below 50

watts PEP
Thermal protection For 80°C power output will reduce below 50 watts PEP

1.4 Data Communications

Ready and compatible RTTY, ARQ, FEC, PACKET and telegraphy
Receive/transmit
switching time 10 mS nominal
AFSK input/output
impedance 600?
AFSK input level Minimum required 100 mV RMS, 2V RMS maximum
AFSK output level 240mV RMS at .5µV, maximum 1V RMS

1.5 Computer Control of SG-2000

Input/Output RS 232

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SG-2000 MANUAL 4

Access and recall Of all transceiver functions except audio
Software SG-2000 for DOS (Supplied with C language source

code)
System software DOS Ver. 3.0 or greater for IBM and compatibles (user

supplied)

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SG-2000 MANUAL 5

1.6 Multiple Control Head Specifications

Local One controller mounted to the radio (except SlimPak)
Remote Up to 50 meters away from the radio (10 wires)
Intercom On all remotes
Maximum number of
controllers 8 (Total of control heads and computers not to exceed 8)
Telephone remote Through standard telephone line and modem with

telecommunication software and SGC-RS-232 software

1.7 Dimensions and Weight

Overall Dimensions 11.7 (H) x 25.4 (W) x 38 (L) cm 4.75 in. (H) x 10 (W) x 15

(L) inches (SlimPak 1" less in height)
Weight 5.4 kg (12 lbs)

1.8 Standard Features

• Full remote control, up to 8 stations

• Upper or lower sideband select

• A3A, A3H and A3J select

• Emergency 2182 direct select (Standard Head only)

• Voice or Telerex (narrow band) filter select

• CW side tone oscillator, CW with break-in

• Alarm Generator

• Speaker on/off, rear panel audio I/O port for modems, Weatherfax

• Headset/handset driver separate from speaker

• Carbon or dynamic microphone select switch

• Squelch on/off and level set

• Coupler tuned indicator

• 20 dB receive attenuator

• Transmitter power level set (50 or 150W)

• Transmitter over temperature indication and thermal protection

• Receive S-meter and transmit forward power or SWR meter display

• Time of day or date display

• Radio on/off timer

• Intercom with all stations or private channel select

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SG-2000 MANUAL 6

1.9 External Accessories

• Marine antennas

• Vehicular antennas

• Whip antenna in 8, 23, 28 or 35 ft. lengths

• SG-103 broadband antenna, 2-28 MHz

• SG-103-T tactical broadband antenna, 2-28 MHz

• Dipole antenna for 1,2 & 3 specified frequencies

• Field adjustable dipole antenna

• SGC Portamast

• SG-230 150 Watt MicroProcessor controlled antenna coupler

• SG-230 Pro 150 Watt MicroProcessor controlled antenna coupler

• SG-235 500 Watt MicroProcessor controlled antenna coupler

• PS-30 power supply for base station (unregulated)

• PS-35 power supply for base station (regulated)

• Standard mounting tray

• Shock mounting tray for high vibration installations

• Battery cable

• External speaker

• CW telegraphy key

• Dynamic desk and noise canceling fist microphone

• Military handset (waterproof, dustproof, shock-proof)

• Telephone handset

• Tel-Two phone patch

• Linear power amplifiers, 500 & 1000 watts output

• Front panel customizing

• TELEREX ARQ, FEC and PACKET systems

• ALE adaptive controller

1.10 Internal Accessories

• High power CW continuous fan kit

• ALE (Automatic Link Establishment) AGC switching (Specify at time
of order)

• Special Software options: Hong Kong, France (and Territories), Oil
Platform

Notes: * CFT8DK SG-2000 (1.8 to 26 MHz international radio marine bands)

** For international marine bands

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SG-2000 MANUAL 7

*** Under ambient temperature and normal load conditions

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SG-2000 MANUAL 8

DO NOT ATTEMPT TO TRANSMIT UNTIL THE

RADIOTELEPHONE IS WARMED UP FOR AT

LEAST TEN MINUTES.

The crystals that control the operating frequency are contained in a precision oven
that requires 10 minutes to rise to the correct temperature. Transmitting before the

10 minute warm-up period has elapsed may cause a violation of FCC regulations.

Precautions:

1. Operating and installation personnel must observe all applicable safety
regulations at all times. Do not operate unit without covers in place with power on.
Under certain conditions, dangerous electrical voltages may exist. To avoid injuries,
always confirm removal of power and discharge and ground all circuits before
touching them.

2. Do not service or adjust equipment when alone. Under no circumstances
should you reach into live equipment for the purposes of adjustment or servicing
unless there is someone else present who is capable of rendering aid.

3. Personnel working with or near AC power sources, power supplies and high
power radio equipment should be familiar with modern first aid techniques and
resuscitation.

4. When servicing, observe static discharge precautions to avoid damage to
microprocessors and solid state devices.

5. When servicing multiple control head installations, disconnect all remote
heads at J-503 on the rear panel of SG-2000 to prevent other personnel from
keying the transmitter during servicing.

SGC reserves the right to change specifications without notice.

2.0 Unpacking

The standard packaging for an SG-2000, the cardboard box and packing materials,
should be retained for future use should the radio need to be shipped elsewhere.

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SG-2000 MANUAL 9

Please note that the radio arrived in a polyethylene bag which includes the instruction
manual, warranty registration card and a quick reference card. Information on use of
AT&T High Seas services is also provided for your convenience. The plastic bag
protects the unit from dust and moisture when shipping. If there is condensation on the
inside of the polyethylene bag because the radio was subjected to extreme change of
temperature during shipment, please leave the plastic covering on the radio until it has
come up to ambient temperature and the condensation has evaporated.

You will notice a piece of foam rubber on the face plate of the radio, held in place with
tape. It is designed to protect the plastic face plate of the LCD. Whenever you are
shipping an SG-2000, it is good practice to secure a cover over the LCD. Small scratches
in the face plate of the LCD may be removed with Plexiglas™ cleaner such as is used to
clean aircraft windows.

The SG-2000 should be closely inspected upon arrival. As the units leave the SGC
factory, they are in perfect operating condition. Should you notice any bent sheet
metal, or flecks of paint in the shipping box, you may assume that the radio has taken a
hard shock somewhere in shipping.

The radio will usually continue to operate, even if subjected to abuse in shipping, but
please make sure that if you notice any shipping damage, you file a damage report
immediately with the carrier.

In the unlikely event that your unit has been damaged in shipping, your dealer can
instruct you on how to handle servicing or replacing the unit. If your dealer does not
know the proper procedure, you may contact SGC directly.

SGC provides a complete five-year parts and labor guarantee. However, this guarantee
does not apply to radios which are used in para-military and military operations, as
combat conditions are specifically excluded from our guarantee.

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SG-2000 MANUAL 10

3.0 History of the SG-2000

The SG-2000 is a high performance, microprocessor (computer) controlled multi­mission HF SSB radio designed to meet the needs of marine, commercial, para-military,
and amateur radio users through the year 2000 and beyond.

The SG-2000's heritage includes the SG-705, the world's smallest commercial HF SSB,
the SG-715 waterproof manpack radio, and the SG-712 EX-11 which has been proven in
commercial and military applications in all regions of the world.

The SG-2000 also benefits from SGC's expertise in microprocessor design, developed as
the company evolved its line of fully automatic antenna couplers. SGC's fully
automatic antenna couplers have been available since 1975 and the current
computerized SG-230 series of couplers has been continuously upgraded to maintain
technical dominance through software enhancements.

The SG-2000 was conceived by SGC President Pierre Goral and the SGC Engineering
staff to meet an emerging need in HF communications for a relatively low cost, highly
reliable yet flexible communications platform which would be suited to multiple
control- point operation and would allow complete computer control if desired.

This was done after a careful study of emerging HF radio technology in the military and
government sector and with an eye to providing the users of SGC equipment with the
highest level of flexibility, not only today but in the future as well.

It was clear from the SGC analysis that to an increasing degree, personal computers
would be integrated into mobile, fixed, and sea going radio operations. In addition, a
whole new field called Adaptive Controllers was being developed for government and
military use.

The SG-2000 design project became an all-consuming effort among the team members
who studied all available information in order to provide a radio which would meet
modern communications needs. The process was to collect and analyze all available
trend information, review not only cutting edge but projected technology, and then
build the radio that would meet all of these needs.

It is interesting to note the design team's criteria:

• The ideal radio would weigh as little as possible, under 6 kilograms would be
ideal. The radio would need to operate from any location. This meant telephone
line control for control at distances of several thousand miles, or by hard wire

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SG-2000 MANUAL 11

control for local use at short to moderate distances.

• This radio would need to be controllable by a computer or its own control heads
and it would have to support control from up to eight locations all at the same
time. It would also be nice if the radio could be directed through a local area
network with one computer on the network operating as a gateway.

• In addition, the eight locations would have to be connected via an intercom, the
radio would need to be of high physical strength, and would be able to operate
over extremes of temperature and humidity.

The SG-2000 would also have to meet exacting performance standards for frequency
stability and for speed of operations in order to accommodate some of the more exotic
demands of the para-military and military markets.

The result of the design effort is the SG-2000, the world's first truly computer-directed
civilian radio. Many of the attributes of the SG-2000 can be found in very expensive
military units, some costing 10 times the price of an SG-2000 and not generally available
to the public.

In 1992, SGC introduced a ruggedized version of the SG-2000 designed for para-military
use called the PRC-2250 MIL. This radio features many SG-2000 options ordered by
(para) military organizations. It is finished in an olive drab color and comes with a
military type shock mount with a waterproof handset standard, which distinguishes it
from the SG-2000 in appearance.

In 1994, SGC introduced a SlimPak version. The SlimPak has all the features of the SG­2000 and uses the same control head; yet the main unit measures a full 1 inch less in
height, enabling placement in much tighter quarters.

In 1995, SGC introduced a new model of the SG-2000 control head called the
PowerTalk™ that incorporates ADSP™ and SNS™ noise reduction and noise filtering
capabilities.

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SG-2000 MANUAL 12

4.0 About the SG-2000

The basic SG-2000 is really two units, which may be easily separated. One unit is what
is called the Radio or RF unit. This contains the receiver and the transmitter's exciter
and linear power amplifier modules. In addition, it contains the SG-2000's main
microprocessor.

The second unit, normally supplied attached to the radio unit, is called the control head.
In it are audio amplifiers, the radio's frequency and channel displays, a keyboard to
control radio functions and another microprocessor which "talks" to the main radio
unit.

Audio wiring at 600 ohms plus

RS-422 (9600 baud) Serial Bus

SG-2000 RF Unit

To additional heads
(8 maximum)

Control Head Control Head

RS-232 (9600 baud)
Serial Port for
computer

One control head may be attached to
the SG-2000 RF unit. Up to seven
others may be located up to 50 meters
away from the RF unit using 10-conductor
cable.

4.1 Receiver Signal Path

The receiver section, located in the main radio unit, features signal up conversion (from
82 to 88 MHz) to achieve maximum image rejection and to allow wide band processing
of signals. Then the signal is converted down to 10.7 MHz where an extraordinarily
sharp crystal filter removes all unwanted signals, including strong unwanted signals
which have not been eliminated by the 82-88 MHz filters.

The 10.7 MHz signal is further amplified and is then decoded by one of the two
detectors in the radio. For single sideband, CW (Morse Code), and data operations, a
product detector is used. For AM, the SG-2000 provides one of the few "true AM"
detectors available today. This provides for extremely clear reception and excellent

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capture of signals in all modes.

SG-2000 MANUAL 13

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SG-2000 MANUAL 14

Once amplified to a standard level, the audio is sent to a jack on the back of the SG-2000
which allows for connection to a control head. In the control heads, the audio signal is
further amplified and processed.

A syllabic squelch circuit (which was pioneered by SGC in 1976) is used to turn off the
noise coming out of the speaker in the event that a signal is not being received.

The next step is a digital gate which controls the volume of the receiver by very rapidly
sampling the signal and passing only a certain number of samples — a number which
varies by the setting of the volume control on the front panel of the radio. Naturally,
this happens at speeds which you can not hear, so your ear hears smooth control of the
volume function.

4.2 Transmitter Signal Path

Pressing the push to talk button grounds the push-to-talk line, placing the SG-2000 in
the transmit mode. At the same time, the sound of your voice is shaped by an audio
amplifier in the control head. This is brought up to a standard level to be sent out the
transmit audio bus.

This line leaves the control head via the 10-conductor control head cable and returns to
the SG-2000 RF unit via the rear panel connector where the head plugs into the rear
panel of the radio.

Inside the radio, the audio signal is shaped and amplified. It is turned into an AM
signal which is then processed to remove the desired amount of carrier. This is
accomplished by a balanced modulator. In the single sideband mode, all of the carrier
is removed. If required, the carrier is reinserted for other modes.

In the AME (AM Equivalent) mode, 40-50 W of the carrier is reinserted. And if you are
operating in the A3A mode which is used for certain kinds of commercial radio work,
then you put back about 1/8th of the carrier, leaving just enough of the signal to act as
a "pilot carrier" for specialized receivers.

Next, the signal is amplified and passed through a crystal filter, where one sideband is
removed. This is done by offsetting the transmit frequency slightly. On one side of the
filter slope, the upper sideband is removed, while offsetting on the other side of the 10.7
MHz filter will remove the lower sideband.

When you are in the single sideband mode, you have now developed either the desired
upper or lower sideband filter at this point. From here on, the amplifiers which will be
processing the signal are called "linear amplifiers" because if they are not linear, they
will distort the signal, just like a non-linear audio amplifier would distort a signal on
your home stereo.

The 10.7 MHz single sideband signal is then converted up to 82-88 MHz, where
harmonics are eliminated by the helical filter. The output of the 82-88 MHz filter is

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SG-2000 MANUAL 15

mixed with the correct frequency developed by the synthesizer and is then amplified at
the operating frequency.

This amplification process involves several steps: a pre-driver, a driver, and a final
amplifier section which utilizes a splitter - combiner circuit

The pre-driver and the driver sections are very straight-forward in design. But the final
LPA (Linear Power Amplifier) deserves special note because it is very conservatively
constructed. This amplifier is made up of four transistors. While most designers will
use only two, SGC elected to use four for reliability and peak power performance.

Controlling the LPA is a circuit called ALC (Automatic Level Control) which adjusts the
operating conditions of the final amplifier to insure its operation is linear over a wide
range of conditions.

A broad band filter network then matches the high power signal to a 50 ohm output
impedance. This is then sent to the SG-230 Smartuner (which we highly recommend) or
a broad band antenna system such as the SG-103.

4.3 Control Circuits

The SG-2000 is a microprocessor controlled radio. Each of the control heads has a
microprocessor and talks to the microprocessor in the radio unit using the RS-422
communications protocol. This means that the control head may be placed as much as
50 meters away from the radio. Although not supported by SGC, many users of the
control heads have reported success at longer distances. As with all SGC specifications,
50 meters is a conservative number.

The microprocessor control codes, which are generated when the front panel push
buttons are pushed, are sent to the microprocessor in the radio unit which return
confirmation to the control head that the instructions have been acted upon. The head
microprocessor controls the display information and functions such as setting of
volume and squelch levels.

Each of the control heads has a unique device address which allows the micro­processors in the radio unit to send information as well as establish the intercom
address of the control head.

In the event that you wish to address the microprocessors on the radio unit directly,
you may use the RS-232 serial port which is located on the rear panel of the radio.

Any number of serial ports and heads may be used, as long as the total number of
device addresses does not exceed eight. Four control heads and four computers works
as well as one control head and seven computers.

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SG-2000 MANUAL 16

For more information on controlling the SG-2000 via computer, see Section 16.5 of this
manual regarding "Computer Networks - Serial Control" and the parts of Section 17.0
dealing with RS-232 software.

4.4 Control Heads

There are several design considerations behind the SG-2000 control head which you
should know about in order to appreciate the beauty of the architecture of the radio.

Our many years of manufacturing experience have taught us the value of absolute
reliability and of the importance of easy reparability in the field. Such philosophies as
designing in a 10-conductor control cable between our radios and remote heads rather
than a fiber optic cable is one example. SGC has learned that while fiber optics are an
excellent material, they are not easily reparable in the middle of the desert or ocean.
SGC products are designed for field repair and performance where well-engineered
products dramatically become evident.

4.5 SG-2000 Front Panel

The front of the SG-2000 controls all radio functions. All of the push buttons are
rubberized to provide good tactile response and to keep the radio highly resistant to
water and dust, two of the worst enemies of electronic equipment.

The LCD which displays the frequency is the largest available on a radio of this type.
The speaker is treated to resist moisture. The speaker grill is designed to prevent direct
spray from hitting the speaker.

Because the front panel has been ruggedly built, the advantage of mounting the more
sensitive radio unit elsewhere becomes apparent.

4.6 SG-2000 Rear Panel

A series of Jacks on the back of the SG-2000 provide access to radio features and
accessories. Most of these jacks are covered by a metal "U" bracket which is held in
place by three small Phillips head machine screws. If you ever have occasion to remove
this cover, it is important that it be replaced in order to provide physical protection for
the jacks.

Under the "U" bracket, from left to right, you will find a jack to plug in one of the family
of SGC's Smartuners. The next plug (J-301) presents audio input and output lines, plus
push-to-talk control. This is where Weatherfax, data controllers (such as an SGC
Telerex™ SITOR modem), and ALE units are plugged in.

The next two jacks are for plugging in two control heads. If you are using more than
one control head, one will plug in to the right hand head plug while a multiple plug
adapter unit plugs into the left control head jack and provides for up to seven
additional head connections.

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SG-2000 MANUAL 17

The last jack, J505, is used for connecting an external speaker. This is also the most
common connection for the Weatherfax.

In addition, just to the right of the "U" bracket is an RS-232 connector for computer
control of the SG-2000 radio, as explained later in this manual.

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SG-2000 MANUAL 18

5.0 SGC Family of Control Heads

The SG-2000 comes with the standard control head described throughout this manual.
In addition, there are six other control heads to choose from. These range from the small
remote mobile heads to the new PowerTalk™ head incorporating ADSP™ and SNS™
noise reduction capabilities.

5.1 Remote Mobile Heads

The four models of the remote mobile heads are designed to be used in conjunction
with the SG-2000. They have simplified control functions and a much smaller footprint.
They include the basic version, the aircraft version, the Exsel version and the remote
mobile head with ADSP™ noise reduction.

Please contact SGC for information on any of these optional heads.

5.2 PowerTalk™

Another optional control head is our newly released PowerTalk™ head. The
PowerTalk™ head is the same size as the standard remote head but with more
versatility, including the additional benefit of state of the art noise reduction circuits to
let the user filter out unwanted noise.

Please contact SGC for information on this model.

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SG-2000 MANUAL 19

6.0 SG-2000 Software and Accessories

This section lists various software options that are available for the MicroProcessor
controlled SG-2000. In the event that you own an SG-2000 and later wish to add
different software, such as the GPS software, Oil Rig software, Hong Kong software, or
other software as may be periodically published, please be advised that there is a
software update charge if the software is retrofitted into an existing radio.

6.1 GPS Software

Effective April 1, 1992, a special edition of the SG-2000 main microprocessor software
was published to meet the needs of the oil and gas exploration industry for a radio
which would not search the international emergency frequency, 2182 KHz, when the
radio is first turned on. The special software is now standard.

In addition, the SG-2000, which was adapted to differential GPS radio location service
in January of 1992 has special cooling modifications which allow it to operate under
severe service for unlimited time. The additional cooling systems may be ordered by
users who anticipate extended key down operations, including differential GPS, ALE,
SITOR/AMTOR/RTTY, and other data modes or plan to subject the SG-2000 to
unusually warm operations (such as desert vehicle installations).

6.2 Oil Platform Software

In May 1992, special software became available for the main MicroProcessor of the SG­2000 which will allow the transmission of an emergency distress tone on all frequencies,
removing the normal limit of transmitting on only the international emergency
frequency, 2182 KHz. This was done at the request of oil exploration companies who
have been using the SG-2000 successfully in offshore oil exploration work and who are
required, because of international regulations, to both test and operate their emergency
distress beacons on frequencies in addition to the international 2 MHz band channel.
This software is now standard on the SG-2000. Press the shift function and emergency
buttons at the same time and the distress tone will be transmitted on the displayed
frequency.

Effective September 1, 1992, a special edition of the SG-2000 became available to users of
the SG-2000 in Hong Kong. Certain radio programming features are deleted in order
to meet Type Approval requirements of Hong Kong's G.P.O.

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7.0 Planning for Installation

Before installing the SG-2000, some pre-planning based on the capabilities and features

of this radio should be undertaken to ensure the best possible performance.

7.1 Location of Power Supplies

If you are installing your SG-2000 in a normal environment, such as a radio room of a
ship or in a room of an office building or home, placement of the power supply is not
critical as long as it is placed within 25 feet of the radio.

If you are installing the radio in a small boat, such as a cruising sailboat or an offshore
fishing boat, you may wish to consider an additional gel cell (sealed) battery for radio
operation. In this way, should the vessel take on water during a storm, the radio will
continue to be operational.

A good way to install such a system is to place the "radio battery" in the vicinity of the
radio and place an isolator between the radio battery and the rest of the battery system.
When connected to the vessel's main batteries, the radio battery will prevent the voltage
drop which may develop on long cable runs and will assure peak radio performance.

7.2 Control Head Placement

One of the advantages of SG-2000 / PRC-2250-MIL ownership is that control heads may
be placed anywhere within 50 meters of the radio unit. This provides a high degree of
installation flexibility. Consider some of the more common civilian uses.

Marine. On a vessel, you may want to have a control head located at the bridge,
navigation station, in the cockpit of the vessel and perhaps in staterooms. If you are
planning extended cruising on a typical ocean-going sailboat, usually two heads are
planned, one at the navigation station and another in a watertight case in the cockpit.
This is because in most serious ocean cruising, the owner's stateroom is not used as
often as the navigator's quarter berth, usually located very close to the navigation
station.

Mobile. Installation in a mobile environment is something else. If you are the only
radio operator on a small four wheel drive vehicle, such as a Chevrolet Geo Tracker,
which we use as a test bed for mobile systems, you will likely have a single control head
and this would be mounted on the dashboard using the 5-way suction cup mount.

If your mobile installation is larger, as in a bus or large recreational vehicle, you may
wish to have one control head in the rear area and another control head in the vehicle

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SG-2000 MANUAL 21

cockpit.

Aviation. Installation on aircraft presents an unusual challenge. In most cases, the
control head is mounted separately from the radio. This allows the radio unit to be
placed very close to the aircraft center of gravity.

7.3 Control Head Wiring

The control head cables which are used with the SG-2000 are designed for use in normal
conditions. This means that the cables are suitable for use in mobile and fixed
installations. Very high vibration environments and mounting in military situations
require special precautions.

In high vibration environments, wire chaffing must be avoided. Although it will take
more installation time, secure all wiring tightly to prevent movement. Once movement
begins, the protective covering of wiring can be quickly worn away. This is especially
true on a tug boat, for example, where vibration caused by the ship's large propeller can
cause 1/8" to 1/2" vibration and rates of 10 cycles per second or more. A shaking
control head wire moving even a fraction of an inch as it passes through a clamp will
ultimately fail.

Military installations require a different approach. The danger here is not vibration but
shrapnel. The most common methods used are either to bury the cable in a trench one
half meter deep, or, if the ground is hard or rocky, to place one or more layers of sand
bags over the cable.

7.4 External Speakers

The SG-2000 has no separate front panel headphone jack because the radio front panel
is weather-resistant and a headphone jack is just another hole that reduces the weather
resistance of the control head.

If you plan to use high impedance headphones, such as the type included in a telephone
handset, you will connect these to the radio via the microphone jack. On the other
hand, use of a low impedance headphone requires the use of the external speaker jack,
which is present on the rear panel of the SG-2000 main unit. The J-505 jack, the external
speaker jack, is also where a low-impedance Weatherfax modem may be connected.

The speaker jack on the rear of the SG-2000 is controlled like the front panel speaker.
In other words, when the SPK (speaker) is disabled on the control head, the remote
speaker which is wired in parallel with control head #1 speaker is also turned off.

Important Note: The rear panel speaker is only available
when the control head of the SG-2000 is attached to the
radio. This is because a separate speaker audio line is run
from the attached control head (where the audio amplifier is

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SG-2000 MANUAL 22

located) to the rear panel. When the head is detached, this
wiring is no longer available.

7.5 External Accessories

External accessory location should also be part of the planning process. If you are
planning to add external equipment such as a Weatherfax receive modem, a terminal
node controller (TNC) for amateur use, a commercial standard SITOR modem, such as
the SGC TELEREX™ system, or an ALE controller such as the SGC HardLink™ System,
provision for the mounting and operation of these items should be made at the time of
installation.

When planning the use of an external audio input to the SG-2000, make provision for
switching the external audio source on and off. This is necessary because the external
audio input feeding the SG-2000 is an unswitched bridge. In order to avoid transmitting
a microphone and line input signal (via J301) at the same time, you must be able to turn
off the line input source.

If you are planning to use some external units, you may need to plan additional space
for peripherals which may be required. As an example, the ALE controller requires a
video display terminal (or IBM-PC type computer) to access programming. This may
be a single unit terminal and keyboard, or it may be discrete keyboard and display
units.

A TNC may require a printer, a computer, or both. Provision for mounting of these
items is a good idea, especially if you will be adding them in the future.

Because of the larger number of options available, the subject of external radio
peripherals is covered in more depth later in this manual.

Look ahead — and plan for your future needs before you begin your installation!

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SG-2000 MANUAL 23

8.0 Radio Licenses

Finally, before we discuss installation of the SG-2000 radio, we should discuss licensing.
The operation of an SG-2000 generally requires two types of licensing. In the United
States, both a station license and an operator permit are issued by the Federal
Communications Commission. The SG-2000 is type accepted for use on both U.S.
marine and amateur bands. Therefore it is exempt from Part 97.11 (b) regulations
requiring separation of marine and ham radio equipment. Part 97.11 (b) prevents ham
radio equipment from being used on commercial bands but does not preclude use of
type-accepted commercial equipment on the ham bands.

8.1 Station Licenses

The U.S. F.C.C. issues licenses for the operation of many classes of radio stations. This
includes ham radio stations, commercial marine shore stations, shipboard stations and
those involving various kinds of mobile applications such as HF systems aboard
aircraft. There is an exception, however. Stations operating under the auspices of the
U.S. military and stations in the Military Affiliate Radio System (MARS), are exempt
from the licensing requirements of the F.C.C. but are subject to military rules. Most
countries have comparable regulations.

Generally, the charge, if any, for filing a station application is modest. If you are
planning to operate a U.S. commercial radio station, such as one aboard a fishing boat,
simply call the F.C.C. Regional Office (there are 12 regional offices located in the U.S.)
and ask them to send you the appropriate paperwork. Outside the U.S., check with
government authorities.

The same goes for pleasure craft such as cruisers, sports fishing boats, and sailboats.
The definition of "commercial station" means that the radio can be used for conduct of
"business."

It is generally a simple process to fill out the application form for a commercial license.
You may find that you will be asked for the SG-2000 Type Acceptance number. This is
not the model number of the SG-2000. It is the F.C.C.'s unique identifier which
references the official testing and approval paperwork.

On the license application, where "Type Acceptance Identifier" is requested please fill in
the following:

CFT8DKSG2000

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