SGC SG-239 Operating Manual

SG-239

Smartuner

Manual

TM

October 2001

Cat. #54-22

SGC — The SSB People

ance single sideband (SSB) communications equipment. Since
1971, the company has sold to the marine, military, aviation,
and industrial markets worldwide. Over these years, SGC has
earned an outstanding reputation for product reliability and for
after sales service.
The company keeps pace with equipment options, en­gineering developments, and design requirements. Its products
are the most competitive in the entire long distance communi­cation market. SG C equipment is pre sently being us ed by the
United Nations for inter-communications in developing coun­tries throughout the world.
Many competitive racing vessels, as well as fishing
boats, tugs, and commercial craft are equipped with SGC
equipment. In fact, an SGC radiotelephone pr ovided the only
communications available on a past Polar expedition by the
National Geographic Society.

SGC develops, manufactures, and sells high perform-

SGC also supplies U.S. government
agencies, several forei gn governmental a gencies,
and major petroleum companies throughout Asia
and Latin America.
All SGC equipment is designed and

manufactured in the USA. SGC has qualified peo-

ple ready to provide technical information, assis-

tance in selecting equipment, and recommenda-

tions for any installation.

SGC welcomes your

call to discu ss your S SB requi re-

ments.

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Table of Contents

Specifications ………………………………………….. 5

1.0 Supplied Items ……………………………………… 6

2.0 Mechanical Design …………………………………. 6

2.1 Marine Mounting …………………………………… 6

2.2 Desert and High Temperature Installations ………… 6

2.3 Direct Weather Protection Installations ……………. 7

3.0 Coupler Configuration……...……………………….. 7

3.1 Connections to SG-239……………………………… 7

3.2 Tuning Process …………………………………….. 8

3.3 Impedance Detector…………………………………. 8

3.4 VSWR Detector…………………………………….. 9

3.5 Phase Detector ……………………………………… 9

3.6 Central Processing Unit (CPU) …………………….. 9

3.7 Initialization…………………………………………. 10

3.8 Jumper Settings………………………………… … .. 10

4.0 Tuning Process and Options ……………………….. 11

4.1 Program Description ……………………………….. 11

4.2 Tuning Paths ……………………………………….. 13

4.2.1 Antenna Too Short ……………………………….. 13

4.2.2 Antenna Too Long ……………………………….. 14

4.2.3 JP1—Tuning Elements Out During Receive……… 14

4.2.4 JP3—Tune From Memory ……………………….. 15

5.0 B.I.T.E. Status LED Descriptions……………………15

6.0 Optional SmartLock ……………………………….. 16

6.1 Tune, Tune Lock, and Reset ……………………….. 17

6.2 SmartLock Notes …………………………………… 17

7.0 SG-239 Enhanced Features…………………………. 18

8.0 Do-It-Yourself Light Bulb Dummy Load………….. 20

9.0 Five Golden Rules of HF Installation ………………. 22

10.0 S t a n d a rd Warranty …………………………….. 24

11.0 Component Location………………………………. 25

12.0 Schematics………………..……………………….. 26

13.0 Smartuner™ Comparison Charts………………….. 34

This manual is produced as a guideline for the SG-239 antenna coupler. Perform-

ance and results may vary and SGC does not warrant any installation or any result.

This manual is subject to change without notice.

SG-239

Quick Start

Installation:

To quickly install your antenna coupler you will need the
following:

1.An HF radio with 1.5 to 200 watts output.

2.An HF antenna with a wire feed. Minimum length of 9
feet (7-30 MHz @ 100W), 40 feet (3-30 MHz @
200W) or 100 feet (1.8-30 MHz @ 100W).

3.A good ground radial longer than the antenna for the
antenna and coupler.

4.+12 VDC and ground for the coupler.

5.SmartLock coupler controller (optional).

Power supply can be same as the radio or supplied by ra­dio DC switch supply line.

Operation:

1. Turn on Radio. Apply +12 VDC power to the coupler.

2.As power is applied, coupler should make one “click”
sound and is in the bypass (un-tuned) state.

3.To tune, speak normally, whistle or use CW (CW is
recommended).

4.Tuning should be done at full power for automatic.
Clicking is heard.

5.When tuned, clicking stops, the tune LED turns on and
output tune line goes low. SG-239 can be tuned manu­ally at any transmit or receive fr equenc y, five memory
bins are assigned for receive only.

6.The coupler PI network can be manually tuned and
stored in memory by using switch S1 and pushbuttons
S2-S8.

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Specifications SG-239

HF Frequency Range: 1.8-30 MHz
Power Input Range: 1.5-200 watts (PEP)

Number of channels: unlimited
Revolving memory bins: 165 TX; 5 RX
Input Impedance Range: .2-5000 ohms
VSWR: (Typical) Typically less than 2:1
DC Input Requirement: +13.8 VDC (nominal)
DC Operating Range: +10 to 18.5 VDC
Input Current: Average: 230 milliamps
Random set time: Typical: less than 2 seconds
Recurrent set time: Typical: less than 10 milliseconds
Antenna Length: Minimum length of 9 ft. - 7 to 30 MHz
Minimum length of 40 ft.-3 to 30 MHz
Minimum length of 100 ft. - 1.8-30 MHz
Installation: Any position
Operating Temperature: -35° to +70°C
Size: 7.5”L x 6”W x 1.85”H
(19cm x 15cm x 4.5cm)
Weight: 2 pounds
Case Construction: Irradiated aluminum case
Control Cable Standard coaxial and 2 wires for DC plus 2
(not supplied) wires for optional SmartLock gauge 14-18

Antenna types: 1. Whip

2. Backstay (marine, sail)

3. Dipole centerfed

4. Dipole with feedline

5. Loop (small) 2x2 multi turn

6. Loop (large) 10 ft. and up single turn

7. Longwire

8. Ladder feed

Specifications subject to change without notice.

Or CW duty cycle 40%

1.0 Supplied Items

SG-239 Coupler
Manual
Quick-Start Card

2.0 Mechanical Design

The SG-239 is supplied in an aluminum case with mounting holes.
RF and DC power is supplied to the unit through terminals accessi­ble on the outside of the case. The internal construction is designed
to withstand the shock and vibration of marine service. Corrosion­resistant hardware and passive alloys are employed throughout. For
99% of installations, the factory setti ngs for jumpers will b e correct.
The coupler must be installed in an area not directly exposed to the
sunshine or rain. Although t he Smartuner is built very solidly, it is
good installation practice to provide additional protection from the
elements. SGC makes the following recommendations:

2.1 Marine Mounting

The Smartuner should be located inside the house or under the aft
lazaret on a sailboat installed in a waterproof case. The preferred in­stallation if vertical is with the RF terminals pointing upward. The
antenna connects to the screws on the top. The SG-239 may be

mounted in any position including inverted without any

degradation of performance. To waterproof a SG-

239, place the unit in a sealable food con-

tainer, (1.7 liter - 7 cup standard size)

2.2 Desert and High Temperature

Installations

The Smartuner may be used in very hot cli-

mates on a continuous ba sis if some additional

protection from direct sunlight is provided and if

coupler is installed in a waterproof case. Tempera-

tures inside a vehicle may exceed 212°F (100°C). It is

desirable to keep the coupler in the shade if possible.

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2.3 Direct Weather Protection Installations

To protect the unit from direct exposure to sunlight and to prevent
heavy build up of ice, we recommend installing the Smartuner first in
a waterproof case then placing the case under some kind of protective
housing. If you are mounting it on a tower in a hot or cold climate, a
plastic wastebasket (such as those made by Rubbermaid™) makes an
excellent weather cover and costs only a few dollars.

Long wire antenna

Smartuner mounted inside a plastic waste
basket to protect it from extreme heat and
heavy icing. This type of enclosure is widely
available in all countries.

3.0 Coupler Configuration

Schematic Q30102900A, pg. 26, sheet 1 of 6, is the schematic dia­gram of the two basic coupler networks L & PI. Note that the L net­work as viewed from the generator, may be configured as either “C
in” or “C out,” whichever is required by the load. In either case, the
end of the network contai ning the shunt C element will be the higher
impedance end of the network.

3.1 Connections to SG-239

Drawing G30102900A, pg. 26, sheet 1 of 6 and pg. 30, sheet 5 of 6,
are the diagrams of the antenna coupler connections. RF input and
ground is applied respectively to terminals “RF in” and GND.” The
DC input is applied with the positive to the “12V” DC terminal and
“GND DC.” The “TND” terminal can be connected to transceiver or
SmartLock. This line cannot be connected to both units simultane­ously. The Hold/Reset terminal is to be reconnected to the SmartLock
option if used.

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3.2 Tuning Process

An array of detector devices in the SG-239 monitor the antenna sys­tem impedance, reactance signal, and the VSWR load when RF
power is applied to the unit. The coupler also monitors forward
power, since the control computer requires an indication of both for­ward and reflected power in order to allow tuning to proceed. The
computer uses the forward power detector as a check to ensure that
the measurements made are applied RF and are not spurious levels
from the data conversion system. The SG-239 will proceed to tune
only when enough forward power is present to confirm this check.
After RF is applied to the detector system, it then pa sses through the
coupler tuning a rray. The coupler tuning array consists of six capaci­tors in shunt on the input arm of the network, seven inductors in the
series arm, and four more capacitors in shunt on the output arm, all
arranged in binary increments. Relays are provided in conjunction
with each lumped constant and allow removal or entry as desired. A
network having 64 values on input shunt C, 16 values of output
shunt C, and up to 128 values of series L is possible with the ma­nipulation of these 17 relays.

3.3 Impedance Detector

RF transformers T1 and T3 drive the impedance bridge that is bal­anced at 50 ohms. T3 samples the line current and thus D7 out-puts a
negative DC level proportional to line current. A tertiary winding on
transformer T1 provides a line voltage sample to D2 that pro vid es a
positive voltage proportional to line voltage. R18 and R11 act as a
summing network fo r the current and voltage s ignals, with ratios
chosen, such that at 50 ohms, the summed signals result in a bal­anced or zero voltage condition. If the line impedance goes to high,
the signal from the voltage sensor will be relatively higher than the
current sensor, which will result in a net positive output voltage from
the summing network. Similarly, a low line impedance will result in
more output from the current sensor, resulting in a net negative out­put voltage from the summing network. The summing network out­put is shifted to a 0 to 5v range, then fed to the processor's A to D
converter port, and used within the micro-controller.

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3.4 VSWR Detector

A directional coupler is made up of a current transformer T2 and a
voltage transformer T 1, in conjunction with termi nation resistors R35,
R36 and R33, R34. The coupler is inserted in the 50-ohm transmis­sion line between the input connector, ST2 RF - ST3 GND, and the
tuning network. The forward power is measured across termination
R33, R34 and reflected power is measured across termination R35,
R36. Diode D1 generates a positive DC voltage proportional to for­ward power and D3 generates a positive DC voltage proportional to
reflected power. The forward DC output is fed to a voltage divider
consisting of R19 and R1 4. These voltages are input to the RF power
detector and to an A to D converter port of the processor. The re­flected DC output passes through a voltage divider consisting of R29
and R16, and then it also goes to an A to D converter port of the proc­essor.

3.5 Phase Detector

A phase detector is formed by T3, A1, and their associated compo­nents. This detector indicates the state of any reactance associated
with the antenna coupler as noted from the generator. A line current
sample is compared in phase with a voltage sample in a double bal­anced mixer. Output polarity varies negative or positive d e pending on
the reactance of the antenna. The output of the phase detector A1 is
shifted to a 0 to 5v range, then fed to the processor’s A to D converter
port and used within the micro controller.

3.6 Central Processing Unit (CPU)

A tune-up algorithm, which is contained in the memory of the micro­processor, implements the antenna matching. It is designed around the
MC68HC711E9 CPU that features a versatile instruction set, RAM,
and EEPROM (memory which is sa ved after the coupler is turned
off). The antenna coupler relays are controlled by latches U6 and U7,
which receive serial data input directly from the CPU. During opera­tion, data is transferred into the CPU from the A to D ports and Input
Capture port (measures RF frequency). Basically, the program moni­tors the status of the input sensors and—starting from a preset condi­tion—uses a built-in algorithm to achieve a tuned condition. When the

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10

tuning algorithm is comple te, the CPU saves the settings in its
EEPROM, which is addressed by the applied RF frequency. This
non-volatile memory table is the basis of the exclusive learning fea­ture of the SG-239. After it has stored and latched the network status,
the CPU waits for RF to cease transmitting and returns to the Sto p
mode. When RF is re-transmitted , the first step in the tuning algo­rithm is to measure the freque ncy of the signal passing through the
coupler. From the frequency data, the computer then searches its
EEPROM for previously stored data. If data is found, it is tested for
validity, and the required “end of tune” conditions will be sensed by
the RF sensors. Then the data will be latched in place, and the CPU
will again wait for RF to cease transmitting and turn to the Stop
mode. This process takes about 10 milliseconds, which is the same
length of time that is required to close the network relays.

3.7 Initialization

The microcomputer is usually in the Stop mode and requires an in­terrupt signal (XIRQ) to start program implementation. The XIRQ is
obtained from the RF detector circuitry. This line, going low, will
wake the CPU from the Stop mode.

3.8 Jumper settings

The SG-239 may be bypassed for broad band (un-tuned antenna)
scanning listening in receive mode. All you need to do is press the
reset button of the SmartLock (if installed) or turn power to the cou­pler off and on. When the coupler comes back on, the tuning ele­ments remain out of the circuit until the Smartuner is activated by a
transmitted signal. If broad band operation is required during receive
for scan operation, jumper JP1 may be set to the Yes position. This
will drop the tuning elements out of the circuit on receive only.
Jumper JP1 is located adjacent to MCU (U5) along the edge of the
printed circuit board. Setting JP1 to the Yes position is recom­mended if you are using a radio for split band communications, for
scanning selective calling protocols, or for Automatic Link Estab­lishment (ALE). The default is: Tuning Out In Rcv: [NO].
Jumper JP3 bypasses the coupler's memories. This means that each
time the coupler is used on a different frequency, it will re-tune

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rather than use previously stor ed information. The default is: Tune
From Memory: [YES].

4.0 Tuning Process and Options

MicroT une™ Softwar e

Copyright 1991-2001
The SG-239 MicroTune™ Software is unique software which allows
precise tuning of the digitally controlled π and L net work to tune a
wide variety of antennas. The versatile MicroTune™ software offers
its user these special functions:

1. The coupler is activated whenever forward power is present.

2. In addition to sampling VSWR to d e ter mine if the coup ler should
re-tune, frequency comparison is employed. This causes the coupler
to tune when eve r the transmit frequency cha nges independ ent of the
VSWR reading.

3. Extensive tuning paths are used to test different antenna situations.
The initial tuning of a new fre quency (or switched antenna) may re­quire up to two seconds. Any further tuning is accomplished in a mat­ter of milliseconds if jumper JP3 (Tune From Memory) is in its de­fault position.

4. Facilities and algorithms are used which enable accurate tuning at
the low end of the frequency band—even on shorter antennas than
previously possible.

5. The BITE (Built-In-Test-Equipment) Indicator Tune LED includes
a safety feature that alerts the operator to a mismatched cond ition,
with blinking indicators, when proper tuning conditions have not been
met. In this situation, the software will “time out” within 20 second s
unless a new frequenc y is sensed, which will cause a n immediate time
out, and the coupler will attempt to matc h the new frequency. The mi­croprocessor of the coupler “wakes up” every time the coupler has
forward power. However, re-tuning takes place only if the frequency
has changed or the VSWR exceeds 2:1.

4.1 Program Description

When DC power is applied, the computer initializes the processor reg­isters in accordance with the hardware. All tuning elements are then

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removed and the 'tune' indicators are turned off. At this time the
computer reverts to a "sleep" mode awaiting RF power or pushbut­tons S2-S8 in Manual Mode.

4.1.1 Auto Mode

Detecting forward power. Once forward power is detected and the
optional SmartLock is switched to Normal, the current coupler set­tings are sent to the relays. Ne xt, the VSWR is checked and the fre­quency measured. If the VSWR is greater than 2:1 or a difference in
frequency is detected, the program branches to the re-tune program.
If it is determined that the VSW R is les s than 2:1 and the frequency
has not changed, the computer returns to the Stop mode. Re-tuning.
Once it is determined that re-tuning is necessary, a test is made to see
if JP3 is set to tune from memory. If the res ult is re-tuning from
memory, settings are recalled from the EEPROM based on the fre­quency measured. The recalled data is then tes ted for validity. If the
data proves invalid, it is bypassed and re-tuning is performed. If the
data recalled proves valid, the data is sent to the relays and the
VSWR is checked. If the VSWR is less than 2:1, the p r o gram
branches to the “OK Tuned” section of the program. If the VSWR is
found to be greater than 2:1, the program branches to the “re-tune”
program.

Selecting tuning path. Several tests ar e made to determine which tun­ing algorithm or path should be used to tune the coupler. These tests
are based on frequency, antenna input impedance, antenna phase,
and VSWR. Numerous subroutines are executed repeatedly, depend­ing on the status of the criteria mentioned above, in order to achieve
proper tuni ng.

Signaling “no-tune.” Should the initial primary tuning sequence
prove unsuccessful, secondary algorithms are attempted until all pos­sible routines have been exhausted. If, after the secondary attempts,
the coupler still cannot achieve a p r oper VSWR, the program
branches to a “no-tune” program. Here, the LED's and remote tune
indicator will blink on and off for about 15 seconds to tell the user a
proper VSWR could not be found. After the indicators stop blinking,

12

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the program waits for forward power to cease (if it has not ceased al­ready) and returns to stop mode. At this point the user should try sev­eral other frequencies. If the “no-tu ne” condition persists, check the
installation of the antenna, coupler, radio, and ground system for pos­sible problems.

Signaling “OK tune.” If the coupler achieves a good VSWR during
the tuning sequence, the program branches to the “OK Tune” section
of the code. Here, the tune indicators are engaged. A test is then made
to check if JP3 is set to tune from memory. If so, the frequency is
measured and the tuning elements used are saved in memory coupled
with a verification code. Once saved, a test is made on JP1 to check if
the duplex mode has been selected. If so, the transmit tuning elements
remain in circuit until the receive mode is verified . At this t ime, all
tuning elements are removed. The frequency is then saved for future
comparison and the CPU reverts back to the STOP mode.

4.1.2 Manual Mode

Manual Mode allows user to adjust and save settings with or without
RF power applied. See section 6 for details on use in manual mode.

4.2 Tuning Paths

As mentioned previously, various tests are executed to determine the
most logical tuning sequence to be performed. Dependent on the test
results, additional tests and ap propriate sub-routines are executed
throughout the tuning process. Following are examples of the activity
that occurs when the coupler must be matched to a frequency that re­quires a slightly longer or shorter antenna:

4.2.1 Antenna Too Short

Once coupler has verified RF power, tuning sequence proceeds as fol­lows:

1. Series inductance is added until the phase is deemed as being in­ductive. At this point it is normal for the input impedance to be lo w.

2. Input capacitance is added until the antenna is no longer inductive.

3. The program will continue to increment the series inductance
in .125 µH steps—each time normalizing the input impedance with

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input capacitance until a low VSWR is meas ured of less than 2:1.
This process will continue until the VSWR has climbed back to
higher than 2:1 or the impedance has become high.

4. The settings that gave the lowe st VSWR have been kept in mem­ory and are now recalled to verify it is a low VSWR

5. At this point the tune indicators are engaged. The current relay
data is saved if JP3 is set to tune from memory; if JP1 is set to tune
elements out during receive position, the program waits until forward
power is no longer present, then removes all tuning elements. The
frequency is saved for future frequency comparison, and the com­puter reverts to Stop mode.

4.2.2 Antenna Too Long

Once the coupler has verified RF power, the tuning sequence pro­ceeds
as follows:

1. Output capacitance is added until the phase switches to capacitive.

2. At this point, series inductance is added until the antenna is no
longer capacitive.

3. Fine tuning is performed by trying a small amount of input capaci­tance (this may o r may not be req uired).

4. At this point, the program executes the same as step 5 (antenna too
short).
The preceding gives a simplified program flow on only two possible
antenna conditions. Much mo r e complex tuning is nor mally the case.
Further detailed description, however, is beyond the sco pe of this
manual.

4.2.3 JP1—Tuning Elements Out During Receive

(Factory Default Setting: No)
YES - In this position the software will retain data required in trans-

mit to match the coupler while removing all tuning elements when
no forward power is detected.
NO - In this position the coupler will retain the required tuning da ta
and will change nothing whether in receive or transmit. If typical
operation is out of band duplex, Yes would be most likely to give
better performance. If in band operation is typical and duplex or sim-

14

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plex is the predominant mode of operation, then No is usually the bet­ter choice.

4.2.4 JP3—Tune From Memory

(Factory Default Setting: Yes)
YES - In this position the coupler will recall data previously saved

and try this data before attempting to r e-tune. If the da ta is valid and
the VSWR is less than 2:1 the tune is completed. In this position the
coupler will save any new data in its memory for any frequency. A
new frequency must fir st b e learned, while in this mode, befor e it can
be recalled.
NO - In this position, the coupler will not use previously save d tuning
data. Each time a different frequency is selected, the coupler will pro­ceed through a complete tuning sequence. Clearly, the advantage of
Yes is speed. The coupler will seem to be matched instantly when in
this position, if the frequency being used has p reviously been saved in
EEPROM. Disadvantages include a difference in frequency too small
for the computer to detect. This would resul t in r ecall of valid data
that may not necessarily present the best match. We suggest starting
with JP3 in the Yes position. If operation is as expected, don't change
it.

5.0 B.I.T.E.* Status LED Descriptions

*Built In Test Equipment

TND

This LED will light when the tuner has found an acceptable match. It
will remain lit until condition s have changed which will cause the
tuner to find a d i fferent match. (i.e. A new tr ansmit frequency has
been detected, or tuner has been reset.)

L'Z'

This LED shows the status of the antenna impedance. When lit, the
impedance is 50 ohms or less. When off, the impedance is greater
than 50 ohms.

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16

2:1

This LED will light when the VSWR is greater than 2:1. It will ex­tinguish when VSWR is less t han 2:1.

PHZ

This LED indicates the status of the antenna reactance. When lit, re­actance is inductive. When off, reactance is capacitive.

FWD

This LED indicates the presence or lack of RF power from the radio.
When transmitting, the LED will light to indicate RF is being de­tected. In receive, the LED should be extinguished.

OTHER

All LEDs will blink on and off at a rate of 2H z to indicate the tuner
was not able to find a valid match.

Note that these status LEDs are usually used to aid a technician in
diagnosing the status of the antenna system and should not be
thought of as laboratory instruments.

As the Smartuner tunes, the BITE status will be continually updated
from the CPU .

6.0 Optional SmartLock

The SmartLock allows the operator to have additional control over
the SG-239. It is not required
One can be purchased by SGC or made per the description of the
schematic in paragraph 5.2. The SmartLock provides two basic func­tions:

1. To lock the coupler in the last tu ne mode regardless of any
changes made by the operator on the transceiver or external changes
that may have occurred on the antenna. It is a very convenient func­tion especially for instable antennas (such as whip antennas on a car
in motion) or instable situations due to a system installation o r con­figuration. However, using it in this mode may be hazardous as the

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for normal operation of the coupler.

© 2001 SGC, Inc.

operator may change frequency and the coupler will not t une. It may
eventually burn coils and/or relays.

2. Reset function is convenient to force a reset in situations where a
coupler will not retune. For example, the last tune achieved on 14.1 00
with VSWR 1:1.7, the coupler is in str ucted not to retune until it
reaches 1:2.0 - If the coupler is reset and therefore will retune at your
next transmission it may tune to 1:1.1 or much better b e fo r e the last
read of 1:1.7 - reset can also be used to liste n to other frequencies out
of band of your last setting in a broad band mode, and therefore in­creasing your incoming receive level by several “S” units. Reset is
also accomplished by turning power off and on again.

6.1 Tune, Tune Lock/Reset

Tuned (gr een LED)
Turns on when the c oupler has successfully tuned.
Normal/Tune Lock
Toggle switch which allows user to prevent coupler re-tuning by
switching to the Tune Lock p osition. When in the Tune Lock p osition,
the red LED blinks to notify the u ser that the coupler is locked on the
current setting.
Reset
Pushing the red reset button al lows the coupler to be reset, if the tog­gle switch is in the normal position. This is preferred over turning the
input power off and on.

6.2 SmartLock Notes

The Tune Lock function is in most cases unneeded. Inadvertent retun­ing is a rare occurrence. Retuning may occur when the environment or
antenna system has changed. In this case, retuning is within normal
operation of the coupler.

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17

+13.6VSW

R3

RED

+13.6 VSW

GREEN

TUNED FROM COUPLER
NO T UNE /

WHIT E

RESET FROM COUPLER

BLACK

GROUND

CA1

Red

Green

Whi t e

Black

C1

0.1µF

330

C3

0.1µF

R1
150

D1
1N757

DS1
Green LED

Q1
2N2222

C2

0.1µF

3 45261

NORMA L

SW1
DPDT

DS2

Red LED

R2

330

RESET

SW2
PUSH But t on

7.0 SG-239 Enhanced Features

1. Clear (Erase) all 170 memory bins
A. Set Auto-Manual slide switch position to AUTO.
B. Remove DC power from SG-239
C. Depress both ‘Cin Up’, (S3) and ‘Cout Dn’, (S8). Keep

both depressed for next step (Step D).

D. Apply DC power to SG-239. In less than one second, all

status LED’s will start to flash on and off.

E. Once LED’s start flashing, memory will have been

erased and S3 and S8 can be released.

End of procedure

2. Clear single unit memory bin
A. Set auto-manual slide switch position to auto.
B. Transmit on frequency to recall desired memory bin.
C. Switch the transceiver to receive mode.
D. Set auto-manual slide switch position to manual.
E. Momentarily depress ‘SAV’, (S2).
F. Return auto-manual slide switch position to auto.
G. Momentarily depress ‘SAV’ (S2). Current memory bin

has been erased.

18

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www.sgcworld.com • Email: [e-mail]

© 2001 SGC, Inc.

End of procedure

3. Manual tuning in transmit
A. Set auto-manual slide switch po sitio n to manual.
B. Engage transmitter. Not more than 10-15 watts is recom-

mended to avoid accidental RF burn.

C. Use S3 thru S8 to tune the SG-239. Each time a switch is

depressed, the status LED’s are updated.

D. You may save the settings for this frequency by momen-

tarily depressing ‘SAV’, (S2) while transmittin g.

End of procedure

4. Manual tuning in receive - “Silent Tuning”
A. Set auto-manual slide switch po sitio n to manual.
B. Engage receiver.
C. Use S3 thru S8 to adjust for best receive signal. Note:

Status LED’s are not updated in receive.

D. See appropriate procedures for saving and recalling re-

ceive only memories (below in paragraphs 5 & 6).

End of procedure

5. Saving a receive only setting into memory
A. Set auto-manual slide switch po sition to manual
B. Momentarily depress ‘SAV’, (S2) the current RX memory

channel will be displayed with the stat us LED’s. (Far left
LED is channel 1). If no LED is lit, current channel is zero.

C. Select desired channel with S3 (Chan Up) and S8 (Chan

Dn). Current channel selected is updated as switches are de­pressed.

D. Momentarily depress ‘SAV’ (S2) and current settings will

be saved to displayed RX memory bin. Note: Saving to chan­nel zero aborts save.

End of procedure

6. Recall receive only channel from memory
A. Set auto-manual slide switch position to auto.
B. Momentarily depress ‘SAV’, (S2) the current RX memory

channel will be displayed with the stat us LED’s. (Far left
LED is channel 1). If no LED is lit, current channel is zero.
(recall channel zero aborts recall)

C. Select desired channel with S3 (Chan Up) and S8 (Chan

Dn). Current channel selected is updated as switches are de-

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19

pressed.

D. Momentarily depress ‘SAV’ (S2) and saved settings will

be recalled from displayed RX memory bin.

End of procedure

Additional Notes:
Note 1: Saving and recalling receive only memories
The two procedures are basically the same with the ex-

ception of the auto-manua l slide switch.
SET TO MANUAL SAVE
SET TO AUTO RECALL
Note 2: Fine tuning a transmit freq uency
Auto tune the frequency as normal.
Switch auto-manual to manual
Fine tune settings with S3-S8
While transmitting, depress ‘SAV’ (S2) to update trans-

mit memory bin.

8.0 Do-It-Yourself Light-Bulb Dummy Load

Any time that a transmitter is used, it must b e outputting into a load.
A load is anything that the output power can be pumped into. If the
transmitter is operated without any sort of load connected, the final
amplifier stage could become severely damaged. The problem is that
you should never test a transmitter on the air for the first time, if you
are unsure about how to opera te it, and if you are unsure whether it is
working properly. You could create harmful interference to other
stations.

To test transmitters without ac tually operating into an ante nna,
dummy loads were created. A dummy load is a load that will dissi­pate the energy from the transmitter instead o f emanating it into the
ionosphere. Nearly all commercial dummy loads are large oil-filled
cans. These dummy loads change t he tran smitted energy into heat,
which is absorbed by the oil. Because different transmitters output
different amounts of power, different sizes of dummy loads must be
used. Dummy loads for typical amateur powers (<500 watts) are
relatively inexpensive and are readily available.

20

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

© 2001 SGC, Inc.

Unfortunately, when you use a can-type dummy load, you can't see
"what's happening" with your transmitter. I n this case, you can use a
light-bulb dummy load to test your transmitter. Here, the light bulb is
directly connected to the output of the transmitter and it dissipates the
RF energy as light. The light bulb d ummy load is more useful than the
oil-can type because you can guess how much power is being output,
you can see the voice modulate the SSB (the light will flicker with
your voice peaks), and you can tune the transmitter for maximum out­put (if the transmitter is an older model that requires tuning).

Before building or using the light-bulb dummy load, remember that
these models typically don't dissipate the transmitter's output as well
as an oil-can dummy load. The result is t hat RF will "leak" out; we
have heard a few stories of amateurs who were heard around town
while operating their transmitters into a light-bulb dumm y lo ad. If you
use this system, make sure that you test the equipment on a clear,
harmless frequency (NEVER test with the transmitter set on an emer­gency frequency, such as 2182 KHz).

SGC recommends that you build the light-bulb dummy load with the
following parts (although we have made one with an old light fixture
and a makeshift ver­sion with just alliga­tor clip leads and a
light bulb):
* AC socket to cable
with a PL-259 con­nector (for trans­ceiver)
* AC socket to cable
with alligator clips
(needed with coupler)

RF GND

RF IN-OUT

* Light bulb to AC
adapter

Radio

* 75 to 125 watt
light bulb, 120 to
220 VAC

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www.sgcworld.com • Email: [e-mail]

RF GND

RF IN-OUT

Radio

Antenna Coupler

Antenna Jack

GND

21

* 100 watt radio transceiver
* Any SGC Smartuner or equivalent

RADIO TEST PROCEDURE

1. Connect the transceiver light bulb load to the radio RF in/out jack.

2. Turn on the radio and set the CW mode.

3. Key the PTT switch on the microphone and look at the light bulb. If
the light bulb load is connecte d and the radio is transmitting, the light
should turn on.

4. Set the radio to SSB mode.

5. Key the PTT switch on the microphone and talk into the micro­phone. Notice that the light turns on when you talk.

COUPLER TEST PROCEDURE

1. Connect the coupler to the radio.

2. Connect coupler light b ulb load to Smartuner coupler antenna out­put.

3. Turn on the radio and the Smartuner coupler.

4. Set the radio to the CW mode.

5. Key the PTT switch on the microphone and look at the light bulb.
The light should turn on if the coupler has completed its' tuning cycle
and if the radio is transmitting.

6. For further testing, follow steps 4 & 5 of the radio test procedure.
Note: The light bul b might not turn on immediately if the coupler ha s
not yet been tuned for the frequency of the transmitter. The output
power (light-b ulb brightness) is greatest when the coupler is properly
tuned.
This test will ensure that the rad io and coupler are working properly.

9.0 Five Golden Rules of HF Installation

These rules apply to all types of stations, inc luding base, mobile, air­borne and marine. They are very important for planning and installing
your HF system, if you want to achieve good communications.

1. Install transceiver as close to operation site and power supply sys­tem as possible (whether it is an external power supply or battery sys­tem).

2. The antenna must be installed in an open space and as far as possi-

22

Mailing: PO Box 3526, Bellevue, WA 98009

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© 2001 SGC, Inc.

ble from your operating point. Example, on a sailboat, use the backstay
as the antenna, since it is the farthest point away from the rest of the
vessel.

3. The antenna coupler must be installed at the base of the antenna.

4. Always create your own ground with radial wire or copper straps.
They are the only ones that will guarantee a solid and proper ground
system.

5. All cables - power supply, control or coaxial - must always be as
short as possible and/or necessary. Any excess cable should be short­ened to the proper length - ne ver coiled.
Following these rules will minimize marginal installations and problem
sources such as RF feedback in the radio, power supply or cables and
"hot" or RF burning microphones. If all 5 above points are followed
during the design and installation of your HF system, the operator can
expect top performance. Further information regarding applications,
installation and operation can be downloaded from our website www.
sgcworld.com. These publications include:

•

HF User's Guide

•

Go Mobile at 500 Watts

•

Stealth Antennas

•

Smartuner Antenna Co uple r Manua ls

This manual is produced as a guideline for the SG-239 antenna coupler. Performance

and results may vary and SGC does not warrant any installation or any result. This

manual is subject to change without notice.

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

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www.sgcworld.com • Email: [e-mail]

23

SG-239

SGC LIMITED PRODUCT WARRANTY

(1 Year Parts and Labor)

And SOFTWARE LICENSE

You have purchased an SGC equipment product t ogether with a license t o use
the software installed in that product. Please return the warranty registration card
that accompanies this product, so that we can assure that you receive proper war­ranty service and important notic es that may affect th e product. This SGC prod­uct is warranted to be free fr om defects in workmanship an d material for a pe­riod of 1 year from the original buyer’s date of purchase. In the event of a defect,
malfunction or failure of w hich SGC receives notice durin g the 1 year period,
SGC, at its’ option, will r epair or r eplac e th e pr oduct fr ee of char ge t o th e bu yer.
The buyer must contact SGC for a Return Material Authorization Number
(RMA) and deliver the product back t o SGC with this R MA nu mber and writte n
proof as to date of purchase. SGC will ship a new or repaired pr oduct to the
buyer, reserving discretionar y right to return a newer model that offers at l east
equal performance. The foregoing warranty extends to the original buyer and
does not include (a) buyer’s c ost to return th e product to S GC, (b) bu yer’s costs
to remove or reinstall the pr oduct for warranty work, or (c) added costs of sp e­cial expedited shipment that may be requ ested by buyer. Except for the limited
warranty stated above, and to the full extent permitt ed by law, SGC disclaims
any other express or implied warranti es and liability for any incidental, conse­quential, special or exemplar y damages in connection with its product, even i f
SGC or its agents are ad vised that such damages are f oreseeable. (Note: Some
states do not allow the exclusion or limitation of incidental or consequential
damages, so the above excl usion may not apply to you). T here is no warranty
with respect to (a) th e product’s transmissi on range or geographical coverage
which can vary by location (b) non-performance caused by using an inadequate
or improper antenna or grounding system or (c) routine maintenance, periodi c
adjustment and performance testing of the pr oduct or system. SGC customarily
charges a flat fee for r epairs performed outsid e of the warranty coverage. To
inquire about such charges, please contact SGC.

END USER SOFTWARE LICENSE

SGC warrants that the SOFTWARE included in this product will perform in
substantial accordance with the docu mentation. SGC grants to the original end
user of its product a n on-exclusive worldwid e license to operate the s oftware
installed therein. This license sha ll be transferred to any person or entity that
subsequently acquires lawful ownership of the product. This license shall be
limited to using the softwa re for c ontemplat ed operati on of SG C’s p roduct. T his
license does not permit any end user to (a) modif y or adapt SGC’ s s oftwar e or to
merge it into another progra m (b) reverse engineer, disassemble, or otherwis e
attempt to discover SGC’s software source code or (c) sub license or otherwise
transfer SGC’s software for any use oth er than operating the product originall y
purchased from SGC.

24

Mailing: PO Box 3526, Bellevue, WA 98009

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Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

© 2001 SGC, Inc.

11.0 Component Location

Mailing: PO Box 3526, Bellevue, WA 98009

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www.sgcworld.com • Email: [e-mail]

25

12.0 Schematics

VCC

.1u

C15

1

U3A

1

U2B

.1u

C16

R21

5.6k

.1

C10

GND

RF

ST3

ST2

R60

4

74HC393

0

74F74

U2A

10K

QA 3QB 4QC 5QD
VCC

A

1

Q 9Q
P

R

D

12

14

74F74

R3

1.5k

D9

0

13

6

GND

7

2

CLK

11

Q 5Q
P

R4C

D

2

U11A

C14

FREQ

QA11QB10QC 9QD
VCC

GND

A

0

CLR

8

C

L

CLK

3
2

1

R1

100

8

12

7

6

.01

CLR

1

3

L

74HCT14A

R20

D8

U3B

1.5k

74HC393

1

C9

RF-DET1

VCC

R30

IMPDNCE

VCC

10k

R22

R23 10k

R5

100k

RFP

Q1

2N2222

R17 10k

C2

R10

10k

R19

1k

C13 .01u

D1

.1

R34

R33

100

100k

R6

FWD

.001uC4.001u

3.3K

R14

390

100

1W

1W

1

U1A

4

3

2

R4

R12

R18

D2

T1

PHASE

R9

100k

LM324

1

1

7

U1B

0

5

6

100k

R13

10k

10k

R29 3.3K

10k

R11

27k

D3

C7

.001u

ABC

LM324

REV

T2

|PINETWK.SCH

|INPOWR.SCH

|MANUAL.SCH

|LINK

|CTRL.SCH

|RELDRV.SCH

SG-239 COUPLER

425-746-6310

BELLEVUE, WA 98005

13737 SE 26TH STREET

SGC, INC.

0

R8 100k

R7

100k

8

U1C

LM324

0

0

10

9

C3

.001u

10k

R16

1.5K

C12

.01u

D7

C6

1W

100

R36

1W

R35

100

D4

R15

3

4

1

100

A1

R26

2

5

6

R28331W

33

1W

R27

.001u

T3

RF PATH

A Q30102900A A

Date: May 1, 2001 Sheet 1 of 6

Size Document Number REV

Title

R24

4.7k

1k

R25

C5

.001u

C11

.01u

8

R31

10

7

D6

D5

C8

15p

26

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

© 2001 SGC, Inc.

DATA

STROBE

CLOCK

R65

VCC

+

C20

4.7u

1K

C24

.1u

R58

10k

R56

10K

R52

4.7K

R51

4.7K

R55

4.7K

R98

10K

10K

HOLD

FREQ

TND

R97

D11

10K

R96

Q4

2222

HOLD

D10

R100

R99

R46

10k

10k

R45

R57

10K

R32

1.5K

20

10K

U5

2

1

PD1/TXD

2

2

PD2/MIS

2

3

PD3/MOS

2

4

PD4/SCK

2

5

PD5/S

2

6

VDD

2

7

PA7

2

8

PA6

2

9

PA5

3

0

PA4

3

1

PA3

3

2

PA2

3

3

PA1

R59

10K

Q2

2222

PD0/RXD

PA034PB735PB636PB537PB438PB339PB240PB141PB0

10K

MAN

RF PWR

RESET/HOLD

9.1V

D13

18

19

IRQ

XIRQ

O
I

S

Tuned

C23

.1u

17

RESET

Impedance

VSWR

PC716PC615PC514PC413PC312PC211PC1

68HC11

Phase

FWD Power

C22

42

C-K6

FWD1

.1u

10

MODA/LI

MODB/VSTB

43

FWD

8

9

PC0

EXTAL

R/W

VSS

VREFH
VREFL

PE7
PE3
PE6
PE2

PE546PE145PE444PE0

C25

.01u

REV1

L-U

L-D

MDE

CI-U

CI-D

CO-U

CO-D

No

Yes

Tune From

C-JP3C-JP1

JP3

1

No

JP1

1

R54

XTAL

7

6
5

E

4

A

S

3

R

2

Y

1

5

2

5

1

5

0

4

9

4

8

4

7

C26

.01u

PHZ1

REV

PHASE

Memory

Yes

Tune Out

In Receive

Y1

10M

C27

MHz

4.9152

10k

R38

10k

R41

1u

C17

35V

+

.01u

C-JP1

C28

.01u

'Z'1

IMPDNCE

BELLEVUE, WA 98005

13737 SE 26TH STREET

SGC, INC.

C19

C18

R50

R53

R40

R49

SAV

C-JP3

425-746-6310

Title

18p

18p

4.7k

1k

10k

10k

VCC

SG-239 COUPLER

A Q30102900A A

Size Document Number REV

Date: May 1, 2001 Sheet 2 of 6

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

27

U6[11..18]

U6[11..18]

U7[12..18]

U7[11..18]

U61
U61
U61
U61
U61
U61
U61
U61

K6

.1

C81

10

R82

Q5

2222

SG-239 COUPLER

425-746-6310

BELLEVUE, WA 98005

13737 SE 26TH STREET

.1

12V

.01

.01

C47

C52

C48 .01

C49 .01

U6

UCN5841A

1

0

K

1

1
2
3
4
5
6
7
8

.01

.01

C37

1

Q

1

2

Q

1

3

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1

4

Q

1

5

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1

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Q

1

7

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1

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C44

C46 .01

C45 .01

.01

C39

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C41

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C40

9

VEE

8

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STR

7

6

SDO

6

5

VDD

5

4

VSS

4

3

SDI

3

2

CLK

2

1

1

VEE

7

8

9

OE

VEE

U7

12V

C42

.01

U712

C1

R2

10K

C-K6

VCC

C29

.1u

.1

C30

2

1

CLK

SDI 3VSS 4VDD 5SDO 6STR

VEE

Q1

UCN5841A

C43

18Q2 17Q3 16Q4 15Q5 14Q6 13Q7 12Q8 11K 10

.01

C33

.01

.01

C32

U713

U714

U715

U716

U717

U718

U719

SGC, INC.

A Q30102900A A

Date: May 1, 2001 Sheet 3 of 6

Size Document Number REV

Title

DATA

CLOCK

STROBE

.01

C34

28

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

© 2001 SGC, Inc.

L8 8. 0

L6 4 . 0

L5 2 . 0

1. 0

L4

.5

L3

.25

L2

0.125u

L1

ST1

K2

K1

K14

K13

K11

ANTENNA

K3

K12

12V

SG-239 COUPLER

425-746-6310

BELLEVUE, WA 98005

13737 SE 26TH STREET

K6

16

10

C88

K20

C63

100p

SGC, INC.

R7110R72

.1

C64

51p

A Q30102900A A

Date: May 1, 2001 Sheet 4 of 6

Size Document Number REV

Title

U6[11..18]

U7[11..18]

U6[11..18]

17

C90

.1

K21

RF PATH

U7[12..18]

18

10

C91

.1

C70

.1u

10

R79

C69

.1u

50p

C21

15 14

10

R78

C68

.1u

C67

.1u

C66

.1u

C65

.1u

C72

.1u

K9

10

R77

10

R76

18 17 16

10

R75

10

R74

10

R73

C73

100p

200p

C74

C75

12 KV

K8

K7

C83

C84

.1

R64

10

R63

10

13

12

12

11

C54

1000p

13

R67

10

C86

K17

K16

C56

620p

C57

470p

390p

6 KV

12 KV

K6

D12

4004

.1

C82

.1

R62

10

11

14

15

R68

10

R69

10

R70

C87

.1

.1

K18

C58

C59

200p

330p

.1

C89

K19

C60

C61

200p

100p

C62

100p

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

29

C96

VCC

VCC ON IC 74HCT14A

5VG1

VCC

3

VO

GND

VI

U4

LM7805

1

4

.1u

14

74HCT14A

3

U11B

C100

.1u

2

C99

.1u

6

74HCT14A

5

U11C

VCC

2.2K

R84

2.2K

R85

R86

2.2K

2.2K

R87

R88

2.2K

12

74HCT14A

7

13

U11F

Impedance

VSWR

Tuned

Phase

FWD Power

DS6

DS7

DS8

DS9

DS10

T

<Z>

2:1

FWD

425-746-6310

BELLEVUE, WA 98005

13737 SE 26TH STREET

SGC, INC.

SG-239 COUPLER

Title

A Q30102900A A

Date: May 1, 2001 Sheet 5 of 6

Size Document Number REV

30

C108

12V

C107

F1

2A

D14

C106

ST-12V

GND2

1000u

RF PWR

GND1

1u

8

74HCT14A

9

U11D

RESET/HOLD

TND

.01u

.1u

C101

ST-HLD

ST-GND

ST-TND

74HCT14A

11 10

U11E

RFP

-5V
C109

10u

5

CAP+ 2CAP- 4VOUT

OSC

LV

7V+ 8

3

VCC

20V

GND

7660

.1u

C102

C110

20V

10u

U9

6

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

NOT USED GATE

C95

VCC

14

.1u

4

11

0

0

-5V

12

13

U1D

LM324

ST4

1W

R83

220K

C111

.033u

630V

C112

.033u

630V

© 2001 SGC, Inc.

SAVE/RECALLS8C-OUT DN

(CHAN DN)

C-0UT UP

IND DNS5IND UP

C-IN DN

C-IN UP

(CHAN UP)

S2

D15

10K

R39

D21

R47

10K

D20

R42

10K

D19

R43

10K

R44

10K

D17 D18

10K

R95

D16

R94

10K

VCC

SAV

MAN

S7

S6

CO-D

CO-U

L-D

S4

S3

SG-239 COUPLER

425-746-6310

BELLEVUE, WA 98005

13737 SE 26TH STREET

SGC, INC.

C35

.1

.1

C53

VCC

.1

C51

R61

2.2K

.1

C50

C38

.1

C36

.1

C31

.1

L-U

CI-D

CI-U

VCC

DS1AUTO

R37

10K

A Q30102900A A

Date: May 1, 2001 Sheet 6 of 6

Size Document Number REV

Title

R66

2.2K

DS2

MANUAL

S1

MDE

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

31

SG-239 HF Smartuner™

SPECIFICATIONS:
Power (max): 200 Watts PEP or CW*
Power (typ): 1.5 Watt PEP or CW*
Range ≥9ft. Ant. 7-30MHz @ 100W
Range ≥40ft. Ant. 3-30MHz @ 200W
Range ≥100ft. Ant. 1.8-30MHz @ 100W
Input Voltage: 12.6 VDC (nominal)
Voltage Range 10 - 18.5 VDC
Impedance Range .2 - 5000 ohms
Low Current Drain Typical 230 mA

Catalog Number 54-22

ANTENNAS:

1. Whip

2. Backstay (marine, sail)

3. Dipole centerfed

4. Dipole with feedline

5. Loop (small) 2x2 ft. multi turn

6. Loop (large) 10 ft. and up single turn

7. Longwire

1. The SG-239 universal coupler is designed for use with ANY HF transceiver or ANY antenna as specified. All installa­tion configurations are possible such as base stations, mobile, marine, aviation, and small vehicles including motorcycles
and ATV'S.

2. Only 12 Volt DC and RF connections are required for basic operation. Additional connections are supplied for user
specific applications.

3. WARNING! High voltage is present on antenna terminal. Avoid contact or RF burns may occur.

4. For end fed antennas, use a ground system of several radials which are electrically longer than the radiating portion
of the antenna. Radials assure a stable, reliable and electrically 'quiet' ground system, free from electrical noise and RF
pollution. Do not use hand rails, metal roofing or ground stakes for a ground system as they are generally contaminated
and unstable.

5. The SG-239 can be used next to your transceiver as a RF line feed trimmer for balanced or unbalanced lines of 100­1000 ohms or coaxial lines (25-100 ohms). The unit does not require a balanced transformer to perform efficiently.

6. For best system and operation efficiency, we recommend installing your antenna in the open and far away from your
operating point. Put the Smartuner as close as possible to the base of your antenna system.

* For 40% Duty Cycle

IMPORTANT NOTES:

S1

MODE

PI Network Manual Tuning

S2 S3 S4 S5 S6 S7 S8

SAV

HLD/

TND

RSET

OPTIONAL

C out L C in

12V GND

DC

GND

RF

RF IN

Notes:

Mailing: PO Box 3526, Bellevue, WA 98009

Shipping: 13737 SE 26th St., Bellevue, WA 98005

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

33

34

Application Chart

Model SG-239 SG-237

PCB

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

Introduction Year 2001 1999 1999 1999 1987 1995 1992

SGC Catalog Number

Shipping: 13737 SE 26th St., Bellevue, WA 98005

www.sgcworld.com • Email: [e-mail]

Mailing: PO Box 3526, Bellevue, WA 98009

Marine

Commercial

Radio Amateur

Aviation

Special Applications

Portable

Power Input Range

54-22 54-19 54-18 54-20 54-12 54-17 54-15

x x x x

x x x x x
x x x x x x
x x x x
x x x x
x x x x

1.5-200 3-100 3-100 3-100 3-200 3-100 3-500

SG-237 SG-237

Porta

SG-230 SG-231 SG-235

(PEP Watts)

HF Frequency Range

© 2001 SGC, Inc.

Total combinations of
elements

Suggested Retail

1.8-30
MHz

1/8 million 1/2 million 1/2 million 1/2 million 1/2 million Four

$249.95 $249.95 $359.95 $595.00 $595.00 $595.00 $1595.00

1.8-60
MHz

1.8-60
MHz

1.8-60
MHz

1.6-30
MHz

1-60

MHz

million

1.8-30
MHz

1/2 million

Description SG-239 SG-237 SG-230 SG-231

HF Frequency Range 1.8 - 30MHz 1.8 - 60MHz 1.6 - 30MHz 1 - 60MHz 1.8 - 30MHz
Power Input Range (PEP 1.5 - 200 3-100 3-200 3-100 3-500

Cont. CW Power (watts) 80 40 80 60 200

Input Impedance Range 45-55 45-55 45-55 45-55 45-55

VSWR (Typical) <2:1 <2:1 <2:1 <1.4:1 <2:1

DC Input Requirement 13.8 13.6 13.6 13.6 13.6

DC Op. Range (VDC) 10 to 18.5 10 to 18 10 to 18 10 to 18 10 to 18

Input Current (avg. amps) 0.23 0.3 0.9 0.5 1.4

Random Set Tim es ( s ec) <2 <4 <2 <4 <2

Recurrent S et Ti mes (ms) <10 <10 <10 <10 <10

Non-Volatile Memory 170 170 170 170 170

Total combinations using 1/8 million half million half million f our million half million

Antenna Leng th op erating 40 feet min. 8 feet min. 8 feet min. 8 feet min. 23 feet min.

Antenna Leng th op erating
from th e l ow e s t freque ncy

Elements confi g u ration Pi & L Pi & L Pi & L Pi & L Pi & L

Input Capaci tance min. 50pf 50pf 100pf 50pf 100pf

Input Capacitance max. 3150pf 6400pf 6400pf 6400pf 6400pf

Inductance minimum 0.125µH 0.125µH 0. 25µH 0.125µH 0.125µH

Inductance maximum 15.875µH 32µH 64µH 64µH 32µH

Output Capacitance min 50pf 12.5pf 25pf 12.5pf 12.5pf

Output Capacitance max 740pf 200pf 800pf 400pf 400pf

Installation Any position Any position Any position Any position Any position

Operating Temperature -35C to +70C -35C to +70C -35C to +70C -35C to +70C -35C to +70C

Environmental None Waterproof at immer- Waterproof at immer- Waterproof at immersion of Waterproof at immersion of

Size Overall 7.5”Dx6”Wx1.85” H

Weight 2 lbs. (0.75kg) <2 lbs. (<0.75kg) 8 lbs. (3.5kg) 3.8 lbs. (1.6kg) 8 lbs. (3.5kg)

Case Construction Aluminum case Plastic ABS

Cable(s) (NOTE: All
couplers require RF and
12 volt lines onl y. S G C
cables are req uired for
additional features only.)

100 feet min. 28 feet min. 23 feet min. 23 feet min. 150 feet min.

(19cmx15cmx5cm)

Terminals SGC cable, 9 feet

6”Dx7”Wx1.5”H

(23cmx18cmx4cm)

Waterproof case

coaxial and two po wer
wire input, and RMT
tune and SmartLock

Mailing: PO Box 3526, Bellevue, WA 98009

wire.

Shipping: 13737 SE 26th St., Bellevue, WA 98005

16”Dx12”Wx3”H

(41cmx31cmx8cm)

Plastic ABS

Waterproof case

SGC cable, 9 ft coax ial
and two power wire
input, and RMT tune
and SmartLock wire

11.5”Dx9.5”Wx1.7”H
(29cmx24cmx4cm)

Plastic ABS

Waterproof case

10 feet RG-58 power cable,
10 feet RG-58 coax cable
with PL259 connectors

SG-235

16”Dx12”Wx3”H

(41cmx31cmx8cm)

Plastic ABS

Waterproof case

SGC cable, 9 ft coax ial and
two power wire input, and
RMT tune and SmartLock
wire.

Toll-Free: 800-259-7331 • Phone [phone] • Fax: [phone]

www.sgcworld.com • Email: [e-mail]

35

Base Delta Loop

Porcelain
isolators
with tie rope

Ground
bolt
terminal

50 ohm
coax from
transmitter

Base Quadra
Loop Horizontal

Ground

Aviation
control

Radio

head

© 2001 SGC, Inc.

SG-239

SMARTUNER™

Antenna Coupler

Cat. #54-22

Selected Antenna Configurations

1 meter

Coupler

Coupler

Antenna
terminal

Fixed Wing Aircraft

Wire antenna

Coupler

3 meters

E66 insulators
(x8)

Hot

7 to 25 meters

GND

Radiation

Coupler

3 meters

Coupler

At least three ground radials
longer than the flag pole

Ground
coupler
securely
to truck

Coupler

Transceiver

Coupler

2.0 M whip

Feed through insulator

Vehicle Installation

Feed through insulator

Coupler

Suitable stay cable

Ground to
steel bulkhead
or overhead

Motor Vessel Installation

Radiation

Wire goes to
the coupler

Isolator

Wire antenna

Isolator

RF Cable

Base Dipole Installation

Vessel
Groundless
Loop

Lower mast connection

to coupler RF ground

Isolator
Wire antenna

Strut to space out
antenna with plastic
tubing or fiberglass
rod

Control cable

Coupler

Rotary Aircraft

Radiation

75 feet

Porcelain
isolator

This manual is available for download at

www.sgcworld.com

up to 300 feet

Balanced Line Feeders
300-600 Ohms

GND

Hot

Coupler

Control cable

RF cable

Base Ladder Installation

Recreational Vehicle

18" PVC

Antenna Installation

pipe
standoffs

Coupler

mounted

inside coach

Use a separate ground strap or wire for the body
and the chassis to the ground of the coupler.

Coupler

Coupler

E

up to 200 feet

F

Coupler

Antenna wire

Metal roof
of vehicle

G