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.

Mailing: PO Box 3526, Bellevue, WA 98009

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

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

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© 2001 SGC, Inc.

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.

Mailing: PO Box 3526, Bellevue, WA 98009

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

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

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© 2001 SGC, Inc.

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.

Mailing: PO Box 3526, Bellevue, WA 98009

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

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

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© 2001 SGC, Inc.

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.

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]

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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.

Mailing: PO Box 3526, Bellevue, WA 98009

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

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

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© 2001 SGC, Inc.

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

Mailing: PO Box 3526, Bellevue, WA 98009

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

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

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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

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.

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

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]

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