SGC SG-231 Operating Manual

SG-231

Smartuner®

Microprocessor Controlled Automatic Antenna Coupler

Installation and Operations Manual

Getting the most from every watt of HF-SSB Power

SG-231 Smartuner TM

Slim Design with Simple Mounting

The SG-231 is a slim design that will easily fit in the most compact installations. The unit measures only 11.5D x 9.5W x 1.7H inches, and weighs 3.8 lbs. The SG-231 is waterproof and is designed to be mounted at the antenna feed point for maximum efficiency. Easily configured for tower mounting.

Antenna Applications:

• End-fed wires

• Center-fed dipoles

•

Inverted “L”s

•

Loops

•

Mobile whips

•

Vee Beam

•

Many others

SGC SMARTUNER TM Family

SG-237

SG-230

SG-235

SG-231

SG-230
		SG-237		SG-235		SG-231
1.6 - 30 MHz
3 to 200watts		1.8-60 MHz		1.6 - 30 MHz		1	- 60 MHz
		3 to 100watts		3 to 500watts		3	- 100 watts

The SGC Building, 13737 S.E. 26th Street,

P.O. Box 3526, Bellevue, WA 98009 USA

No Compromise

Phone: [phone] FAX: [phone]

Communications

E-mail: [e-mail] www.sgcworld.com

© Copyright November 2000 SGC, Inc.

SG-231

ANTENNA

COUPLER

Installation and Operations Manual

Updated: November 2000

CAUTION: Carefully read the “Quick Start” on the following page and all pertinent sections of this manual prior to operating your Smartuner for the first time. This unit will provide outstanding service if you follow the detailed recommendations within this manual.

SG-231 MANUAL

i

Quick Start Guide

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

1.An HF/VHF radio with 3 to 100 watts output.

2.An HF antenna with a wire feed (not coax fed).

Minimum length of 7 feet (to 3.5 MHz) or 23 feet (1.8 MHz).

3.A good ground (counterpoise) for the antenna and coupler.

4.+12 VDC and ground for the coupler.

5.SmartLock Pro coupler controller (optional).

Connections:

Connect the Smartuner as shown in the following diagram:

GROUND (Counterpoise)

TO TRANSMITTER (3 to 100 w)

Single Wire

RG-58 COAX

ANTENNA

Orange : Option A

Violet : Option B Brown: Not used Blue : Reset

White : Hold (Locks coupler settings) Green : Tuned Indicator

Black : DC Ground Red : +12 to 15 VDC

To SmartLock Pro optional

Operation:

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

2.As power is applied, coupler should make one “click” sound.

3.Coupler should come up in the bypass (un-tuned) state.

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

5.Tuning should be done at full power. Clicking is heard.

6.When tuned, clicking stops and Green wire goes low.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL

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	Table of Contents
Quick Start Guide.........................................................................................................		i
1.0 General Information...............................................................................................		1
1.1	Users Experience ........................................................................................	1
1.2 What Is an Antenna Coupler ....................................................................		1
1.3	Overall Description....................................................................................	2
1.4 Coupler Network Configuration .............................................................		3
1.5	Operation Indicators..................................................................................	4
1.6	Mechanical Design .....................................................................................	4
	1.6.1 Marine Mounting ........................................................................	5
	1.6.2 Desert and High Temperature Installations............................	5
	1.6.3 Direct Weather Protection Installations ...................................	5
1.7	Remote Installations...................................................................................	6
1.8 Upgrade Sequence......................................................................................		7
2.0 Specifications………………………………………………………………………7
2.1	Accessories ..................................................................................................	7
2.2 Recommended Antennas ..........................................................................		8
3.0 Parts and Technical Support.................................................................................		8
3.1	Parts Furnished...........................................................................................	8
3.2	User Supplied Items...................................................................................	8
3.3	Technical Support.......................................................................................	8
4.0 Antenna Types........................................................................................................		9
4.1	Antenna Selection.......................................................................................	9
4.2 Whip Antenna.............................................................................................		10
4.3 Long wire Antenna ....................................................................................		10
4.4 Back Stay Antenna .....................................................................................		11
4.5	Typical Installations...................................................................................	11
4.6 Apartment Loop Antenna.........................................................................		18
4.7	Recreational Vehicle (RV) Antennas .......................................................	19
	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL

iii

4.8 Aircraft Antennas…………………………………………………………20
4.9 Low Profile, Hidden and Covert Antennas		............................................ 21
4.10 Emergency Antennas...............................................................................		23
	4.10.1 Kite Antenna ..............................................................................	23
	4.10.2 Tactical Installations..................................................................	23
5.0 General Notes on Antennas and Couplers.........................................................		24
5.1	Steps to Antenna Installation....................................................................	25
5.2	Antenna Location .......................................................................................	26
5.3 Ground Systems—General .......................................................................		27
	5.3.1 Vehicle Grounds ..........................................................................	27
	5.3.2 Marine Grounds ..........................................................................	27
	5.3.3 Base Station Grounds..................................................................	29
5.4	Corrosion ....................................................................................................	29
5.5 Antenna Coupler Mounting .....................................................................		30
5.6 Antenna Connection ..................................................................................		30
6.0 Installation Procedures..........................................................................................		30
6.1	Installation with SG-2000 ..........................................................................	31
6.2 Installation on ALINCO DX-70................................................................		31
6.3	Installation on other Radios......................................................................	32
6.4	SmartLock Pro Installation .......................................................................	32
6.5 Weatherdeck Mounting.............................................................................		33
6.6	Electrical Checkout.....................................................................................	34
6.7	Alternate Electrical Checkout...................................................................	35
7.0 Coupler Configuration……………………………………………………………37
7.1 Schematic Diagrams...................................................................................		37
7.2	Tuning Process............................................................................................	37
7.3	Impedance Detector ...................................................................................	38
7.4 VSWR Detector ...........................................................................................		38
7.5	Phase Detector ............................................................................................	38
	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL

iv

7.6	Central Processing Unit (CPU).................................................................		38
7.7	Initialization ................................................................................................		39
7.8	Bypass Operation, Jumpers ......................................................................		39
8.0 Tuning Process........................................................................................................			40
8.1	Program Description..................................................................................		41
8.2	Tuning Paths ...............................................................................................		42
		8.2.1 Antenna Too Short ......................................................................	42
		8.2.2 Antenna Too Long ......................................................................	43
		8.2.3 JP1—Tuning Elements Out During Receive............................	44
		8.2.4 Jp2—Tune From Memory ..........................................................	44
9.0 Smartlock Pro Operation.......................................................................................			45
9.1	Tune, Tune Lock, and Reset......................................................................		45
9.2	Smartlock Pro Notes ..................................................................................		45
10.0 Troubleshooting ...................................................................................................			45
10.1		Ground Faults ...........................................................................................	46
10.2		Antenna Faults..........................................................................................	47
10.3		Transmitter Faults ....................................................................................	48
10.4		A Final Pointer on Troubleshooting ......................................................	49
11.0 Index.......................................................................................................................			50

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	1

1.0 General Information

The Smartuner™ reputation has grown to legend status because it is simple to use and a highly reliable piece of electronic equipment. A Smartuner will provide maximum transfer of radio energy from any HF/VHF transmitter to any loop, end or center fed HF antenna within the frequency and power limits of its specifications. The SG-231 builds upon the renowned reputation of the SG-230 by adding many advanced features, among them: a new, highly technological micro controller which has built in A/D functions, non-volatile memory; improved immunity to RF interference; improved tuning precision; and the ability to be used on 6 meters.

This document is designed to guide the SG-231 Smartuner user through installation and operation of the unit. This document will also recommend various steps that may be undertaken in the field to provide correct operation of the SG-231 should difficulty be encountered. Smartuners are extraordinarily reliable. But you should be aware that there are scores of fine points to any HF/VHF installation that are easily overlooked and may cause difficulty. Our goal in this manual is to help you quickly obtain the best possible performance from your HF radio installation. By reading this manual carefully, you can avoid most of the pitfalls that can degrade the performance of your HF system.

1.1 Users Experience

The Smartuner may be installed successfully by anyone with the help of this manual. However, if you are inexperienced in HF radio installation and operation, do not be shy about seeking advice from people with more experience than yourself. They will help you achieve good results quickly and with minimum frustration. Even the most experienced professional HF users will occasionally run into difficulty.

Regardless of the level of your experience, SGC stands ready to offer you installation suggestions and help you resolve any aspect of Smartuner operation that is not entirely satisfactory. If you have a specific question, please send us a fax at our Bellevue, Washington (USA) headquarters. The number is [phone]. If you require telephone assistance, please call us at [phone] during business hours, 8:00 A.M. to 5:00 P.M. Pacific Time.

1.2 What Is an Antenna Coupler?

Antenna “couplers” are placed at the antenna and precisely match conditions of the antenna to the feed line. Antenna “tuners,” on the other hand, are generally located at the transmitter output at the radio end of the coaxial feed line. Do not be confused by the term “coupler” or “tuner.”

• A tuner placed at the transmitter fools a transmitter into working correctly.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL	2

• A coupler installed at the antenna eliminates feed line losses by providing a proper match of the antenna to the feed line. The Smartuner is a true antenna coupler.

The several key points, which we will emphasize throughout this manual, will result in the best possible operation of your Smartuner. These include:

•The coupler must be located at the antenna.

•No coax may be connected to the coupler output.

•The coupler must have clean +12 VDC power supplied to it.

•The ground system must always be larger than the antenna.

•The antenna wire should be of the largest gauge practical.

•Capacitance at the coupler output must be minimal.

•The antenna should be of sufficient length for your lowest operating frequency.

Strictly observing these basic rules will insure good operations under the widest range of conditions.

This manual should be thoroughly studied if you plan to have the best possible signal and most reliable operation of your HF system.

Please make note of the following information for your records:

Date unit was purchased: _____________________________________________

Dealer from whom Purchased: _________________________________________

Date Installed: ______________________________________________________

Type of Antenna used: _______________________________________________

1.3 Overall Description

The SG-231 is a general-purpose coupler that can operate with any type of radio and almost any type of antenna configuration. The coupler network configuration is of a pi or L type; sensors continually monitor the state of the tuning and relay this information to the processor.

The initial (first time) tuning may take several milliseconds to a few seconds depending on the complexity of the tuning process for a specific antenna configuration. After tuning the first time for a specific frequency and antenna, this information is entered in the non-volatile computer memory that will store up to 170 tuning solutions.

When the same conditions are encountered again, re-tuning is accomplished within 20 milliseconds by recalling the information from the non-volatile memory. Special software has been designed by SGC to allow accurate and fine-tuning of the coupler. For software description, refer to the MicroTune™ section of the manual.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
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SG-231 MANUAL

3

SMARTUNER

10 feet (3 meters)

To Transmitter

(side view)

RF cable

PL-259

To SmartLock Pro

Red: 12-15 VDC

Wire antenna

Control cable

Black: DC Gnd

Grn: Tuned

Large Ground (counterpoise) system

Blue: Reset

Wht: Hold

			Brn: VHFNot used
Diagram of Smartuner Installation
			Grey: SIG A

Orange: Option A

Violet: Option B

If antenna or transmitter conditions have changed since the information was stored in memory, the coupler re-tunes and a new tuning solution is achieved. This new information is stored to memory for future reference. The Smartuner will always look for the best possible tuning solution and will improve existing tuning solutions whenever possible.

The SG-231 may be bypassed and your antenna used as a broadband receiving antenna. To do this, turn off the power to the coupler for two seconds and then turn it back on, or simply press the reset button on the SmartLock Pro. In this situation, the coupler is reset to stand-by waiting for the first RF power to be transmitted before providing a tuning solution. In the stand-by mode, the antenna bypasses tuning elements and connects the antenna directly to the receiver with no tuning elements engaged. This allows for receiving signals throughout the HF range.

The coupler will cease to operate normally if input voltage drops below 10.5 VDC. This situation may occur if a marginal battery is used or if you are transmitting at high power with an inadequate power supply or battery. Batteries must be fully charged for proper operation. Large gauge wiring to the transmitter and coupler must be used to avoid re-tuning.

If broadband operation is required during scanning operations, jumper JP-1 on the printed circuit board inside the coupler may be set to the “YES” mode. This will bypass tuning elements on receive. Jumper JP-1 is located along the edge of the printed circuit board near U2.

In some cases, it may be desirable to re-tune the coupler and bypass the memory information. If you wish to bypass the recalled tuning solutions, place jumper JP-2, also located near U2, to the “NO” position.

1.4 Coupler Network Configuration

The coupler network configuration is designed with 128 different input capacitor values, 64 output capacitor values, and 512 inductor values, thus providing about a four

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SG-231 MANUAL	4

million different pi or L configurations. The coupler requires an input of 5 to 100 watts to operate. The unit operates on +12 VDC.

1.5 Operation Indicators

Operational status of the coupler and the onboard computer’s tuning decisions is displayed by five LED's, which are located on the main printed circuit board (PCB). These indicators are only visible when the cover of the coupler is removed. These five LED's are not designed to be interpreted by other than factory and trained service personnel.

CAUTION:

Dangerous high voltages exist inside the Smartuner when it is operated with an HF transmitter. High RF voltages in excess of 10 kv may be expected in normal operation of this unit. In addition to shock hazard, these RF voltages may produce burns that are very painful if you come in contact with exposed components. Therefore, DO NOT operate without the cover secured in place unless you are a well experienced radio technician or engineer.

As a matter of good installation and engineering practice, exposed metal antenna elements should be located in such a manner as to prevent accidental contact with people (especially young children), pets, and small animals.

1.6 Mechanical Design

The SG-231 is supplied in a weatherproof case with mounting holes. RF and DC power is supplied to the unit through the separate cables. One cable is a 10 foot 50 ohm coax for RF. The other is a 10 foot 8 conductor cable with wires for ground, power, optional SmartLock controls, and optional LED indicator.

The SG-231 antenna coupler’s weatherproof case is designed to withstand the environmental conditions encountered aboard ship when mounted on the weatherdecks. The internal construction is designed to withstand the shock and vibration of marine service. Corrosion-resistant hardware and passive alloys are employed throughout. We do not recommend opening the Smartuner case unless it is necessary. For 99% of installations, the factory settings for jumpers will be correct. The coupler must be installed in an area not directly exposed to the sunshine or rain. Should you have occasion to open the case, it must be re-sealed under low humidity (below 35%) and care used to ensure the gasket that seals the unit is placed properly to maintain watertight integrity of the unit.

Although the Smartuner is built very solidly, it is good installation practice to provide additional protection from the elements. SGC makes the following recommendations:

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL	5

1.6.1 Marine Mounting

The Smartuner should be located inside the house or under the aft lazaret on a sailboat. On powerboats, the coupler may be mounted outside, but an additional protective housing is recommended. The preferred installation if vertical is with the RF screw pointing upward.

RF and DC cables are provided for on the lower edge of the weather housing, along with a 1/4-20 stainless steel ground stud. The antenna connects to the screw on the top of the weather housing.

The SG-231 may be mounted in any position including inverted without any degradation of performance.

1.6.2 Desert and High Temperature Installations

The Smartuner may be used in very hot climates on a continuous basis if some additional protection from direct sunlight is provided. The best protection for a mobile installation is provided by the QMS (Quick Mounting System) that keeps the antenna coupler outside of a vehicle. Temperatures inside a vehicle may exceed 212°F (100°C). If a QMS is not used, it is desirable to keep the coupler in the shade if possible. Please refer to the diagram in the following section.

1.6.3 Direct Weather Protection Installations

We recommend placing the Smartuner under some kind of protective housing other than having the case directly exposed to sunlight and to prevent heavy build up of ice. 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.

Figure 1.6.3.1 Direct Weather Protection

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.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	6

1.6.4 Warranty Note

It is important to have protection from the elements as common weather conditions can reach beyond the capabilities of the coupler. Although the SG-230 coupler is fully waterproof and was created to withstand normal weather conditions, warranty will be voided if left exposed directly to extreme weather such as snow, rain, and ice or prolonged sun exposure. Even in milder climates, direct and constant sunlight can exceed the safe operating temperature and can shorten the lifespan of your coupler.

1.7 Remote Installations

The SG-231 is supplied with ten feet of standard RF cable. SGC has two standard lengths of antenna extension cable available in the event you need to mount the cable farther than ten feet from the transmitter. A 25-foot extension cable is available (SGC Part Number 54-67) as is a 50-foot cable (SGC Part Number 54-68).

If you need to install the antenna coupler more than 50 feet from the transmitter site, up to two extension cables may be used for a total of 75 or 100 feet. However, SGC does not recommend installing the Smartuner more than 100 feet from the transmitter because two losses must be considered.

•The first loss in long distance installations is normal attenuation of the radio signal coming from the antenna to the radio via the coax. As you may be aware, the longer the coaxial cable run, the higher the loss will be. The amount of loss depends on frequency. At 2 MHz, the loss is approximately .5 dB, while at 30 MHz the loss in 100 feet of coaxial cable is over 2 dB. This means that a 100-watt transmitter would actually deliver about 70 watts to the antenna after running through 100 feet of coax at 30 MHz.

If you are seeking the utmost performance at 30 MHz and you cannot avoid a run of 100 feet, or longer, we recommend using a larger low loss type of coax such as RG-8 (foam dielectric) or Belden type 9943 coax. Both of these will reduce attenuation to less than 1 dB per 100 feet. However, this heavier cable is harder to work with and may be quite expensive.

•The second loss which must be considered involves the losses in the DC power and reset control line. At any distance other than the 10-foot cable that is supplied by SGC, we recommend that the DC voltage at the antenna coupler be measured, because if the coupler voltage drops below 10 volts, the coupler may not operate properly.

For this reason, if distances are great, SGC recommends that the input DC voltage at the transmitter site be adjusted to provide for +12 to +14 volts at the coupler site.

We do specifically advise against use of a different power supply than the one used to power the radio because of the danger of creating ground loops which may cause oscillation of the final amplifiers or other undesired side effects. If you decide to use a

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL	7

separate power supply mounted at the antenna coupler location, please be advised that SGC does not provide technical support in this area

1.8 Upgrade Sequence

The current version of the SG-231 coupler will have a revision letter located on the printed circuit board. To continue moving forward in coupler design, the SG-231 may be revised as needed. Later revisions of the coupler will be denoted by the subsequent letters of the alphabet.

SGC will continue making incremental improvements in the Smartuner product. When you buy your product today and a new feature is added, you can always upgrade for modest fees to the latest version of the unit. If you would like to upgrade to the latest version of the unit, contact SGC because special discounts are always provided to our valued customers.

2.0 Specifications

HF Frequency Range:	1 to 60 MHz
Power Input Range	3 to 100 watts (PEP) — 50 watts max. on CW
Input Impedance Range:	45 to 55 ohms
VSWR: (Typical)	Typically less than 1.4:1
DC Input Requirement:	+13.8 VDC
DC Operating Range:	+10.5 to 15 VDC
Input Current: Average:	.9 amps
Random set time:	Typical: less than 2 seconds
Recurrent set time:	Typical: less than 10 milliseconds
Antenna Length:	Minimum length of 7 ft. —3.5 to 60 MHz
	Minimum length of 23 ft. —1 to 60 MHz
Installation:	Any position
Operating Temperature:	-35° to +70°C
Size:	9 x 9 x 2 inches
Weight	3 pounds
Case Construction:	ABS plastic cover on an anodized aluminum base
Control Cable:	Shielded 9 conductor 24 AWG with 8 pin female
	Mic connector on one end

2.1 Accessories

SGC Part Number 54-67	25 foot Extension cable
SGC Part number 55-68	50 foot Extension cable

2.2 Recommended Antennas

		SG-105 Marine and Base station antenna. This is a 60-foot end fed long wire type antenna.
		SGC Part Number 55-10.
		SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL	8

SG-107 Delta Loop Antenna. This is a delta loop 11 meters high by 11 meters wide at the base. SGC Part Number 55-12.

SG-203 Marine 28 foot whip antenna. This antenna is used for most powerboat installations. SGC Part Number 55-24.

SG-303 High performance 9-foot whip antenna. This dual element antenna is designed for severe marine and land mobile service. SGC Part Number 55-27.

SG-307 — 3.5 to 60 MHz.

QMS A Quick Mounting System which houses SG-231 Smartuner and also provides a sturdy mounting platform for the SG-307 antenna system. Designed for fly away installations requiring no holes installation of high performance HF antenna system.

3.0 Parts and Technical Support

SGC supplies SG-231 equipment; the user supplies suitable radio and antenna.

3.1Parts Furnished

1.Antenna Coupler.

2.10 foot RF cable with connectors on each end.

3.10 foot control cable with connector to coupler on one end.

4.Instruction Manual.

3.2User Supplied Items

The user of the SG-231 will need to supply a suitable HF radio antenna. Such an antenna may be as simple as an 8-foot-long piece of wire and several ground/ counterpoise radials of 8 feet or longer. The longer the antenna, up to about 80 feet, the better all around performance will be. Longer antennas may be used, but please refer to the sections on antennas for discussion of limitations.

The user will also have to supply a good counterpoise. Such a counterpoise is a large metal surface (much larger electrically than the antenna). Generally, the bigger the counterpoise, the better your signal will be.

3.3 Technical Support

Before contacting SGC for technical support, please take a few minutes to think through your installation and ask if there is anything obvious that you have overlooked in the installation. Check to make sure your ground system is both adequate and tight and that proper voltage is supplied to the coupler.

In the event you experience difficulty with your SG-231 antenna coupler, you should contact SGC for technical advise. Before calling, we ask you to have the following information ready so that we may readily assist you.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
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SG-231 MANUAL	9

Coupler Information. Please have the serial number of your coupler, the name of the dealer from whom the unit was purchased, and the approximate date of purchase.

Antenna Information. Please be ready to describe your antenna installation. You will need to advise us whether the antenna is a wire type, a dipole, V, vertical, long wire, or whip antenna.

Ground System. You should be ready to describe your ground system in detail. If you are dealing with a marine installation, you should have a description of the vessel's bonding system. If you are using the coupler in a mobile setting, you should be able to describe bonding of the hood, trunk, and other vehicle parts that may have been done. In an aircraft, you should be able to describe the location of the coupler and the type of ground connection used.

Power supply voltage. One of the common mistakes made when installing couplers is to assume that a connection is good when it hasn't been measured. If you experience any type of erratic or intermittent operation, please measure the power supply voltage inside the coupler.

Describe Coupler behavior. If you are having a problem, determine if it is happening all the time or only part of the time. Does the problem occur only on certain frequencies? Does the problem happen only in certain modes? This type of information is extremely useful in quickly isolating your problem.

Be patient. Finding the reason for less than ideal system operation may take one telephone call or it may take several calls. Regardless of how complex the problem is, your SGC representative will be able to walk you through the process of solving your problem in a logical step-by-step manner. The Smartuner and accessories will always give top performance when carefully installed.

4.0 Antenna Types

The automatic antenna coupler is designed for use with end-fed unbalanced antennas such as whips and long wires. The radiating portion of the antenna is connected directly to the coupler through a stainless steel screw. It is extremely important that the antenna type, site location, and grounding technique be correctly chosen so that the system will radiate effectively.

Broadband resonant antennas (e.g., log periodic) that cover the full range of the system may be used with the coupler if desired. Narrow band resonant antennas, such as dipoles, Vs, and inverted Vs may only be used if the antenna VSWR (including coaxial feeder) is less than, or equal to 3:1 at the operating frequency.

Note that if a dipole or V type antenna is used, the antenna may be operated at any frequency within the range of the coupler if each side of the V or dipole is 23 feet or

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SG-231 MANUAL	10

longer. In addition, the SG-231 is just as happy feeding a conventional V antenna as an inverted V. The coupler is flexible in this regard.

4.1 Antenna Selection

The automatic antenna coupler will operate into almost any end-fed antenna with a length of 2.5 meters or more, provided an effective ground is used. The antenna efficiency will be proportional to length and in most applications will be maximum at a length of 1/4 wavelength. This means that the longest possible antenna should be selected for each installation.

Very short antennas are only recommended when there is no other alternative such as in a vehicular mobile installation. The performance of short whip antennas is usually very poor, particularly at the lower frequencies, and radiation efficiency will be only a few percent of a full sized antenna. However, a special electrically long antenna such as the SG-303 9-foot mobile antenna overcomes much of the radiation problem.

4.2 Whip Antenna

2.0 TO 3.0 Meters (7 to 9 feet)

This antenna is recommended only for vehicular mobile installations. The short length will result in poorer performance compared with the longer antennas. A special high performance 9-foot antenna, the SG-303, is manufactured by SGC specifically for this problem. (SGC Part Number 55-27.)

7.0 to 8.5 Meters (28 feet)

This antenna is recommended for marine installation on smaller vessels. It may also be used in base stations if there is no way of using a longer antenna. The SG-203 is this type of antenna. (SGC Part Number 55-23.)

10.7 Meters (35 feet)

This is the preferred antenna for marine installation when there is no room for a long wire antenna. It will also provide reasonable efficiency for base station use and is the shortest recommended base antenna. (SGC Part Number 55-24 for the SG-204 35 foot whip antenna.)

4.3 Long wire Antenna

23 Meters (75 feet); 46 Meters (150 feet)

For most applications, the long wire antenna will give the best results and is recommended when practical. The diagrams at the end of this section show some recommended methods of installation. These are only a few of the many possible methods of installation, and frequently a different configuration will be the best at a particular site. SGC’s long wire antenna, 60 feet in length, provides efficient operation on low frequencies and high frequencies alike. (SGC Part Number 55-10.)

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	11

4.4 Back Stay Antenna

8 Meters (28 feet) and Longer

Although we would love to sell everyone a high performance marine whip antenna, the back stay of a sailboat is almost impossible to improve upon in most installations.

4.5 Typical Installations

Figures 4.5.1 through 4.5.11 show some typical installations for the automatic antenna coupler.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	12

Figure 4.5.1 Jeep installation

	Jeep Installation	2.0 M whip
	for Automatic	Detail
	Antenna Coupler
		Transceiver

		Coupler
	Feed-through	GTO cable
		(as short as possible)
	insulator

Figure 4.5.2 Vehicle installation

Ground	2.0 M whip
coupler
securely	Feed through insulator
to truck
Coupler

Transceiver

Vehicle Installation

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	13

Figure 4.5.3 Motor Vessel installation

Feed through insulator

Coupler

Suitable stay cable

Ground to steel bulkhead or overhead

Motor Vessel Installation

Figure 4.5.4 Base installation

7M to 10M

Ground lead 1.5M maximum

Ground rod

Base Installation

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	14

Figure 4.5.5 Base ladder installation

up to 300 feet

up to 200 feet

Balanced Line Feeders

300-600 Ohms GND Hot

Coupler

RF cable Control cable

Base Ladder Installation

Figure 4.5.6 Base installation with ground wire radials

		Insulator
	11M	2M
Insulator	30°
GTO cable		30°
Coupler

2M

Radial wires Ground cable No. 4 AWG buried in soil

(150 cm maximum)

Base Installation with

Conduit for Ground Wire Radials control cable

and coax

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	15

Figure 4.5.7 Base dipole installation

1 m e t e r
3 meters
	E 6 6 i n s u l a t o r s
Hot	( x 8 )
G N D	7 to 25 meters

Coupler

3 meters

RF Cable	Control cable

Base Dipole Installation

Figure 4.5.8 Base Quadra Loop Horizontal

Radiation

Porcelain isolators with tie rope

Coupler

Ground bolt

terminal Antenna

50 ohm terminal coax from

transmitter

Base Quadra

Loop Horizontal

The horizontal quad loop is a groundless antenna for high angle radiation and is ideal for HF communications up to 500 miles in the frequency range of 2 to 10 MHz. This configuration provides optimum near-right angle reflection to the ionosphere for shortrange communications.

A square base can be from 8 to 15 meters long and can be configured to the shape of the structure as necessary, to provide the best arrangement. The height of the supporting

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	16

poles should be 20 to 40 feet. Supporting poles should be as tall as possible to provide the antenna with the greatest isolation from industrial noise generated by the building, such as fluorescent lights and electrical motors. Loop antennas are also less susceptible to industrial RF noise generated by the building, because they are isolated from the ground system of the building.

Loop wires are attached at one end on the high voltage active side of the coupler and on the other end at the groundside of the coupler.

Figure 4.5.9 Base Delta Loop

Radiation

Coupler

Base Delta Loop

The delta loop antennas are ideally suited to long range communications due to their low angle. This configuration is best for communications ranging from 500 to 5000 miles in the HF frequency range of 4 to 22 MHz. Noise rejection is excellent, as stated for the quad loop antenna. Because the antenna system is not connected to a ground, noise rejection is enhanced. If mounted on the rooftop of the building, it is further isolated from the building, which generates RF noise.

The supporting mast should be 8 to 14 meters tall to provide good overall HF performance.

Note that with this type of antenna, the coupler may be mounted in the middle of the horizontal portion of the loop or it may be mounted at the corner. If mounted at the corner and the lead from the coupler attached to the vertical leg, the polarization of the loop tends to be vertical and is slightly better for low angle long distance communications.

Loops in the horizontal plane may also be used. This type of antenna provides exceptionally good performance on the low frequency bands for short to intermediate range communications.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
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SG-231 MANUAL	17

Figure 4.5.10 Vessel Groundless Loop

Radiation

75 feet

Vessel

Groundless	Coupler	Porcelain
Loop		isolator

Lower mast connection to coupler RF ground

The triangular loop antenna for sailboats is designed to operate in a groundless environment and still provide high performance. This type of installation will require only one insulator point on the bottom back stay and an electrical connection on top of the mast and the stay. The grounded side of the coupler should be connected to the bottom of the mast. Although not our best recommendation, this antenna will provide a workable solution in some installations.

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com

SG-231 MANUAL	18

Figure 4.5.11 Vessel insulated back stay

Porcelain isolator

	Radiation
	75 feet
Vessel	Coupler
insulated
Backstay	Porcelain
	isolator
	Ground
	connection

The insulated backstay antenna requires two porcelains isolators. The coupler must be placed as close as possible to the base of the backstay antenna. Proper grounding of the coupler is very important. Connect the RF ground terminal of the coupler to all of the metal parts or structures of the boat (keel, engine, etc.).

4.6 Apartment Loop Antenna

Loop antennas can be used very effectively in small apartments, offices, and rooms. Radiation for a loop antenna is always efficient but highly directive. Therefore, the orientation of the loop is very important. Generally, the vertical loop antenna with horizontal radiation is much preferred for a general application throughout the 1.8 to 30 MHz band. However, loop antennas can be effective when mounted horizontally to the ground to radiate vertically and provide efficient short-range communications on higher frequencies. Generally HF connections are difficult to establish in the distance range of 50 to 250 miles. In a large room (such as 20 x 30), we would recommend the installation of a single wire loop antenna mounted on the ceiling with the coupler against the wall directly below the antenna. The wire gauge should not be less than 16 AWG with insulation.

When operating in a small room, install a small multiple wire loop (six loops) on a rectangular configuration three by four feet (as illustrated in Figure 4.6.1). This configuration allows operation from 1.8 to 60 MHz, and the SG-231 will tune and load all frequencies well below a ratio of 1.4:1 VSWR. Directivity will be high from 3 to 12 dB depending upon the frequency. If this is a problem, two loops at 90 degrees can be

	SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.	P.O. Box 3526, 98009 Fax: [phone] Tel: [phone]
	E-Mail: [e-mail] Website: www.sgcworld.com