Specifications

SMARTUNER MANUAL 12

SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

E-Mail: sgc@sgcworld.com Web Site: www.sgcworld.com

longer. In addition, the SMARTUNER 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 generally 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 antenna overcomes the radiation problem.

4.2 Whip Antennas

2.5 to 3.0 Meters (8 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

longwire 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 Longwire Antenna—23 Meters (75 feet); 46 Meters (150 feet)

For most applications, the longwire 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