The SG-230 automatic antenna coupler is made by SGC, Inc., makers of HF radios, couplers, and antenna. The microprocessor controlled antenna coupler can be used within its' power rating with any HF transceiver that operates between 1.6 and 30 MHz. It is designed for marine, portable and fixed base applications. Recommended antenna types are 23 ft marine whip for 1.6 to 30 MHz operation and a 9 ft. minimum antenna for 3-30 MHz operation. The power rating is 200 watts PEP maximum, and the unit runs on 12VDC. The SWR after tuning is less than 1: 1.5 and requires at least 3 watts of RF to tune. It is supplied with a 9 ft. cable for coaxial and DC power. As you can see, I have the SG-230 mounted in the rear of my Cherokee, tucked into a area between the wheel well and the tailgate. The coax and control lines are routed under the body panels. You can see the porcelain insulator on top of the unit, connected to the high-voltage feed line going to the 9 foot whip antenna.
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The company provides an optional control unit, which indicates tuning
status, provides power control, etc. They also provide the wiring diagrams for this
unit so you can make your own if so desired. I made one (pictured to the left) and connected it to a long control cable. The small control box sits between the two front seats, making it very easy to use. It provides for power ON/OFF, a tuned indicator, and also locks the automatic tuning circuitry to prevent undesired interaction with highway objects (like tractor trailers, etc.) |
A lot of people have asked me how I like it. Well, it sure beats manual tuners, stopping to change antenna resonators when mobile, or having to figure out where to put that SWR meter on your dashboard. I have trouble tuning up on 20 meters, but it is not the coupler's fault. My installation is just the exact combinations of antenna length, feedline routing, etc. which makes for a unique impedance matching problem. I could shorten or length the antenna and fix the problem, but I don't really care to work 20 meters mobile so I've not bothered to fix it.
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