SGC-239 Autotuner

This is a small autotuner (coupler) with a frequency range of 1.8-30 MHz. I use it for my base station with twinlead feedline, but it's equally at home in mobile short antennas fed with coax. The justification for me making the purchase was that the impedance matching range was listed as .5 ohm to 5K ohms, plus the ability to tune with less than 5W input. I see that SGC no longer advertises the matching range. But it probably hasn't changed. For more info, SGC's web page is here
Because it is housed in a aluminum enclosure that is NOT waterproof, mine is mounted on the inside of the basement wall about 6 feet up from the floor. Ladder line feedline comes into the basement through the base plate to the coupler. A photo of one enclosed in a plastic kitchen storage bowl is at the bottom on the left. This is a handy item to use as an outdoor enclosure, photo by W4PAH.

It is interesting that it's power specification changes with wire length and frequency, see below. Here are some specs from the web page.

Frequency range vs antenna length:
9 feet (7-30 MHz @ 100W)
40 feet (3-30 MHz @ 200W)
100 feet (1.8-30 MHz @ 100W).
Power rating: 200 watts PEP maximum: 12VDC.
SWR: Less than 2:1 typical
Minimum tune power: 1.5 watts typical
Overall dimensions 7.5 x 6 x 1.85 inches
Under 2 pounds

Click here to review the manual in pdf format.

Created/Revised 27 November 2012
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