The Kenwood AT-230 is an antenna tuner that covers the 9 amateur bands from 1.8 to 30 MHz. This tuner employs an adjustable coupler, a through line RF meter and a SWR meter. The through power of the AT-230 is 200 watts maximum. It has two different RF power scale settings for the meter which is either 20 watts or 200 watts. 

The AT-230 also incorporates an antenna switch to allow the operator to select between 4 different outputs. Two of these are for coaxial fed antennas, one is for a wire antenna(ladder line) and one setting is for an external dummy load. The operator also has the choice of using his antennas with-out going through the internal circuitry of this tuner.

The input impedance is 50 ohms and the output impedance can be between 10 to 500 ohms. Or said another way, this tuner can make your transmitter happy with loads having up to a 10:1 SWR. The Kenwood AT-230 employs a Toroidal core direction coupler for the measurement of any SWR. All antenna tuners will have some insertion loss and Kenwood claims that this tuner will only have 1/2 db loss at optimum match. The minimum power needed from a transmitter is 4 watts to get the tuner working.

The AT-230 matches up very nicely with the Kenwood TS-530S and TS-820S series or radios and measures in at  7 1/16" wide by 5 1/4" high by 11 5/16" deep and weighs in at  7 1/2 pounds.  

The photograph on the left is of the side of the Kenwood AT-230. As can be seen in the photograph on the right, this tuner does not need to be this long but it is this authors opinion that Kenwood made these tuners long like this to match up with the depth of the TS-530S and TS-820S series of radios made by Kenwood. The different external color shades of gray as well as the white lettering and knob coloring matches that series of radios as well.

The photograph on the left is a picture of one of the two air variable capacitors that are used in this tuner. There is nothing really special about this picture except that I thought it was just a neat looking photograph so I decided to include it here. The picture on the right shows some of the internal workings of this tuner.

Resource:

Kenwood instruction manual