Electronic Design and Family Site
A Portable Tuner with internal LED SWR Meter

I needed a small antenna tuner for use with my portable emergency radio station. You never know what antenna supports will be available, and what conditions might arise; it's better to have the ability to tune anything. After much research and empirical experimentation, I decided that the basic "TEE" match was best for my needs. It is quite versatile and can match almost anything.

The variable capacitors are polyvaricons that I salvaged from old transistor AM radios. The coil was 45 turns on a 1" dia. 1" plastic pipe. I tapped the coil in 12 places to attach to a small rotary switch.

My version contains a "N7VE"-style SWR bridge as well so I don't need a separate SWR bridge to tell me when I'm properly tuned. Another advantage to this type of SWR bridge is that it presents a nearly 50 ohm impedance to the transmitter regardless of the impedance of the attached antenna; protecting the transmitter from excessive SWR while tuning. Once the antenna is properly adjusted, the bridge is bypassed.

To help its "Rugged-ness", I painted the chassis with "Plasti-Dip" rubberized coating rather than paint.  First, aluminum is notoriously tough to paint.  The quick oxidation layer it forms prevents most paints from adhering.  Then, having a literal rubber cover takes some small amount of shock out of dropping the tuner; hopefully making ti a bit more rugged.

The Schematic
R1, R2, R3, and C3 are mounted on the underside of the PCB. The remainder of the parts mount on top as normal. The dots denoted as "Gnd Connex" should be soldered on both the top and bottom of the board to tie the grounds of both sides together. The holes on either lower corner of the top side are to ground the incoming and outgoing RF connections.
The Chassis
Download a Dimensioned Chassis Drawing HERE...
Faceplate Artwork