This QRP tuner provides wide range matching of loads from 12.5-400 Ohms (& beyond) over a frequency range of 1.8-55MHz at powers of up to at least 50W. The unique design incorporates all components onto a single PCB with no air wired cores or coils. It uses a series of fixed RF inductors with self resonant frequencies well past the operating range and real air-variable capacitors instead of cheap, lossy polyvaricon capacitors. This tuner has been designed for hobbyists interested in integrating a tuner into their HF transmitter or transceiver kits or portable / emcomm kits.
I have now modified the latest version 1.1 to eliminate surface mount components. The surface mount load resistors have been replaced with a single TO-220 packaged 50 Ohm 30W resistor with a heat sink. The new revision is still in testing and should be available in January 2019.
Other features include:
- Compact size – 145mm x 65mm (PCB) with corner mounting holes
- BNC, SMA or direct wired input/outputs
- Tuner bypass switch
- Switch selected Internal 50 Ohm 30W load
- Pi Network tuner configuration for wide range tuning into loads less than or greater than 50 Ohms
- 12 position inductor switch with all inductors capable of 2.5A RMS RF
- 2 380pF Air variable capacitors with 500V max voltage rating
- Can be purchased as a kit or assembled. Some surface mount soldering required.
- Note: Knobs not included
|Dimensions||3 × 6 × 2 in|
Bare Board, Kit, Assembled