Pico Tuner Kit – End Fed Halfwave Tuner
Review video from Peter VK3YE – also check out his book!
End fed half wave antennas are understandably popular for portable operating. Our Pico Tuner is the smallest 10 Watt rated tuner for these antennas. The Pico Tuner is a single-band tuner that can be configured to operate on any frequency between 7 and 30 MHz (40 m – 10 m).
The Pico Tuner uses high quality components for low loss operation. Building is easy with clear online instructions. We also supply a test resistor to allow you to set up the tuner before attaching your antenna. The Pico Tuner uses an isolated link coupling arrangement with floating antenna terminals for best performance – as recommended by antenna expert Tom, W8JI. The Pico Tuner pcb incorporates strain relieved attachment points for the the antenna and, importantly, a counterpoise. We recommend a counterpoise length of 0.18 wavelengths. Unlike many 5 Watt end-fed tuners which use film dielectric capactitors, the Pico Tuner uses a rugged 200 Volt ceramic trimmer in parallel with a specially selected 200 Volt high Q surface-mount RF capacitor to give a 10 Watt rating – ideal for KX-3 users. Click here to download the instructions.
The Pico Tuner is designed to be fed with RG-174 co-ax and this is also strain relieved on the PCB.
This guide shows how to solder the 0805 capacitor – it is actually quite easy!
Don’t Miss Out on these Great Options
- Ready-made RG-174 co-ax cables.
- Antenna wire.
Power rating – 10 Watts
Bands – any single band 7 – 30 MHz.
PCB size – 18 x 57mm (0.7 x 2.25 inches)
Weight – 3 grams (<0.15 oz.) approx.
Ideas for Experimenters
- If you don’t like surface mount capacitors, you can use the test resistor holes to mount a leaded capacitor (not supplied).
- If building your Pico Tuner for 10-12-15 m you could leave out the 100pF capacitor and just use the trimmer. You will have to use more turns on the toroid to resonate it of course. As a start try 21 MHz – 22T, 24 MHz – 18T, 28 MHz – 16T. These values based on trimmer set half way (~25 pF).
- If you replace the toroid with a T50-10 mix (not supplied) and just use the trimmer, the Pico Tuner should work on 6 metres. Try 9 turns on the toroid as a start.
- While the Pico Tuner is designed as a single-band tuner, multi-banding is possible. I did the math and 12m-10m, 15m-12m, 17m-15m look possible (trimmer in parallel with 100pF). If you don’t install the 100pF SMD capacitor (or use a lower value padding capacitor) other possibilities arise.
- I have also included a second set of SMD capacitor pads on the Pico Tuner which would allow experimenters to install additional padding capacitance to allow the use of bands lower than 7 MHz. Bear in mind that in such cases, the tuning range will be reduced.