N7DDC designed the popular “ATU-100” 100 watt antenna tuning unit (ATU) which is freely available as a kit or even in built up form, from vendors such as eBay, Aliexpress and others. N7DDC’s QRP ATU-10 is based on his other work of the ATU-100 but uses latching relays for lower power consumption and battery use.
VK3PE done a redesign. Changed the PIC devices (PIC16F1454 and PIC16F18877) to a larger easier to solder footprint and actually still available from a number of suppliers. As well changed the footprints to solder 0805 parts in place of the 0603 size.
For more information on the N7DDC ATU-10 is here. http://www.carnut.info/ATU_N7DDC/ATU-10/ATU-10%20build.html.
Or, the ATU100 Groups.io Group.
Or see pdf.
Attached a view pics of my own build.
Below the ATU the small backback for the 3.7V/2600mAh LIPO. For leftover PCB´s see PCB swap meet
