Pititico, QRP CW transceiver designed by PY2OHH. One of the smallest and simplest transceivers designed around a single 2N2222 transistor. The power output is around 350 to 700mW most of the time, depending on the transistor and the crystal used. The space for L3 was designed so you could fit a T37 size toroid. You can also use an axial inductor placed vertically. The PCB design and schematic are updated to fix the harmonics suppression issue of the low pass filter ( still not perfect but more decent now ). The 2N3904 transistor was replaced with a TO18-3 2N2222A ( metal can ) so you can also use a heatsink for the transistor ( you MUST use one ). See the details in the BOM regarding C7*. The transmitter can also be modified for other bands but I prefer the 40m band ( best results ).