so i finally finished my first real scratch build, a 40m single band CW rig loosely based on the pixie design but i swapped out a few components and added a small audio filter stage because the pixie's audio was driving me nuts. took me about three weekends of fiddling around on the bench and one magic smoke incident with a transistor i wont name out of shame.

been running it at about 500mW into a wire dipole hung between two trees in the backyard and i made contact with a station in ohio last tuesday, im in virginia, so not a huge distance but still pretty cool for half a watt. the CW is a little chirpy still and im not totally sure why, might be the VXO drifting or just my power supply being noisy, havent tracked it down yet.

anyway just wanted to share because i was pretty skeptical QRP would be worth the effort but its kind of addictive now. thinking about trying to do a SOTA activation with it once i figure out the chirp situation. anyone built something similar and dealt with chirp on a simple VXO rig?

congrats on the build, chirp on VXO rigs is super common and usually comes down to a few things. most of the time its the keying — if youre hard keying the PA stage directly the supply voltage is drooping for a split second when the key goes down and that pulls the oscillator frequency with it. try decoupling the oscillator stage more aggressively, like a separate RC filter or even a small 78L05 just feeding the osc. also check your key waveform if you have a scope, really fast rise times make chirp worse and adding a little shaping network helps a lot. the other thing is physical stability, even small vibrations from a fan or bumping the bench can make a crystal VXO wander around. but honestly 500mW to ohio on a homebrew rig is solid, dont let the chirp discourage you

I did a pixie build last year and had the same chirp issue, drove me absolutely crazy for a while. ended up being my power supply which was a cheap switching wall wart and it was just injecting noise into everything. switched to a battery and it got way better, not perfect but definitely better. for SOTA that actually works in your favor because youll be on battery anyway. the pixie type rigs are pretty sensitive to all that stuff but theyre fun to build. what did you use for the audio filter stage? im always looking for ideas to clean up the audio on simple rigs like that