so ive been messing around with this for probably three months now, started with a kit from QRP Labs but then decided i wanted to do it from scratch because i learn better that way. anyway built a simple crystal controlled oscillator into a buffer stage then a class C PA, running about 2 watts into a dummy load right now. using a 7.030 MHz crystal i pulled out of an old clock radio which was probably a bad idea but it seems to be pretty close.

the thing that surprised me is how clean the signal came out, at least according to my spectrum analyzer (its a cheap nanoVNA hack thing not real test gear). harmonics seem to be down around 40-45 dB which i was not expecting from my first attempt at an RF PA stage. running about 12V from a bench supply, the PA transistor is a 2N3866 because thats what i had in the junk box.

my question is about keying it. right now im just grounding the key jack to cut off the oscillator stage but i get a horrible chirp on startup. like really bad. im guessing its a VXO drift thing as the crystal thermally stabilizes but im not sure how to fix it without completely redesigning the keying circuit. anyone dealt with this before with simple crystal rigs?

yeah the chirp on crystal rigs is almost always thermal but sometimes its power supply sag too. the classic fix is to key the PA stage and not the oscillator at all - let the osc run continuously and just gate the driver or the PA. you'll need a TR switch or at least a separate keying transistor on the PA but its worth it, the oscillator stays thermally stable and the frequency doesnt wander on every dit.

the 2N3866 is a solid choice for that power level by the way, seen a lot of homebrew stuff use that transistor and it handles abuse pretty well. if you do end up keying the PA stage make sure you put some thought into the key clicks too, a simple RC shaping network on the keying line makes a big difference on the air. 40-45 dB on the harmonics is honestly decent for a first build, clean it up a bit with a low pass filter and you should be fine for actual use.

what does your power supply look like when youre keying? i had almost the same problem with a 40m rig i built last winter and turned out it was the bench supply sagging like 200mV on keydown and the oscillator hated it. slapped a big cap right across the oscillator supply rail and most of the chirp just went away. probably not your whole problem but worth checking before you rebuild the keying circuit