so ive been working on this 40m crystal controlled TX for the past few months, mostly following the EMRFD designs with a few modifications because i couldnt source the exact parts listed. got it to fire up finally last week and it puts out somewhere around 3-4 watts into a dummy load which honestly is better than i expected.

the problem is there's this weird chirp on keying, like the frequency drifts for maybe half a second when i first hit the key and then settles. i thought it was a VFO stability thing but its crystal controlled so that shouldnt really be happening. also the sidetone is a bit off, sounds slightly different pitch than what im actually transmitting which is annoying but whatever, livable.

anyone dealt with the chirp thing before? im wondering if its a keying voltage issue affecting the oscillator stage somehow, or maybe my buffer amp isnt isolating well enough. the crystal is a surplus 7.030 i pulled out of an old piece of gear so maybe that has something to do with it too.

the chirp is almost definitely a keying issue yeah. if youre hard keying the oscillator directly thats gonna cause exactly what your describing — the crystal takes a moment to stabilize under load and you get that frequency wobble at the start of each element. the classic fix is to key the PA stage instead and let the oscillator run continuously. if you want to keep keying the osc for some reason you can add a small delay circuit but honestly its more hassle than its worth.

also check if your supply voltage is drooping when you key. even a small sag on the oscillator B+ will pull the frequency a bit. ive seen this cause chirp on otherwise solid rigs, took me forever to figure out the first time. a good bypass cap right at the oscillator and a separate regulated rail for that stage usually sorts it out.

had the same chirp problem on a 20m transmitter i built last year, drove me crazy for weeks. turned out my buffer stage didnt have enough isolation and the PA loading was pulling back through into the oscillator. ended up adding another stage between them and it cleaned right up. the sidetone pitch thing is probably just your monitor oscillator running at a slightly different frequency, not really a problem unless it really bugs you — some guys actually prefer that so its easy to distinguish the monitor from the actual signal.