so i finally finished my first scratch built QRP rig, been putting it off for about two years because it seemed intimidating but honestly it wasnt that bad. built a 40m CW transceiver based on a design i found in one of the older QST issues, running somewhere around 4-5 watts out. got my first contact with it last tuesday night into ohio from here in virginia which i was pretty happy about given the conditions lately.

anyway i have a couple questions for people who do this regularly. first off im getting a little bit of key click that i didnt have with my commercial rig, not sure if thats something in my keying circuit or if its just par for the course with homebrew stuff. second thing is the whole efficiency question — im using a 7805 regulator to drop from 12v down to the supply voltage and i know that thing runs pretty warm. someone at the club mentioned i should look into a switching regulator instead but i dont really know where to start with that. is it worth the hassle for portable ops or am i overthinking it

congrats on the first build, that ohio contact is solid especially right now. the key click thing is almost certainly your rise and fall time on the keying waveform — if its clicking youre probably switching too fast. most homebrewers add a small RC network on the keying line to soften that up, like a resistor and cap that shapes how quickly the envelope comes up. theres a pretty good explanation of it in the ARRL handbook if you have one handy, or just search for QSK keying shaping and youll find what you need.

on the 7805 question, yeah for portable work that linear regulator is basically throwing away voltage as heat which eats into your battery runtime. a buck converter module is honestly not that complicated to drop in, you can get adjustable ones for a couple bucks and most of them are pretty clean electrically though you might need to add some filtering if you notice any noise on receive. for home use i wouldnt bother but if you're running off a lipo or something in the field it makes a real difference over a few hours.

im in a similar spot, built a little pixie kit a while back as kind of a stepping stone before doing a full scratch build. havent done anything that ambitious yet but this is making me want to try. what design did you end up using from QST, was it one of the older ones or something more recent? i feel like there are so many options and i keep getting paralyzed trying to pick one to start with