so i finally pulled the trigger and built one of those QRP Labs QCX mini kits for 40m and honestly i wasnt expecting much but the thing actually works. got it all assembled over a weekend, smoked one resistor because i was being impatient with the iron but otherwise pretty smooth build. fired it up and immediately heard a pile-up on some DX station which was a good sign i guess.

anyway i managed to work a station about 340 miles away running 4 watts and i was completely hooked. my question is more about efficiency i suppose — im using a random wire in the attic right now with a tuner and im wondering if thats killing my effectiveness. i know QRP is already uphill, the last thing i want is to waste half my power in a mediocre antenna situation. also wondering if anyone has tips on operating strategy, like when to call, when to give up, that kind of thing. i feel like with 100 watts you can just throw RF at a problem but with 4 watts you have to actually think a little

welcome to the rabbit hole ha. your instinct about the antenna is exactly right — at QRP power levels the antenna is basically everything. a random wire in the attic isnt terrible but if you can get anything outside and elevated youll notice the difference immediately. even a simple dipole out a window makes a real difference. the feedline losses matter too, if youre running coax any length make sure its decent quality because at 4 watts you really cant afford to be dumping a watt into lossy coax.

for operating strategy honestly the biggest thing i learned is timing and band conditions. check the solar indices before you sit down, a bad day on 40m with QRP is just frustrating. also dont be afraid to call a station multiple times if conditions seem good but spread your calls out and listen carefully between them. and CW is your friend if you havent already gotten into it — those narrow filters and the way the human ear pulls CW out of noise is like having a free 10dB advantage over SSB.

340 miles on 4 watts is solid, dont undersell that. i had a similar experience with my first QCX build last year, there is something about making a contact with a rig you built yourself that just feels different. i couldnt really explain it to my wife but i tried lol.

one thing i do now for portable and home operation is keep a little log of what worked and what didnt, like what time of day, which part of the band, stuff like that. after a few months you start to see patterns specific to your location and setup which helps a lot more than generic propagation advice. also have you tried the QRP watering holes like 7.030 for CW? theres usually activity there and people calling there generally expect QRP stations so theyre a bit more patient about asking for repeats.