so i've been putting off building the QMX for probably six months now, just intimidated i guess. finally sat down last weekend and did it, took me about 4 hours spread over two evenings and honestly it went smoother than i expected. fired it up on 40m and immediately heard a pile up on some DX station which i thought was a good sign lol

anyway i made my first contact with it running about 4 watts into a simple end-fed and the other guy gave me a 559 which i was pretty stoked about. but i have some questions for people who've been doing QRP longer than me. first, how much does antenna really matter at these power levels -- like i know it always matters but does it matter MORE when youre only running 4-5 watts? and second, im having trouble deciding if i should try to squeeze more efficiency out of my current setup or just get comfortable operating QRP first before i start optimizing everything. also is 40m the best band to start on or should i be trying other bands

sorry for the scattered questions, just excited and have a lot to learn still

congrats on the build, QMX is a great little rig. to answer your antenna question -- yes, antenna absolutely matters more at QRP levels, probably more than anything else you can do. when youre running 100 watts you can kind of mask a mediocre antenna with brute force but at 4 watts every dB counts. that end-fed will work fine but if you can ever put up a dipole at a decent height or try a vertical with a good ground system you'll notice the difference pretty quick.

as for which band to start on, 40m is solid especially for regional stuff and in the evenings. but honestly 20m during the day when conditions are decent is where QRP really shines for me, i've had contacts across the atlantic running 5 watts and it never gets old. just watch the propagation forecasts, when the bands are cooperating QRP feels like magic and when they're not it can be frustrating. stick with it though, you'll develop a feel for it.

oh man i remember building my first kit, i built a little 40m pixie years ago and made my first CW contact and just sat there kind of stunned that it worked at all haha. your question about optimizing vs just operating -- i'd say just operate for a while first. i spent way too long tweaking stuff early on instead of just getting on the air and the operating experience taught me more about what actually needed improving than any amount of reading or fiddling. the antenna thing the other guy mentioned is spot on though, if you ever get a chance to compare your end-fed against something else back to back you'll see exactly what i mean