so i've been wanting to do this for probably two years now and last weekend i finally got off my butt and did it. built a little bitx40 style single band 40m rig, nothing fancy, mostly followed the schematic but swapped out a few caps i had in the junk box. runs about 4-5 watts out which honestly i wasnt sure would be enough to do anything useful.

took it to the state park about 20 minutes from my house, just threw a wire up in a tree maybe 25 feet or so, used my kx2 paddle and a little battery pack i had from an old flashlight project. sat there for about an hour and a half and made 11 contacts, two of which were out to colorado and one guy in ontario. im still kind of amazed that worked.

the rig runs warm but not scary hot. i did notice some spurious output that i want to look at with the scope before i take it out again, and the sidetone is a little weird — like it dips in pitch when i send longer dashes? not sure if thats a keyer thing or something in the audio chain. but overall for a first scratch build i'm pretty happy. anyone else doing a lot of portable QRP these days? curious what kind of antennas people are using in the field.

that sidetone pitch shift on longer dashes is almost certainly a power supply sag issue — your battery voltage is probably drooping slightly under the TX load and since the sidetone oscillator is probably sharing that rail it follows the voltage down. easy fix is either a small cap across the supply at the board or a separate regulated rail for the audio section if you have room. either way nothing to worry about operationally, it's not affecting your RF output.

11 contacts in 90 minutes with a homebrew rig at 5 watts is a solid afternoon. colorado and ontario on 40m in the afternoon is decent propagation work too, not a gimme. once you get that spurious sorted out you'll be in good shape. have you thought about adding a low pass filter if you dont already have one? even a simple 5 element chebyshev will clean things up considerably and takes maybe 30 minutes to wind.

man this is inspiring me to actually finish the rock mite i started like 18 months ago and then shoved in a drawer. i keep telling myself i'll get back to it. what did you use for an enclosure? that's always where i get stuck, i can do the electronics fine but then i spend forever agonizing over how to box it up.