so i've been sitting on my little uBITX for about 6 months now, just using it at the home shack with a proper antenna and a decent power supply, never really pushing it hard. this weekend i finally threw it in a backpack with my end fed half wave and a little 3ah lipo and hiked out to the ridge near my house.

honestly wasnt expecting much. i've heard people say QRP is frustrating and you just sit there calling CQ into the void but that wasnt my experience at all. worked 4 contacts on 40m in about an hour and a half, including one guy in michigan (im in colorado) which felt pretty good for 5 watts. the band was decent, nothing crazy.

the one thing i was NOT prepared for was just how much the antenna placement matters when you dont have a big yard to spread things out. i had to kind of compromise on the feedpoint height and i think i lost some efficiency there. also the lipo ran down faster than i expected, might have been the cold. its been bugging me ever since whether i should switch to a different battery chemistry for cold weather ops.

anyway, just wanted to share. if anyone has experience with cold weather battery stuff or just QRP portable in general i'd love to hear what works for you.

Michigan to Colorado on 5 watts on 40m is a solid contact, don't undersell that. The band does a lot of the work but you still gotta have a decent signal to pull it off.

On the battery thing — yeah LiPo does not love the cold. I switched over to LiFePO4 chemistry a couple years back and it holds up way better below freezing, trades a tiny bit of energy density for much better temperature performance. Also safer if you're throwing it in a pack. I use a Bioenno 4ah pack and it's been reliable. Little heavier than a lipo of the same capacity but worth it for winter stuff.

The antenna height thing is real. I've started carrying a 10m fiberglass pole on longer outings just so i can actually get my feedpoint up where it belongs. Makes a noticeable difference, at least to my ears.

ive been wanting to do this exact thing but i keep putting it off because i built my QRP rig from a kit and im honestly not confident its putting out a full 5w. like i have no way to verify it without a wattmeter which i dont have. does anyone just go for it without measuring or is that dumb