so ive been going back and forth on this for a few weeks now and figured id just ask here because the usual google rabbit holes arent helping. im putting up my first real HF antenna and the lot isnt huge — maybe 80 feet usable in one direction. i can get a 40m dipole up at about 25 feet if i use the house and a tree, or i could build a vertical with some radials in the corner of the yard.

everyone says dipoles need to be at half wavelength height to really perform but 25 feet is nowhere near that on 40. so is it even worth it over a vertical at that point? ive read that verticals radiate low angle which is good for DX but they also pick up more noise? my noise floor here is already kind of rough, S4-5 on a quiet evening. just want to work some decent DX and maybe some stateside stuff, not trying to win contests or anything.

also if i go vertical im thinking a homebrew quarter wave with maybe 16-20 radials on the ground, not elevated. is that enough or do i need like 60+ to make it competitive with the dipole

25 feet on 40m isnt ideal but honestly its not as bad as people make it sound. a dipole at that height is gonna have a higher radiation angle than you want for DX but itll still work, and the big thing you already figured out yourself is the noise. verticals really do pick up more local garbage in a lot of suburban setups. ive run both and the dipole at modest height usually wins for me just because im not fighting the noise floor the whole time.

on the radials question — 16 to 20 on the ground will get you most of the way there. theres some NEC modeling work that shows the improvement from 16 to 60 radials is maybe 1-2 dB at best, so unless youre a contester obsessing over every tenth of a dB its not really worth the extra wire and work. get them down, make them at least a quarter wave long, and youre fine. id still probably try the dipole first just because its cheaper and you can always add the vertical later.

yeah same boat as you a while back and i ended up doing the dipole just because it was easier to put up and take down if something went wrong. noise thing is real, my neighbor has some kind of switching supply that absolutely murders my S meter and the vertical made it way worse for some reason. dipole at 25 feet still gets me into europe on 40 most evenings around sunset so its not like its useless at that height