so ive been running a half wave dipole for 40m for about two years now, center fed with 450 ohm ladder line into a balanced tuner. its at about 25 feet which i know isnt ideal but its what the trees allow. been thinking about swapping to a vertical, probably a quarter wave with a decent radial field, partly because i want to try some low angle DX and the dipole at that height is basically just an NVIS cloud burner.

thing is ive read a lot of conflicting stuff. some people swear by verticals for 40 and 80 DX, others say unless you have like 60 radials and its over saltwater its not worth it. my yard situation means i could probably put down 20-30 radials but not much more than that. is there actually a noticeable difference in practice or am i chasing something that wont pan out

25 feet for a 40m dipole isnt doing you any favors for DX thats for sure, youre right about the NVIS thing. but i'd be careful assuming the vertical is automatically better. i put up a 43 foot vertical with 32 radials last spring and yeah the low angle stuff improved but i also picked up way more noise. the dipole actually had a quieter receive on a lot of bands which i didn't expect. for working europe from the midwest on 40 the vertical does seem to give me a bit of an edge on the signal reports but its not night and day. i think people oversell how much the radial count matters past a certain point — going from 16 to 32 i noticed almost nothing honestly. what matters more is that you get them on the ground and not floating in the air.

I've run both and honestly for 40m the answer is kind of "it depends on the path." The vertical wins on DX paths where you need that low takeoff angle but the dipole will smoke it on regional stuff and like you said 25 feet is actually pretty good for NVIS on 40 during the day. If I had to pick one setup and couldn't change it I'd probably keep the dipole and just raise it as high as possible rather than mess with a radial field. But if you have the real estate for the radials it might be worth the experiment just to see. You could always keep the dipole up and just add the vertical as a second antenna and switch between them — that's what I eventually ended up doing.