so ive been going back and forth on this for probably two months now and i need someone to just tell me what to do honestly. my situation is i have a decent sized backyard, maybe 80 feet end to end if i stretch it diagonally, and im trying to decide whether to put up a simple 40m dipole fed with coax or just do a vertical with a decent radial field. i already have a 33ft fiberglass mast from a previous attempt at a 20m vertical that didnt really go anywhere.

the thing is i mostly work local and regional stuff, some nets, occasionally try to get into some DX when conditions are right but im not like a serious DX chaser or anything. my noise floor here is pretty bad, suburban neighborhood, lots of switching power supplies and led lighting and whatever else the neighbors are running. ive heard dipoles can be a bit quieter on receive because of how they reject noise from off the sides but i dont know if thats actually significant in practice or just something people say.

height is going to be limited either way, probably 30 feet at best for the dipole center or the vertical top. am i overthinking this or does it actually matter that much at that height

you're not overthinking it but also at 30 feet on 40m you're not going to have a dramatically great antenna no matter what you pick, so honestly just pick one and live with it for a while. that said if noise is actually your concern the dipole is probably going to serve you better, the directional null really does help in practice, not just theory. i had a nasty noise source almost due west of me and rotating my doublet to null it out made a genuine difference. obivously you cant rotate a fixed dipole but you can orient it so the ends point toward your worst noise sources and get some rejection that way.

the vertical with radials will likely give you a lower takeoff angle which is better for DX but you said youre not really chasing DX hard so that probably doesnt matter much. also laying a decent radial field is more work than people expect. 16 radials minimum if you want it to actually perform, 32 is better. if the ground in your yard is anything like mine (clay with rocks) it's a whole afternoon of work.

had basically this exact debate last spring. went with the dipole inverted-v style off the 33ft mast and honestly it works fine for what i do. the noise thing is real, my neighbor two houses down has something that makes a terrible buzzing on 40 and i can actually point the antenna to null it a bit. not perfect but noticeable.

one thing though — if you go inverted-v make sure your apex angle doesnt get too shallow or the feedpoint impedance starts drifting and it gets harder to match. i keep mine at like 120 degrees or more and it loads up pretty cleanly on my tuner. anyway just build both eventually, wire is cheap