so ive been wanting to get off the cheap whip i bought when i got my ticket and actually build something real. decided to try a basic 40m dipole, just some 14 gauge stranded wire i had laying around from an old extension cord job. used the 468/f formula and came out to like 33.2 feet per side which felt right to me.

strung it up between the chimney and a tree in the backyard, probably 20 feet off the ground at the feedpoint which i know isnt ideal but thats what i had. coax down to the shack, put my analyzer on it and the resonant point is coming in around 7.4 MHz instead of the 7.15 I was shooting for. so its too short? or is 7.4 close enough that the environment is just pulling it a bit. i thought shorter wire meant higher frequency so i feel like i need to add wire but then the SWR is actually not terrible at 7.4, sitting around 1.4:1 which my tuner can handle easy.

not sure if i should bother trimming or adding or just leave it and use the tuner. kind of proud that it actually works at all honestly

yeah your instinct is right, higher frequency means the wire is electrically too short, so you'd need to add a bit to each side to pull it down toward 7.15. the 468 formula is a starting point but wire type, insulation, proximity to trees and other objects all affect velocity factor and end up shifting things. stranded insulated wire especially tends to load a bit so you might not need to add as much as the math says.

what i usually do is add a few inches at a time to each side and keep checking with the analyzer. tedious but you get a feel for it pretty quick. that said if your tuner handles it fine and you're not running a ton of power or contesting or anything, leave it. plenty of guys just let the tuner do the heavy lifting on a slightly off-resonance dipole and work the world just fine. 1.4:1 with a tuner at 7.15 is not gonna be your problem, your feedline loss and low height are bigger issues to worry about first honestly.

i had almost the exact same thing happen with my first 20m dipole, ended up resonant like 400 khz high and just left it for months before i bothered fixing it lol. the tuner thing works but once i actually trimmed it to where i wanted it the difference was noticeable, at least to me. could be placebo who knows

also 20 feet is low for 40m, youre gonna get more of a cloud warmer pattern than anything useful for dx but for regional stuff and nets it'll work fine. good first build though, way better than staying on a rubber duck forever