so i finally got around to building a simple 40m dipole out of some 14 gauge stranded wire i had in the garage. cut each leg to about 33.5 feet based on the 468/f formula, used a SO-239 chassis connector as the feedpoint center, and fed it with some RG-8X i had lying around. hung it up in an inverted-V config with the apex at maybe 25 feet off the ground off my back fence post.

problem is the SWR at 7.150 is sitting around 2.1:1 and i cant figure out why. i double checked the math and the connections look solid. the legs arent exactly equal in height on each side because of how the yard is shaped, one side is probably 5 feet lower than the other. could that be messing with the resonant frequency or is this just normal for an inverted-V? ive been reading conflicting things and honestly getting a little confused by all of it.

also not sure if the coax length matters here, its about 47 feet total run back to the shack. using an LDG tuner so i can get it flat but wanted to understand what was going on before i just let the tuner do all the work

2.1:1 on a homebrew dipole is honestly not bad for a first build, dont stress too much. the inverted-V configuration does affect the feedpoint impedance a bit compared to a flat-top, the angle of the legs changes things. if your legs are drooping at like 120 degrees or less you can expect the impedance to drop from that classic 73 ohm ballpark down closer to 50, which actually helps match to coax better in theory but the resonant point shifts too.

the unequal leg heights probably arent your main issue, the antenna will still radiate fine just with a slightly asymmetric pattern nobody will notice on 40m. id just start lengthening or shortening the legs a few inches at a time and see where the SWR dips. also check that your SO-239 connections are clean, i once chased a weird SWR for two days and it was just a cold solder joint at the feedpoint. coax length at 47 feet shouldnt matter with RG-8X youre not dealing with significant loss there.

yeah what he said about the inverted-V changing impedance is real, i went through the same thing with my first 20m build. one thing i'll add is that proximity to your fence post and any nearby metal or the ground itself is going to pull the resonant frequency down a bit from what the formula predicts. 468/f is really just a starting point in free space, real world installations almost always come out a bit long. try trimming maybe 3-4 inches off each leg and remeasure, bet it moves in the right direction.