so ive been putting off building my own antennas for way too long, always just bought pre-made stuff or used a buddipole when i was portable. finally sat down this weekend and built a simple 40m dipole out of some 14 AWG stranded wire i had laying around in the garage.

cut each leg to about 33.5 feet going off the standard 468/f formula, soldered up the feedpoint to a SO-239 i pulled off an old dummy load chassis, and hung it up inverted-V style with the apex at about 30 feet off a tree branch. center support is just a piece of PVC with a hole drilled through it, nothing fancy.

SWR at the bottom of 40m is around 1.4:1 which honestly surprised me in a good way, but up around 7.250 it climbs to like 2.8:1 and my rig starts complaining. i havent put a choke on the feedline yet, which im guessing might be part of it? or do i just need to trim the legs a little? the wire is insulated if that matters, i know that changes things slightly compared to bare wire.

also wondering if anyone has strong opinions on using a 1:1 balun vs just a coax choke at the feedpoint for a basic dipole like this. ive read like 50 different forum threads and opinions seem all over the place on this one.

the insulated wire is almost certainly why your resonant point is off — insulated wire has a velocity factor less than 1 so it behaves electrically longer than its physical length. rule of thumb is you usually need to trim a few inches per leg compared to bare wire, sometimes more depending on the insulation thickness. i wouldnt be surprised if you need to take 3-4 inches off each side to pull resonance up toward the middle of the band.

on the balun question, for a basic dipole fed with coax i usually just go with a few turns of coax wound into a choke right at the feedpoint, works fine for most situations and costs you nothing if you have extra feedline. a good 1:1 current balun will do the same job more predictably especially if youre running higher power but honestly for casual HF operation either way is fine. the common mode current thing is real though, if you skip it entirely you might find your SWR changes when you touch the coax or your audio picks up RF. learned that the hard way on my first dipole back in the day.

2.8:1 at the top of 40 isnt terrible, most rigs will handle that okay with their internal tuner if they have one. but yeah trim the legs and see where you end up, sounds like the insulation is making it read long. i use bare wire whenever i can just to avoid all that fussing around with velocity factor.

also 30 feet for the apex on an inverted-V is on the lower end, if you can get it higher you'll probably see a noticeable difference in your takeoff angle which matters for DX. not saying it wont work, just something to think about if you have a taller tree nearby.