so ive been putting this off for way too long but i finally bought a spool of 14 AWG stranded copper and im going to try building a simple 40m dipole this weekend. i have a decent enough backyard to hang it inverted-V style from a tree that's maybe 35 feet up at the center, legs running down at probably 45 degrees or so, which i know isnt ideal but it's what i've got.

my question is mostly about the feedpoint. ive seen people use those cheap center insulators from the usual suppliers and ive also seen guys just use a PL-259 chassis mount connector epoxied into a short piece of PVC pipe or whatever. does it actually matter that much which way you go? like is one significantly better than the other for a basic HF antenna? i feel like im overthinking this but i dont want to do it twice.

also — the formula i keep seeing is 468 divided by frequency in MHz which gives total length in feet. for 40m i was thinking 7.150 as my design frequency so that comes out to around 65.5 feet total, so each leg would be about 32.75 feet. does that sound right or am i missing something. i have an MFJ-269 so i can tune from there but id like to at least start close.

your math is right, 468/7.15 gets you there. one thing i'd say — cut each leg a little long, maybe an extra foot on each side, and trim from there. way easier than trying to splice wire back on if you go too short. with stranded 14 AWG the velocity factor is close enough to solid that it wont make a meaningful difference at those frequencies.

on the feedpoint question, honestly either works fine. ive used both over the years. the PVC homebrew thing is perfectly serviceable and probably more weatherproof if you do it right with some self-amalgamating tape over the connector. the cheap plastic center insulators are fine too but the cheaper ones can get brittle in UV after a couple seasons. if you're already building from scratch id just go the PVC route, costs basically nothing and you get to say you built the whole thing yourself which is half the fun of it anyway.

inverted-V on 40m from 35 feet is going to work fine. you'll have a slightly higher angle of radiation vs a flat top but for anything within a few hundred miles its actually decent and the lower impedance makes it a bit easier to match. have fun with it.

yeah cut long and trim is the way to go, learned that lesson the hard way on my first 20m dipole lol. also dont forget to account for the center insulator thickness in your overall measurement, its minor but if you're trying to be precise it adds up. my first one i just zip tied the coax to the center and it lasted two years before the connector started acting up, so even the janky approach works for a while.