so i finally got around to building a simple 40m dipole out of some #14 stranded wire i had laying around in the garage. cut each leg to roughly 33.5 feet, which i calculated from the old 468/f formula, and fed it with some RG-8X i had on hand. the center insulator is the part im not super confident about though. i just used a piece of scrap PVC pipe about 6 inches long and drilled holes through it to tie off the wire and attach the coax braid and center conductor. it seems sturdy enough but im wondering if there's a better way people do this or if the pvc will cause any issues long term, especially with UV exposure out here in arizona where things just kind of disintegrate if you leave them outside too long.

also the SWR came out around 1.4:1 at 7.150 which honestly surprised me, i expected to have to trim more. the whole thing is kind of an inverted V shape with the apex at about 35 feet up in an oak tree and the ends coming down to about 8 feet off the ground. running it into an old TS-570 and the tuner barely has to do anything which feels like a win.

anyone done anything clever for center insulators on homebrew dipoles? i see people talking about using SO-239 chassis connectors directly on the insulator which seems like a cleaner solution but also seems like it might let moisture in around the connector over time

PVC works fine honestly, plenty of guys run it for years without issues. the UV thing is real though, you might want to hit it with some krylon fusion or even just wrap it in self amalgamating tape to slow down the degradation. the gray electrical conduit fittings are a bit more UV resistant than the white plumbing stuff if you ever rebuild it.

the SO-239 idea is popular but yeah moisture is a legit concern if you dont seal it. i usually just put a couple wraps of coax seal around the connector body and then cover that with self-fusing tape and it holds up pretty well through midwest winters so arizona should be fine. the thing you want to avoid is water sitting in any cavity and then freezing or just slowly wicking into the coax braid over months. your RG-8X connection point is probably worth sealing regardless of what you do with the insulator, just slap some coax-seal on it and forget about it for a few years.

1.4:1 on a first build without trimming is actually pretty decent, i'd probably just leave it at that unless you're doing something where every tenth of SWR matters

i built basically the same thing last year for 40m and went through like three different center insulator designs before settling on just buying one of those cheap plastic ones from the big online ham vendors, think it was like $4. not the most satisfying homebrew answer but it had the SO-239 already mounted and drilled properly and honestly i spent way more time trying to reinvent that particular wheel than it was worth lol. the 35 foot apex inverted V should work great on 40, you might notice it has a slight preference in pattern toward the ends of the dipole but at that height and on that band it probably wont matter much for general operating