so i finally got around to building a proper 40m dipole instead of using that random wire ive had strung up forever. cut each leg to roughly 33.5 feet based on the 468/f formula, used some 14 gauge stranded wire i had leftover from a house project, and fed it with RG-8X through a basic 1:1 choke balun i wound myself on a FT-240-43 core.

hung it as an inverted V with the apex at about 35 feet off an old pine tree and the ends tied off to fence posts. got it tuned pretty well across most of the band with the MFJ-259 showing around 1.4:1 at 7.150 which im happy with. but the feedpoint situation is bugging me a little — i just used a PL-259 chassis connector in a project box with some silicone around the edges. it rained pretty hard sunday and i noticed some weird readings afterward, wondering if moisture got in or if thats just normal variation with weather changes.

also curious if anyone has opinions on weatherproofing the feedpoint better, i've seen people use self-amalgamating tape but also coax seal and im not sure which is worth the effort

the weather affecting your SWR readings is pretty normal to be honest, especially with wire antennas. a wet rope or wet tree branch near the wire can detune things a bit and you'd see that on the analyzer. that said if moisture actually got into the feedpoint that's a real problem over time, corrosion will eat your connections and you'll be scratching your head six months from now wondering why things went south.

i've been using self-amalgamating tape for years and it's really the way to go at the feedpoint, coax seal is kinda messy and harder to remove when you need to redo connections. what i do is wrap the SO-239 and the first few inches of coax together, then a layer of self-amalgamating, then a layer of regular electrical tape over that to protect the self-amalgamating from UV since that stuff degrades in sunlight eventually. also make sure your project box itself has a drain hole at the bottom so if any water does get in it can get back out, sealed boxes can actually trap moisture worse than open ones sometimes.

1.4:1 on 40m with a homebrew dipole is perfectly fine, dont chase a 1:1 SWR, the feedline loss at that ratio is basically nothing.

yeah the self amalgamating tape is what everyone recommends and it works good. one thing i'd check too is whether your choke balun is actually doing its job — sometimes common mode current on the feedline can make SWR readings look weird and inconsistent especially when conditions change. did you do any measurement on the balun when you wound it or just go by the turn count? im not saying thats the issue just something to rule out.