so i finally got around to building a proper wire dipole instead of just using that crappy j-pole i've had for years. cut it for 40m using the standard 468/f formula which gave me about 66 feet total, 33 each side. strung it up in an inverted V configuration with the apex at around 30 feet off a tree in the backyard.

the problem im having is at the feedpoint — i just twisted the coax center to one leg and shield to the other, wrapped it in self amalgamating tape and called it a day. SWR is reading around 1.8:1 at 7.150 which honestly isnt terrible but i was expecting it to come down a bit more. wondering if the feedpoint connection itself could be causing issues or if this is just normal variation from the inverted V geometry dropping the impedance a bit. also should i have used a 1:1 balun here? i didnt and now im second guessing that decision every time i see the shield getting warm after a long transmission.

any advice from people who've actually built these things appreciated, im running about 100w and the antenna seems to be working but something feels off

1.8:1 on an inverted V is actually pretty reasonable, especially at that apex height. the angle of the legs changes the feedpoint impedance from the theoretical 73 ohms of a flat dipole — depending on how steep your V is you can end up anywhere from 50 to maybe 65 ohms, which is why it's matching up better than you'd think. the 468 formula is a starting point too, real wire with real insulators in a real environment is gonna need some trimming.

on the balun question — yes, you should put a 1:1 choke balun or at least a few turns of coax wound up at the feedpoint. what you're describing with the shield getting warm is common mode current running back down the outside of the coax and that's not just inefficiency, it can cause RF in the shack and mess with your SWR readings. i built a simple air-core choke for mine, just wound about 8 turns of the coax itself in a coil about 6 inches in diameter right at the feedpoint. worked a treat and the shield stopped getting warm almost entirely. dead simple and costs nothing if you have spare coax.

yeah the balun thing is real, i skipped it on my first dipole too and then spent like two weeks wondering why my swr was bouncing around depending on where i put my hand near the feedline. turned out it was common mode the whole time. just wound some coax into a coil at the feedpoint like the other guy said and fixed it immediately, felt kind of dumb but whatever

also double check your connections arent just twisted together, that'll oxidize over time especially outdoors and resistance starts creeping up. i solder mine now and then seal everything. the self amalgamating tape is fine but make sure moisture cant get in at the ends