so ive been putting this off for like two months but i finally sat down last weekend and built a 40m center-fed dipole from scratch. used some 14 gauge stranded wire i had laying around from an old extension cord i stripped down, and a PL-259 connector i had in the junk box. center insulator is just a piece of pvc i drilled holes through and used some wire ties to secure everything. nothing fancy.

cut each leg to around 33.5 feet based on the 468/f formula for 7.150 which is roughly where i want to operate. havent put it up yet because im second guessing myself on a few things. first, the wire i used is stranded and i read somewhere that stranded vs solid can affect the resonant length slightly? im not sure how much that actually matters in practice. second, my feedline situation is kind of a mess — i only have about 35 feet of RG-8X to get from the antenna down to the shack and i dont have a 1:1 balun on hand. should i be worried about feedline radiation without one or will it mostly be okay for now just to get on the air and test it. i do have an MFJ-269 so i can check the swr before i connect anything to the radio.

the plan is to run it as an inverted V with the center at about 30 feet using my fiberglass push-up mast. ends will probably be at like 8-10 feet off the ground because thats just what the yard allows. open to any suggestions before i haul everything outside

stranded vs solid really isnt gonna make a noticeable difference at 40m, like were talking maybe an inch or two of electrical length at most, your analyzer will sort that out when you trim. dont overthink it.

the balun thing — honestly for just getting on the air and testing youll probably be fine without one especially with RG-8X and an inverted V. youll likely see some common mode current but at low power for testing it wont kill anything. that said if you already own one throw it on there, no reason not to. if the swr looks weird on the analyzer and you cant figure out why, that would be the first thing id add.

30 feet at the apex for an inverted V on 40 is decent. the low ends wont hurt you as much as people make it sound as long as theyre not like right next to a metal fence or something. run it, check it with the 269, trim as needed. you probably wont even have to trim much if your wire length is close.

i built almost the exact same thing last spring and had mine up as an inverted V too. one thing i wish i had done differently was make the legs a little longer than calculated and then trim down instead of cutting exact and hoping. its way easier to shorten than to splice more wire on later. i ended up having to do a janky splice on one leg and it bugs me every time i think about it even though it probably doesnt actually matter electrically.

also on the pvc center insulator — how are you sealing the holes where the wire goes through? i left mine open and after a few rain cycles moisture got in and i kept getting weird readings. a little silicone caulk or even electrical tape wrapped around it goes a long way. might be overthinking it but just something i learned the hard way