so ive been putting this off for like two years but i finally got around to building a proper 40m dipole from scratch instead of just running my old whip with a tuner. cut two legs of 33.3 feet each off some 14awg stranded wire i had in the garage, used a SO-239 chassis connector i had in the junk box for the feedpoint, and soldered the whole thing up with a little chunk of thick pvc pipe as the center insulator. drilled two holes through it and sealed with some self-amalgamating tape.

hung it inverted-V style from a 30 foot mast i cobbled together from some telescoping fiberglass poles, legs going out at roughly 45 degrees. fed with about 50 feet of RG-8X down to the shack.

heres the thing — my SWR is reading around 1.8:1 at 7.150 and it kind of dips to about 1.5 near 7.200. i was expecting to get closer to 1.2 or so. tried trimming a few inches off each side but it barely moved. i checked my connections look good and the solder joints are solid. any ideas whats throwing it off? i'm wondering if the angle of the legs is affecting the feedpoint impedance more than i thought, or maybe its the coax acting up. the coax has been outside for a while and i never put a drip loop on it which i know i should have done.

the inverted-V configuration will do that, yeah. when you bring the legs down at 45 degrees the feedpoint impedance drops below the standard 72 ohms you'd get from a flat dipole — can land anywhere from 50 to 65 ohms depending on the angle and height, so 1.8:1 on 50 ohm coax honestly isnt bad at all. some guys put a 1:1 choke balun right at the feedpoint which can help clean things up a bit and also stops common mode current on the braid which might be part of whats messing with your readings. i built a 20m version of basically the same setup last spring and had similar numbers, threw together a quick ugly balun with a bunch of RG-8X wound on a paint can lid and it dropped down to 1.3. also worth checking if theres any water getting into that SO-239 — even a little moisture in there will do weird things to your readings especially on transmit.

honestly 1.8 is totally workable, most rigs will tune that no problem and youre not losing that much power. the coax without a drip loop worries me more long term, ive ruined two runs of coax that way. just a simple U-bend before the connector going up and duct tape it or whatever, takes five minutes. also what are you using to measure SWR, a standalone meter or the rigs built in one? the built in ones on some radios can be a little optimistic or just kinda vague in my experience.