so i've been putting this off for like two years and finally just did it last weekend. cut a 40m dipole out of some 14 AWG stranded wire i had laying around in the garage, used a SO-239 chassis connector i pulled off an old project as the center insulator — well, i basically just drilled two holes through a chunk of PVC pipe i had and ran the wires through, soldered to the connector pins. its not pretty but it works.

anyway hung it inverted-V style from a tree in the backyard, about 35 feet at the apex. got it trimmed to resonate right around 7.150 and the SWR is sitting around 1.4:1 at the low end and creeps up to about 2.1:1 toward 7.300. fed with about 50 feet of RG-8X into the shack.

my question is about the feed point situation — i just tied off the coax with some electrical tape to keep the strain off the connector but im a little worried about water getting in there over time. what do people usually use to weatherproof that center section? i've heard self-amalgamating tape is the way to go but also heard people use coax seal or just silicone. also wondering if my SWR curve is normal for an inverted-V or if i should keep trimming.

that SWR spread is pretty normal for an inverted V, the angle of the legs affects the feed impedance and you're not going to get a perfectly flat curve across the whole band without a tuner or some matching network. 1.4 to 2.1 across 40m is honestly fine, most rigs will handle that without blinking.

for weatherproofing i've tried pretty much everything over the years and the self-amalgamating tape is genuinely the best option if you do it right — start below the connector and work your way up overlapping by half the tape width, then come back down over it again. the stuff fuses to itself and you get a waterproof seal that also flexes a bit when the antenna moves in the wind. coax seal is messy and gets everywhere when you eventually need to undo it, and plain silicone has a tendency to peel away from smooth surfaces after a season or two. the self-amalg stuff is maybe $5 at the hardware store or online and a roll lasts forever.

also — if that PVC chunk is sitting outside exposed to UV it will get brittle and crack eventually. not a huge deal but worth keeping an eye on or painting it with some krylon fusion if you want it to last more than a couple years.

nice work getting it up. i did almost the exact same thing for my first antenna except i used some kind of mystery wire i bought at a hamfest and spent way too long trying to figure out why it kept changing resonance on me — turned out to be stranded steel inside, not copper. lesson learned.

the coax seal stuff works but yeah its a pain when you need to get back in there. i use the self-amalgamating tape now too and honestly havent had any issues with it.