so i finally got around to building a dipole for 40 meters after running a random wire forever and honestly should have done this years ago. cut it to length using the 468/f formula, ended up around 66 feet total, split in the middle with a SO-239 chassis connector i had in the junk box. used 14 gauge stranded wire from the hardware store, nothing fancy.

the thing actually tunes up pretty well across most of the band but i noticed SWR climbs up past 2:1 toward the high end of 40. i was expecting that but now im second guessing whether my feedpoint connection is actually the problem or if thats just normal dipole behavior. the solder joints look ok but i rushed the weatherproofing, basically just wrapped it in self-amalgamating tape.

should i be worried about the feedpoint or just live with it and use the tuner? also curious if anyone has done a fan dipole to cover 40 and 20 with the same feedpoint, ive seen it mentioned but never tried it

the SWR rising toward the high end of 40 is pretty normal for a straight dipole, especially if its cut for the low end or CW portion. nothing wrong with your feedpoint probably. the 468 formula is a starting point and actual resonance depends on height above ground, what its near, wire type, all that. i usually cut long and trim, gives you room to work with.

self-amalgamating tape is fine for weatherproofing as long as you stretched it properly and got good overlap. where it tends to fail is if moisture got in before you taped it or if the connector itself wasnt sealed around the shell. coax seal putty over top of the tape is cheap insurance if you're worried about it.

fan dipoles work great, done a few of them. the elements do interact a bit so you usually end up trimming each leg slightly shorter than you'd expect from the formula alone. just takes a bit of fiddling but nothing too painful. worth doing if you want 20m without dealing with the tuner.

yeah i built almost the exact same thing last summer, same wire from home depot, similar connector setup. mine sits at about 30 feet at the feedpoint and the 2:1 point is right around 7.250 or so which covers everything i care about for phone. i wouldnt stress the high end SWR too much unless you're trying to do FT8 up near 7.074 consistently, in which case just trim a little off each leg and see where it lands.

one thing i did differently was use an actual center insulator piece from a kit i had lying around, made the whole thing feel a lot more solid mechanically. your chassis connector will probably be fine but keep an eye on it after a few rain cycles, sometimes they corrode at the solder joint where you cant see it.