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Solar
SFI 201
SN 126
A 14
K 1 Quiet
X-Ray C4.3
Wind 398.1 km/s
Aurora 1
Updated 11:30 UTC HamQSL · N0NBH
Day 80/40m Poor 30/20m Good 17/15m Good 12/10m Good
Night 80/40m Good 30/20m Good 17/15m Good 12/10m Poor

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first homebrew dipole — got it working but SWR is still weird on 40m

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so i finally built my first dipole from scratch, been putting it off forever because i kept thinking it would be more complicated than it is. used some 14awg stranded wire i had laying around from an old electrical project, cut it to roughly half wavelength for 40m which came out to about 66 feet total, 33 feet each side. center insulator is just a piece of PVC i drilled holes through and the ends are tied off with some nylon rope to trees at maybe 25 feet up — its not perfectly flat, kinda droops in the middle which i've read is fine.

fed it with RG-8X down to the shack and when i check it on the analyzer it shows SWR around 1.4:1 at 7.150 but then it climbs pretty quick toward the band edges, like 2.8:1 at 7.000 and maybe 2.5 at 7.300. resonant point seems to be around 7.2 which is close enough i guess but i thought it would be flatter across the whole band. is this just what a dipole does or did i screw something up with the feedline length or maybe the height is hurting me. the antenna is also slightly sloped because one tree is taller than the other, not sure if that matters.

overall though it actually seems to work, made a bunch of contacts yesterday including one into ontario which felt pretty good for a wire antenna ive never made anything before.

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yeah thats pretty much just what a dipole does, 40m is a wide band and a resonant half wave dipole isnt going to cover all of 7.0 to 7.3 with flat SWR unless you're running something like a fan dipole or a trap setup. 1.4 at your resonant point is honestly really good for a first build especially with stranded wire and a field expedient center insulator. the slope probably shifts resonance a little and changes the pattern somewhat but nothing to worry about. your tuner should handle the band edges just fine if your radio has one, and even without a tuner most rigs wont care about 2.8:1 as long as its consistent and not bouncing around.

the Ontario contact kind of proves it works, 40m wire antennas punch above their weight especially at night. if you want to flatten it out eventually you could try a 1:1 choke balun at the feedpoint, sometimes with coax you get common mode current issues that mess with the readings a bit.

the feedline length can actually affect what you see on the analyzer depending on where you're measuring from — if you're checking at the radio end of the coax rather than right at the feedpoint you might be seeing some transformation from the line itself. not always a huge deal but worth knowing. i ran into something similar with my 80m dipole and thought something was wrong for like two weeks before someone pointed that out to me. anyway 1.4:1 is fine, go make contacts

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