Current project is a 70cm dipole, which I don't think is done too often. :P
Yes, that's a plastic bottle cap in the middle. The lengths one goes to when one doesn't have a 3-D printer. :(
Finally got my 6m dipole working with a -43 voltage balun. Since I mistakenly cut it a little too short all those months ago, it resonated at the upper end of the 6m band, so I had to tack on a tiny loading coil to add some inductance and bring the resonant frequency down to where I wanted.
The unfortunate thing is that the loading coil also significantly cut the bandwidth of the antenna + voltage balun. At some point, I'll build a new dipole and not cut it as much. :P
Wow, that's a really good SWR curve. π
Now I just need a trimmer capacitor to allow me to choose what that bandwidth covers. π
J-pole is back and ready for action! And with my improvements since earlier, it's better than ever! :D
(I had to move it indoors because of exterior maintenance. :( )
Finally finished my in-depth experimentation on toroid baluns last night. Turns out that the simplest solution is often the best: a traditional transformer acting as a voltage balun did the trick!
I was a bit dismayed with the narrow bandwidth of my system with the copper pipe dipole with a 4:3 step-down ratio (it hit the center of 6m, but the SWR at the FT8 frequency wasn't as good), but but changing to 6:3 (5:3 didn't work at all) brought the resonant frequency down and got one of the best SWR readings I've seen. π
My plan is to have a switch on the balun to select between the 4:3 and 6:3.
Switching to an autotransformer got the resistive impedance really close to 50Ξ©. π
I'll need 17pF to knock out that inductive reactance, but that's cheap to do. :D
Finally made some real progress on the magloop after adding a 100 pF capacitor in parallel to the 5-250 pF variable capacitorβ¦at least on 80m. Now there's too much capacitance to hit 40m. 
The SWR on 80m is really good. When I tested FT8 at 100 W, it was around 1.1. :D
But there's a lot of noise. :(
