Here is a good article on 6m dipole.
ALL credit for this goes to Kevin Loughin. Watch his video at https://www.youtube.com/watch?v=fBdcyQvu3jM
It’s springtime here, that time of year where 6 meters occasionally opens up. And I need a decent 6-meter antenna. I’d love a beam, but I live in an RV and have very limited space. So a dipole it is.
I’ve long been aware of cage dipoles and their broader bandwidth versus a regular dipole. So I thought up a way to make a simple four-wire cage dipole for 50 MHz. Here is the design.
(Click on image for full size, then right-click on it to download.)
In order to test the increase in bandwidth, I initially just put a single wire on each leg and swept it with my Blue VNA.
(single wire dipole being measured)
And here is the sweep of the single wire dipole, showing a bandwidth of 2.6 MHz between the 2:1 points. One interesting point I noticed. Modeling and literature all point out that a half-wave resonant dipole will have ~74 ohms impedance at its resonant frequency. We measured 73.8 ohms, how about that!
Then I finished building the cage and swept it again.
(The cage version being measured.)
Here’s the result. The bandwidth has increased by 77% to 4.6 MHz!
So there we go. The cage design not only increased bandwidth but also slightly lowered the impedance and SWR at its lowest point. Some might wonder why I didn’t trim the antenna to raise the lowest SWR to the center of the band. Well, 99% of my operation on 6 meters is down at the CW/SSB/digital end of the band, so that’s where I wanted the lowest SWR.
Now I’m all ready for those coming 6-meter openings.