Hi all,
I hope this is okay to post in this group as I'm new here. I've built a dipole antenna using copper tape and a RG58 coaxial for my kit aircraft as per some plans I have and I wanted to test it to see if it matched with my radio specifications of having a VSWR of under 2.5. The frequency range for the air band is 117MHz to 136MHz and I am wondering how I can flatten my SWR curve I'm seeing on the NanoVNA. As you can see from the pictures, I'm achieving an SWR of 1.57 at the midway frequency around 127MHz but at the lower frequencies it goes all the way up to 4.2 SWR.
Things that I have tried -
- I've added length to the ground strip, which makes the SWR closer to 1 in the lower frequencies but increases the SWR in the higher frequencies.
- I've taken away from the antenna strip and the SWR goes down in the higher frequencies but makes it a lot worse in the lower frequencies.
I started with a ground strip of 540mm and an antenna strip of 545mm, and now I'm at 560mm on the ground strip and 485mm on the antenna strip.
What's the best way to go about making this better? (Also, if I've made no sense, it's because I have no idea what I'm really doing...)
