#### 19dsniper

##### Member

Today i built my first antenna. A simple 1/4 wave ground plane with copper wire and a SO239 connecter. What i found very interesting was when i was complete and i started to check power and swr, that i was able to tune the SWR and in turn, adjust power out, while changing the angle of the radial elements.

I first started with them almost fully horizontal. I first tried at 5 watts just to check everything out. I was only able to get 4 watts out and an SWR of 3.0:1. After adjusting them closer to 45 degrees down, I was able to bring the power up to 5 watts with an SWR of 1.5:1, so i kept going. Adjusting them to almost 90 degrees i was able to get a full 5 watts with so little noticeable bump on the SWR meter the it was lower than 1.1:1.

I found this very interesting and tried it on 2 other frequencies that were a ways apart, and again it started at lower power with a high swr, and after adjusting, i was able to TX full rated power with a SWR of 1.1 or less.

All of this was done without any trimming of the radials, which i expected that i would need to do.

Can someone explain how i was able to basically "tune" this antenna by adjusting the radial elements instead of adjusting the length?

Also, im guessing that by adjusting my radial elements lower than 45 degrees that im actually effecting the radiating pattern. So am i better to actually trim the elements with them at 45 degrees to adjust swr and power, so that my radiation pattern is ideal, or adjust the angle to have 1 antenna that can be tuned to be resonant on different frequencies based off of the angel of the radiating elements?

Im wanting to get into antenna theory, so yes im very new to this, but someone please educate me.

I first started with them almost fully horizontal. I first tried at 5 watts just to check everything out. I was only able to get 4 watts out and an SWR of 3.0:1. After adjusting them closer to 45 degrees down, I was able to bring the power up to 5 watts with an SWR of 1.5:1, so i kept going. Adjusting them to almost 90 degrees i was able to get a full 5 watts with so little noticeable bump on the SWR meter the it was lower than 1.1:1.

I found this very interesting and tried it on 2 other frequencies that were a ways apart, and again it started at lower power with a high swr, and after adjusting, i was able to TX full rated power with a SWR of 1.1 or less.

All of this was done without any trimming of the radials, which i expected that i would need to do.

Can someone explain how i was able to basically "tune" this antenna by adjusting the radial elements instead of adjusting the length?

Also, im guessing that by adjusting my radial elements lower than 45 degrees that im actually effecting the radiating pattern. So am i better to actually trim the elements with them at 45 degrees to adjust swr and power, so that my radiation pattern is ideal, or adjust the angle to have 1 antenna that can be tuned to be resonant on different frequencies based off of the angel of the radiating elements?

Im wanting to get into antenna theory, so yes im very new to this, but someone please educate me.

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