Vertical antennas, an interesting discussion

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Andrew (grayhat)
Posts: 125
Joined: Sat Jun 11, 2022 2:59 pm

Vertical antennas, an interesting discussion

Post by Andrew (grayhat) »

The infos are here

https://practicalantennas.com/designs/v ... s/5eights/

in short, a "poor" quarter wave vertical can outperform a 5/8 if installed at the "right" height, the trick is to adjust the top height :D
KL7MJ
Posts: 49
Joined: Mon May 15, 2023 9:06 pm

Re: Vertical antennas, an interesting discussion

Post by KL7MJ »

A tribander on a 100 foot tower will outperform just about anything, but it's really hard to fit one in my backpack. I think the same thing applies here - a 1/4 vertical is probably easier to carry and set up than a 5/8 vertical, so even if it may technically have better performance it loses in the "total usability" category!

73,
Mike, KL7MJ
Andrew (grayhat)
Posts: 125
Joined: Sat Jun 11, 2022 2:59 pm

Re: Vertical antennas, an interesting discussion

Post by Andrew (grayhat) »

KL7MJ wrote: Wed Nov 15, 2023 3:12 pm A tribander on a 100 foot tower will outperform just about anything, but it's really hard to fit one in my backpack. I think the same thing applies here - a 1/4 vertical is probably easier to carry and set up than a 5/8 vertical, so even if it may technically have better performance it loses in the "total usability" category!

73,
Mike, KL7MJ
You're missing the point, Mike, pick a 1/4 wave Lambda for (say) the 10m band, that will be about 2.6m long, now calculate the length for a 5/8 Lambda for the same band, you'll get about 6.5m, now let's say that the 5/8 is placed on a 1m pole, the UPPER end of the 5/8 will then be at 7.5m from ground; now, get back to the 1/4 vertical (2.6m) and install it so that the UPPER end (the TOP of the antenna) will be at 7.5m from ground, just like the top of the 5/8 antenna, and you'll have the SAME radiation angle and gain, and all this using a 5m pole to raise the 1/4 TOP END at the desired height
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