[TowerTalk] Element taper in beam antennas

K7LXC@aol.com K7LXC@aol.com
Thu, 29 Jul 1999 11:19:01 EDT

In a message dated 99-07-28 19:08:58 EDT, Thomas@cybrzn.com writes:

> Am wondering to what degree element taper in a yagi affects the operating 
>  parameters of the antenna. Specifically, if I had two beams with identical 
>  element lengths and spacings but they differed slightly in diameter or in 
>  the amount of tapering, would I see any difference in resonant frequency 
>  bandwidth?

      Yes, you'd see a difference. You have to allow for taper since the 
basic calculation assumes a single dimension element. Years ago I put 
together a 4L 15M beam out of my aluminum boneyard. While the dimensions were 
what they were supposed to be, the elements had different sizes of aluminum 
because that's what I had. The danged thing was a dummy load at 115 feet. 
Lesson learned? Symmetrical element tapering is mandatory.

      Lew, K4VX, wrote a nice little taper program years ago that I used when 
I built a 6PV for 15M to replace the 15M/DL. This antenna works, tnx in part 
to Lew's program. Contact him for more details - k4vx@arrl.org.

Cheers,   Steve    K7LXC

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