[TowerTalk] Element taper in beam antennas
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
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 - firstname.lastname@example.org.
Cheers, Steve K7LXC
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