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Author Topic: Aluminum tubing v. rod for yagi elements  (Read 4518 times)
KD5GR
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Posts: 104




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« on: October 04, 2012, 03:35:55 PM »

I'm gathering information to build a 2 meter/70cm 5 element yagi.  The difference in raw material cost for 6061 aluminum tubing v. rod of the same size is amazing.  For example 3/8" tubing is about $17 for a 48" joint v. $2.70 for 3/8 rod of the same length.  There's obviously a weight difference, but the finished product will only be about 7 pounds including the 1" boom.

Is there any reason not to use the aluminum rod instead of tubing?  Also, is there a bandwidth benefit to using 1/2" v. 3/8" elements?

Thanks guys,
Chas.
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MDNITERDER
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Posts: 146




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« Reply #1 on: October 04, 2012, 04:06:11 PM »

 I know tubing is far more rigid than solid bar. Well maybe not far more rigid but the radials will be less prone to sag vs solid.
« Last Edit: October 04, 2012, 04:08:58 PM by MDNITERDER » Logged
WB6BYU
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Posts: 13487




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« Reply #2 on: October 04, 2012, 04:10:00 PM »

Use whatever is cheaper. 

(Technically one could make a slight correction to element lengths because the
end of the tubing isn't flat, but it isn't enough to worry about.)

There is a slight bandwidth improvement with 1/2" material, and it will shift the
element tuning somewhat. If you want an optimized antenna you would readjust
the element lengths for the change in element diameter, but for a general-purpose
antenna it probably doesn't make a significant difference.
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