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[TowerTalk] 20 Metre Yagi Designs

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Subject: [TowerTalk] 20 Metre Yagi Designs
From: donovanf@sgate.com (Frank Donovan)
Date: Sun, 23 Feb 1997 14:48:28 -0500 (EST)
David,
Here is the YO file for my 20 meter Yagis.  They are on 48 foot booms.  I
stack a pair of these at 50 and 100 feet.  I would not recommend stacking
them at 70 and 140 feet because much of the time that will be higher than
optimum for the north Atlantic path.
All dimensions are in inches.
Each column is the same diameter
Each row is a different element, starting with the reflector.
A six element beam would require a boom length of 70 feet to get any
useful additional performance relative to this antenna.  

73!
Frank
W3LPL
donovanf@sgate.com


W3LPL 5 Element 20M Yagi 48 Ft Boom
Height 2340.000
14.000 14.200 14.350 MHz
5 elements, inches
            1.2500    1.1250    1.0000    0.8750    0.7500 
  0.0000   33.7500   50.2500   33.0000   33.0000   67.0000 
 86.0000   33.7500   50.2500   33.0000   33.0000   52.0000 
171.0000   22.0000   47.8750   33.0000   33.0000   64.0000 
349.0000   22.0000   31.2500   33.0000   33.0000   77.0000 
570.0000   22.0000   43.7500   33.0000   33.0000   52.0000 

Use the M and Tab keys to enter the following 
T-match parameters: 
Rod diameter:   0.5"
Rod Spacing:      6"
Rod Length:      48"
Lead Length:      3"
Series Cap:   99999 pf
Feed Z          200 ohms

Experience indicates that the driven element
tip must be lengthened to 62 inches, the
length that produces a modelled impedance of
+j20 ohms at 14.200 MHz



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