[TowerTalk] YO, AO & Hairpin

[Bill Fisher - W4AN]

Well I got a couple of responses to my inquiry on YO and hairpins.  I 
talked with W9JA on the phone and he has found YO to be very accurate.  
Only received a couple of responses however.    

I did talk to N2NC and he sent me an AO file representing my new 5 
element 20M yagi with the hairpin.  I thought it might be useful to some 
of you, so I have copied the file here.  All I had to do is set the 
driven element length (de_len) and the hairpin length (length) as 
variables in the optimizer, set SWR to 100% in options, and let AO tell 
me what combination works.  Just about as easy as YO after you get the 
hairpin drawn in the AO file.  

The AO file is below.  You may have to format it a bit due to line 
lengths.  If anyone wants the file attached, I will be happy to send it 
to you.  I also have the HyGain 204BA modelled with the hairpin drawn in 
on it too.


Start of 5EL20HP.ANT
--------------------

5 Element 20M 
Free Space Symmetric
14.150 MHz
10 6061-T6 wires, inches

; hairpin dimensions
width  =  13.5       ; hairpin width
length =  15.8365    ; hairpin length
;
hw=width/2
depos=-167.4510
hpend=depos - length 
de_len=195.6659
1   -251.4999 -209.3901    0.0000   -251.4999  209.3901    0.0000    
1.0939

; break driven element into 3 pieces (to join hairpin)
1     depos   -de_len      0.0000     depos    -hw         0.0000    
1.1057
5     depos   -hw          0.0000     depos     hw         0.0000    
1.1057
1     depos    hw          0.0000     depos     de_len     0.0000    
1.1057

; now make hairpin
; be sure to check segment density is high enough
5     depos    hw          0.0000     hpend     hw         0.0000    #10
5     depos   -hw          0.0000     hpend    -hw         0.0000    #10
3     hpend    hw          0.0000     hpend    -hw         0.0000    
#10    
; end hairpin

1   -110.8809 -195.7651    0.0000   -110.8809  195.7651    0.0000    
1.1022
1     37.8666 -191.1729    0.0000     37.8666  191.1729    0.0000    
1.1063
1    251.4999 -179.3688    0.0000    251.4999  179.3688    0.0000    
1.1161
1 source
Wire 3, center

42' boom with insulated elements.  Last designed
12/14/97.

--------
END


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