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
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|