On 8/5/2014 6:54 PM, L L bahr wrote:
But how do you correctly know how to correct or adjust the reflector, or for
that matter any parasitic element? During the Dark Ages when I first got
licensed, you just made the reflector around 10% longer then the driven
element. How do you do it in 2014?
You model it, using one of several programs designed for the purpose, or
build from a published design. YW comes with the ARRL Antenna Book, and
appears to be a Windows port of a DOS program. NEC, with either W7EL's
EZNEC shell or the 4NEC2 shell. And there's K6STI's YO, a 20 year old
DOS program that's widely admired. He was selling it, it got hacked, and
he discontinued it. See the link below for a nice discussion of these
programs.
http://hamwaves.com/antennas/modelling.html
There are many Yagi designs for HF and VHF Yagis in the ARRL Antenna
Book, and in "Array of Light," N6BT's antenna book, which you can buy
from K7LXC's website. About $35, worth much more. N6BT is the original
engineer/owner of Force 12.
73, Jim K9YC
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