At 09:10 PM 7/9/03 -0500, Mike Urich wrote:
>I'm going to try to build a new 6 meter yagi for the contest next week end.
>I'm only going with two elements for space considerations. I'm also
>considering a driven / director configuration as opposed to reflector /
>driven in as much as I'm not concerned about F/B ratios and being able to
>hear off the back side may be advantages.
>
>I went and looked at some different designs and have seen spacing from as
>little as .17 wave to .30 wave. I'm leaning towards somewhere around .22 -
>.25 wave. So I'm polling y'all to see what you have to say.
Most 2L director yagis have spacing much closer that you describe. You'll
find there is a lot more gain in the 0.1 wavelength region. As you say,
you're not looking for F/B, and at 50 MHz bandwidth is not a major
consideration. The shorter boom is also an advantage mechanically - it's
only roughly 24 inches at 50 MHz!
OTOH, reflector yagis are typically in the .15-.20 wavelength range. On
HF, most of these are seen as 2L loaded 40M beams, or some of the Force 12
tribander variants. F/B and bandwidth are concerns in these applications.
K8CC
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