At 06:55 AM 2008-11-28, Pete Smith N4ZR wrote:
>I am modeling a 20M 2-element delta loop array with the apex up, 12-foot
>spacing and the bottom about 35 feet above ground, fed at a lower corner,
>using Multi-NEC and NEC2. In driven/reflector configuration, it looks
>about like what I'd expect - 6 dBi gain and 14-18 dB F/B. But in the
>driven/director configuration, there isn't much directivity at all,
>regardless of frequency.
>
>Does this square with others' experience, or am I messing something up in
>the model?
I tried this in EZNEC and get the same sort of results. With a ~5%
smaller director, the F/B is about 3 dB with 12 foot
spacing. Decreasing the director spacing improves the F/B very
slightly: with 7 foot (0.1 wl) spacing, it's about 5 dB.
73, Terry N6RY
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