[time-nuts] Quadrifilar Helix Antenna

David Kirkby david.kirkby at onetel.net
Sun Jun 10 01:50:14 UTC 2012


On 10 June 2012 01:39, Jim Lux <jimlux at earthlink.net> wrote:

> NEC can do a pretty good job on a helix, and it's free. I like 4nec2 as a
> front end.

I've never tried NEC on them. I quite like MMANA-GAL myself. But it
only supports NEC2.

> NEC will also do a patch: Model it as a grid of wires using the guideline of
> "surface area of wire is spacing between wires".. that is, if you have wires
> on a 1cm grid, then the wire diameter should be 1/pi cm.  Even if you thin
> the wires out (so you can get them closer to the ground plane), it still
> works pretty well.

I found a paper about that rule with NEC, and it basically showed it
was not a good of thumb. I just can't think where it is (what
computer, what directory).


Dave



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