[time-nuts] Quadrifilar Helix Antenna

Jim Lux jimlux at earthlink.net
Sun Jun 10 14:00:57 UTC 2012


On 6/9/12 6:50 PM, David Kirkby wrote:
> 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.

4nec2 does both NEC2 and NEC4

>
>> 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).
>
funny.. the rule of thumb comes from Jerry Burke (one of the NEC authors)



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