[Towertalk] OCF Longwire with moveable feed point

[Red]

Hello to all;

I also modeled a 3.5 wl wire using EZNEC and observed exactly what Pete
reports at .5 and at 1.0 wl above ground.  It is moderately directional, with
the strongest signal in an arc off either end.  The maximum signal was at
about 18 degrees above the horizon, if I remember correctly.   Impedances are
about 160 ohm at any of the 7 current nodes.  I didn't run a frequency sweep.
If it matters, I will reexamine it to measure the beamwidth and bandwidth.
Have you any info regarding height above ground and about the ground
characteristics?

73 de WOØW

Pete Smith wrote:

> At 02:23 PM 4/22/02 -0700, Terry O'Neill wrote:
>
> >The athuor of the 1969 article (John Schultz, W2EEY) plots horizontal
> >radiation patterns for a 3.5 wl version @ 9 diffrent feedpoints along the
> >length of the wire.
> >
> >The  patterns are very interesting.
>
> I just modeled a 3.5 WL wire 1/2 WL above ground, fed in the center, at
> each end, and at 25 percent of the length from one end.  The patterns are
> almost the same, regardless of the feedpoint location.  There is a wide
> bowtie pattern off the ends of the wire, with a number of minor lobes
> broadside.  Fed in the center, maximum gain is 8.26 dBi @68 degrees from
> broadside (and at the three other corresponding points).  Fed at one end,
> the pattern looks almost the same, but it is "tilted" a bit toward the end
> away from the feedpoint, with a maximum gain of 9.01 dBi at 70 degrees (and
> the three corresponding points).  The minor lobes nearest the ends are
> somewhat bigger, while those in the center are somewhat smaller than in the
> center-fed case.
>
> As someone else observed, what does change significantly is the feedpoint
> impedance.  Modeled feedpoint impedance varies from 1280-j2062 at one end
> to 159+j65 in the center.
>
> 73, Pete N4ZR
>
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