Topband: Air wound coil

[Joe Subich, W4TV]

> Getting to six would result in a smaller top hat but may not be worth
> the mechanical hassle.
If the mast has traditional three way guying, the mechanical hassle for
a six wire top hat may not be that much greater than a four wire top
hat.

If the top hat wires slope downward, keeping them to the minimum length
will result in maximum efficiency (and minimum "shielding" of the top
of the vertical element).

73,

    ... Joe, W4TV


On 2018-09-03 7:20 AM, Paul Christensen wrote:
> I ran the same model in 4Nec2 as below but changed the hat from the traditional two wires to four, spaced 90 degs.  Complex base Z is near 16+j0.  Even though two symmetrical top-hat wires produce little radiation, four wires result in wires that are only 24 ft long to achieve resonance -- versus 41 ft with only two wires.  Getting to six would result in a smaller top hat but may not be worth the mechanical hassle.
> 
>> "4Nec2 shows that with a 68 ft. thin radiator, resonance can be achieved with wires roughly 41 ft. per side.  With a ground field of 60 radials, 90 ft long on sandy ground, 4Nec2 reports a base impedance of 15.4+j2.5."
> 
> Paul, W9AC
>