Please disregard message below - sent to the wrong reflector - Jerry
K4SAV wrote:
> W7RH wrote: Further with the T portion as top loading the feed point
> radiation resistance will be greater for a given vertical
> height. This when coupled with an excellent ground system of 1/4 wave
> radials will make the antenna substantially more efficient than other
> types of loading. (Less Loss)
>
> Why does NEC not confirm this statement? An example: A T antenna and
> an L, both with the same ground loss, the same vertical section length
> (49.5 ft), and the same resonant frequency. The T calculates as a
> feepoint impedance of 18.1 ohms at 1.81 MHz. The L calculates as 20.2
> ohms at 1.81 MHz. If you calculate the radiation resistance, the L
> will be 1.5 to 2 ohms higher.
>
> Note: If you do these calculations with a Mininec ground, you will get
> in incorrect answer because there will be a low horizontal wire over a
> Mininec ground. That always produces an impedance that is too low and
> a gain that is too high. You have to use a real ground and simulate
> the radials, or do the calculations in free space.
>
> Jerry, K4SAV
>
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