Topband: T-loaded vertical

[Richard (Rick) Karlquist]

On 2/19/2020 11:50 AM, Ed Sawyer wrote:

> I have personally found that for Ts that are only 70 ft vertical, like mine, the ground losses of the long topped L are not as desirable as the cancelled out horizontal lobes of the T.  If the T were say 90 ft of vertical, I don’t think the T adds as much value.

> Ed  N1UR
> 
>   

When you model an inverted L, the driving point resistance
goes up when you lengthen the top.  This it appears that
you decreased ground losses and your efficiency goes up.
However, if model vertical polarized radiation vs input
power, you find that your effective efficiency actually
goes down.

Extending the inverted L top out to where you have a 1/4
wavelength of wire seems very elegant.  The antenna
reaches resonance at 1830 and you get a low VSWR without
using a tuner.  If you model that vs a T vertical, there
is no comparison. The T wins.

Rick N6RK