[Antennas] W3EDP and mobile antennas

2002年5月19日 17:43:43 -0700

I have read something like this. But this has been put a little better.
But this brings to mid another question. An inverted "L" is suggested for 
160m. When would the horizontal become a cap hat or when would the cap hat 
become the horizontal part of the inverted "L". I have readc some of 
Cebik's articles on cap hats. Very interesting, spirals (one and two 
elements. ) 'radials' ends connected with circle or not. Many forms, but 
when would it be called a cap hat or a horizontal part, when only one?
Chris opr VE7HCB
At 07:37 PM 2002年05月19日 -0400, you wrote:
>The radiation resistance will increase as the square of the height for
>radiators much smaller than a quarter wavelength. So 16 feet gives you 4
>ohms, and 32 feet gives you about 16 ohms. A capacitive top hat will
>increase the effective height by 50 to almost 100 %, depending on how big the
>top hat is. The biggest top hat I know is the Cutler Maine VLF antenna. It
>uses something like 8 -1000ft towers to create a top hat acres in size. They
>get to almost 50% efficiency at 30 KHz ( and 1 megawatt ERP).
>Ed