[Antennas] W3EDP and mobile antennas
[email protected]
[email protected]
2002年5月19日 19:37:27 EDT
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