[Antennas] W3EDP and mobile antennas

[DJED1@aol.com]

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