[TenTec] New and Improved Terminology (NVIS origins)

[Steve Hunt]

ARRL Extra Class License Manual, Page 9-8 Effects of Ground and Ground 
Systems:

"There is little you can do to improve the far-field, low-angle 
radiation pattern of a vertically polarized antenna if the ground under 
the antenna has poor conductivity, the most important factor affecting 
ground losses. Most measures that people might try will only be applied 
close to the antenna and will only affect the near-field pattern. For 
example, you can add water to the ground under the antenna, but unless 
you watered the ground for 100 of more wavelengths, it wouldn't improve 
the ground conductivity for these distant ground reflections. Adding 
more radials or extending the radials more than a quarter wavelength 
wont help either, unless you are able to build an extensive ground 
screen under the antenna out to 10 or more wavelengths!"

http://books.google.co.uk/books?id=EcbjKvhgPLsC&pg=SA9-PA8&lpg=SA9-PA8&dq=vertical+antenna+ground+radials+reflections&source=bl&ots=0H2GN_sZFt&sig=pt4Owyr8V7zAigwm62V_0mPKQXM&hl=en&ei=xqQlTYCPMsOGhQfi_J3FAg&sa=X&oi=book_result&ct=result&resnum=4&ved=0CC0Q6AEwAw#v=onepage&q=vertical%20antenna%20ground%20radials%20reflections&f=false


Need I go on?

73,
Steve G3TXQ