On Tue, 3 Oct 2006 23:27:56 -0400, "Yuri Blanarovich"
wrote:

Terman describes ducting and refraction relating to UHF

Hi Yuri,

I have a couple of refraction citations made by Ladner and Stoner in
"Short Wave Wireless Communications," 1932. They dedicate the book
to C. S. Franklin.
"Refraction may produce an appreciable increase in signal strength
at longer distances and can be expect to produce fading effects
similar to those experienced with the longer waves from the
ionosphere."

How this is achieved conforms to classic ducting, although they
neglect to call it such:
"Under certain conditions theoretical curves are available
from which the field strength at an elevated receiver,
produced from an elevated transmitter, may be deduced."

73's
Richard Clark, KB7QHC