TopBand: Re: Why the duct?

[w8jitom@postoffice.worldnet.att.net]

Hi Yuri,

> From:          K3BU@aol.com
> Date:          Mon, 7 Jul 97 22:54:42 +0000

> Because it is a uniform surface of water, helping to maintain uniform layer
> of duct. In a uniform or smoothly curved duct, we get smooth refraction of
> signal which gets "trapped" in the duct and is enhanced. When you get over
> land, irregular terain with updrafts of warmer air "break up" the layer
> (different dielectric constant), make them "bumpy" and inefficient to
> propagate the signals in the duct.

Are you sure the ionosphere is affected by updrafts from the 
condition or type of earth below it? Do these vertical updrafts cut 
through the trade winds and jet streams, dominating their effects, 
and simply never exist over water? Is the ionosphere affected by 
lower atmosphere winds? 

> The other possibility is what Tesla speculated, that the ocean (earth) is a
> one plate of capacitor (maybe electrode in a space "vacuum" tube), ionosphere
> is the other one, and signal gets propagated, maybe even amplified between
> them.

Tesla speculated on lots of things, back when 20 kHz was the upper 
limit of useful frequencies. I have no doubt at all that on Tesla's 
operating frequencys there was a duct between the earth and the 
ionosphere, but that duct is far different than the proposed duct of 
a 160 meter signal between poorly conductive and very lossy (lossy at 
low incident angles) layers of the ionosphere. 

Tesla was wrong about the ionosphere having a negative resistance, 
and power gain.

73, Tom W8JI 

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