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Re: Magnifier vs Classical TC
---------- Forwarded message ----------
Date: Thu, 16 Oct 1997 19:05:53 -0700
From: randy-at-gte-dot-net
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Magnifier vs Classical TC
Tesla List wrote:
>
> ---------- Forwarded message ----------
> Date: Wed, 15 Oct 1997 20:51:09 -0500
> From: "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Magnifier vs Classical TC (fwd)
>
> <SNIP>
>
>
> Hertzian waves emitted from the surface of this planet, regardless of
> launch angle, cannot penetrate and escape the ionosphere into space
> (as a generalization) much below 20 MHz. <snip>
I believe I am correct in my recollection of the following:
The ionosphere can either absorb, reflect, or _refract_ signals.
The reason you can hear AM/BC/MW sigs at night that would not have made
it to you is that the D-layer of the ionosphere (Heavyside Layer for
the old-timers) absorbs it, but the D-layer is sucked into the E-layer
when the Sun isnt pumping into it. The E-layer can either reflect
(you can receive the distant station) or refract (the sig is bent, but
at too-small an angle to return to Earth). I think there is something
called the "pseudo-Brewster angle" that defines this phenomena. I think
this is the same effect that makes a striaght pole stuck in water appear
to be bent at the water line.
You are correct that the solar flux etc would affect the frequency at
which sigs are reflected or refracted. A 3MHz sig can easily bounce back
straight down; a 30 MHz sig will generally not come down anywhere near
the point of origin, and may or may not come down at all. In other words,
I think the 30- MHz sig "escaped" via refraction. "Sporadic-E" skip
is a joker in the equation tho, the bounced sig can come down almost
anywhere within reason. My point is: sigs way below 20 MHz can 'escape"
to the depths of space, depending on Solar Flux etc.
Randy