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Re: radio propagation



Go to Feynman, Vol II, 7-3 "Plasma oscillations".
The discussion is short and not mathematically taxing - I'll tease you with part of the concluding remarks:
 
"[So]if one tries to propagate a radiowave through the ionosphere ... it can penetrate only if its frequency is higher than the plasma frequency.  Otherwise the signal is reflected back . . ."
 
Bob Sciamanda
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
Sent: Monday, April 16, 2001 11:31 PM
Subject: radio propagation

I was looking through some of my father's ham radio books
recently, and came across something I didn't understand.
They describe how radio signals (we're talking
about 20-40 meters typically) propagate over long
distances by multiple reflections from the ground
and the ionosphere.