TopBand: Re: Why the duct?

[K3BU@aol.com]

I was trying to come up with some spare time to continue expanding and
exploring on my original "ducting" article in June 1980 CQ Magazine, but
(un)fortunately got busy with other more pressing stuff. In the mean time few
more cents worth of my opinion:

In a message dated 97-07-08 20:59:05 EDT, W8JI writes:

<<  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?  >>

I believe that on the way of signal to and from our antennas (and
ionosphere), it goes through the atmospheric layers (various compositions,
temperatures, etc.) with varying dielectric constant, which would change the
angle of refraction. As we definitely know from VHF we can duct at quite low
heights. Another example of propagating (ducting?) is the greyline, which is
basically more-less uniform circle of conditions created by the transition
from sunlite to moondark. So signal might be above us, but "messed up"
atmosphere might not allow enough of signal through to our particular QTH to
be detected. Sure looks like that signal is "floating" up there, and it might
be just atmospheric condition that will let it through to a particular spot
on earth.

I recommend looking up my article, if hard to get, I will try to put it up on
my home page. I just wish I had more spare time to spend on this subject and
more experiments, perhaps soon. 

On Tesla: 
Sure he did not know what we know now, but he new a lot more and saw far more
ahead, than most of us do. I would not discard the idea of "space" capacitor
or a vacuum tube to have something to do with propagation. 

In the mean time I am looking for any unusual (good) spots for contest
station (like salt water lake on the top of the hill, overlooking ocean) on
the coast from ME to DE, will travel to check it out with my radiomobile.
Anyone with tips or experiences, please let me know. 

73  Yuri, K3BU, VE3BMV


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