TopBand: Re: NL7Z and my oversight

[Robert Brown]

Friends in Top Band Land,

In my original posting on 3/20in response to that of Jeff, K1ZM, I made 
mention of signal ducting in the electron density valley above the  
night-time E-region.  And in discussing how signals got out of the duct, I 
noted that ionospheric tilts would play a role.

Tilts are well-known but not in the literature readily available to most 
amateurs.  There is one exception, the book 

	The Ionosphere: Communications, Surveillance and Direction Finding
	by Leo F. McNamara, Krieger Publishing, 1991.

That book was the basis for a later, smaller volume by McNamara

		Radio Amaterus Guide to the Ionosphere

The discussion of ionospheric tilts is in the first book, in connection 
with direction finding.

Not only did I fail to mention that reference but also one more recent and 
relevant:
	
	How the Ionosphere REALLY Works by Eric P. Nichols, KL7AJ.
	QEX, March/April. p. 37-40, 1998.

In that article, Nichols not only gives "a catalog of aberrant behaviours" 
of the ionosphere but goes on to mention the matter of ionospheric tilts, 
the order of 35-40 degrees over certain regions.  Additional details are 
not given but his e-mail address is there:

			enichols@gci.com

so I presume he would be responsive to any inquiries.  I might add that 
his affiliation was with the HIPAS Observatory in Alaska.

Again, my apologies for the oversight.  Maybe this will help you understand 
my remarks better.

73,

Bob, NM7M

		

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