[TowerTalk] Propagation / Beam Headings Responses

[Pete Smith]

At 11:48 AM 9/24/00 -0600, n4kg@juno.com wrote:
>
>K3KO asked an interesting question which I responded to as
>follows.   N4KG
>
>On Sun, 17 Sep 2000 alsopb <alsopb@gloryroad.net> writes:
>
>> Tom,
>> 
>> If one uses VOCAP doesn't one put in the actual sunspot number, 
>> month and day of year?  Does this not give predictions for actual
>> expected not average conditons?
>
>	The most detailed results give different percentiles,
>	such as upper 90%, upper 50%, and upper 10%
>	so the absolute peak is always higher than the 
>	published numbers.	
>
>	Other factors also come into play such as ERP
>	of both stations and antenna heights, possible E-layer 
>	enhancements / bending which allows an otherwise 
>	marginal opening to get a start.  Foreward scatter
>	can also come into play.
>
>	And finally, it is not an exact science so day to day
>	variations come into play when you are skating on
>	the edge of the MUF.

And that last one is the real deal.  In fact, unless I'm misunderstanding
severely, the IONCAP/VOACAP family of programs expect a smoothed sunspot
number, and yield a result that is highly statistical in nature -- fine for
making facility or equipment decisions, but at best a starting point for
predicting individual openings, particularly when pushing the MUF. 

73, Pete Smith N4ZR

Contesting is ... Extreme Radio

The World Contest Station Database 
is back up and running at
http://www.qsl.net/n4zr 



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