[amsat-bb] Re: satellite average elevation

Bob Bruninga bruninga at usna.edu
Tue Apr 12 05:21:52 PDT 2011

> I saw on this bb a site or note that shows the overall 
> average elevatation.  As I remember it elevation is 
> surprisingly low for most passes.  Where can I find it? 

I have a sketch on my web page: http://aprs.org/rotator1.html

It shows that 70% of the time LEO satellites are below 12 degrees.  The good news is that for the 30% of the time they are above say 12 degrees, they are 6 dB stronger.

You can visualize this anytime by recognizing that the radius of the earth is about 4000 miles.  And the radius of a LEO satellite is about 4400 miles.  So swing an arc on a sheet of paper (the earths surface), and then swing another one only 10% above it (the LEO satellite) and then draw the tangent through your station.  It is amazing to see how far away the horizon is  and how much time a satellite is way out there...


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