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RE: HELP!!!! - Major Frustration



>>> "Robert McGwier" <rwmcgwier@comcast.net> 7/7/04 12:33:11 AM >>>
>... And to use a ground plane vertical means that 
>though you will be 90% efficient on the vertical (elevated 
>radials and little ground loss), you have a big null up, 
>when the satellite is at closest approach.

But that occurs only 2% of the total access times.  In fact,
a LEO satellite is above 50 degrees less than 4% of the
time.  But it is 10 dB closer, so a vertical will have good
performance somewhere between 96 to 98% of the time...

Similarly the satelite is below 30 degrees 84% of the time.
See the table on:

http://www.ew.usna.edu/~bruninga/rotator1.html

But COAX loss is the biggest killer.  That's why operating
satellite mobile works so well.  Short coax.  But the
problem (see above) is that it is rare back east for your
mobile to see down below 20 degrees where the satellite
spends most of its times...

Bob

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