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Re: HF satellite Antenna



On Fri, 9 Apr 2004, Mike Gilchrist wrote:

> At 05:13 AM 4/9/2004, Bill Sinbine wrote:
> 
> >What about trying the old "tape measure" antenna....See what a 1/2 inch 
> >wide tape would do.... I belive it has been used in the past. You wouldn't 
> >even have to guess at the length when you cut it...
> Bill:
> 
> Bob stated in an earlier post he didn't want to use the tape measure
> approach.  The small diameter of his intended radiator, at 17', is as
> much drag as the project can handle.  A fat tape would cause a faster
> decay in the orbit, and lead to an earlier death of the cubesat.

I'm wondering how the dynamic forces (aerodynamic, magnetic, gravity
gradient) acting on the satellite balance out and if they can be used to
place the antenna trailing the satellite with respect to it's velocity
vector.  In the case of the (larger) Microsats, the magnetic forces
overwhelm aerodynamic effects.

Do it right and much of the antenna will be in the wake of the satellite
body and it's contribution to total spacecraft drag will be greatly
reduced; do it wrong and Bob's worst-case assumptions come true.

73
Steve KS1G

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Stephan A. Greene     sgreene@patriot.net        ks1g@amsat.org
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