Re: USA 144: The Mystery Deepens - Flash Timings Needed

From: Sven Grahn (svengrahn@telia.com)
Date: Tue Aug 06 2002 - 15:41:20 EDT

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    At 14:32 2002-08-06 -0500, Allen Thomson wrote:
    
    >A couple of random thoughts on this thread:
    >
    >Antennas: Very large antennas will mostly be made of metal or
    >metallized mesh, with the holes being somewhat smaller in linear
    >dimension than the smallest wavelength the antenna is intended
    >to work with. That's still likely to be much larger than the
    >wavelength of visible light, and much larger than the typical
    >air molecule.  The upshot of this is that visual brightness (on
    >a linear scale, W/m^2 or the like), drag and SRP are likely all
    >to be proportional to the physical area of the threads of the
    >mesh, not the overall dimensions of the antenna. And, therefore,
    >proportional to each other.
    >
    >Solar panels: Just the obvious comment that some observations
    >should be made at small phase angles, where brightening and/or
    >glints might be anticipated from surfaces normal to the incident
    >sunlight.
    >
    >
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    Normally the holes should be 1/16 th of a wavelength to provide a 
    "leak-proof" RF surface.
    
    Sven Grahn
    
    
    
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