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DISH SETUP: Single sat, Multi-Sat & Motorised
Eutelsat 10/9 reception - or not
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<blockquote data-quote="a33" data-source="post: 1114524" data-attributes="member: 332642"><p>Well, that is a very very rough estimate. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite53" alt=":confused" title="Confused :confused" loading="lazy" data-shortname=":confused" /></p><p>Remember that when the ground has its fist shadow, the sun still lights the clouds above for some time (seemingly from beneath), as they are not in the earth's shadow yet.</p><p>This is even much longer for the satellites, that are still further away.</p><p></p><p>I now calculated more exact: </p><p>=DEGREES(ARCSIN(6378/42164)) gives 8.7 degrees, is half the earth's shadow angle for the clarke belt at the equator.</p><p>So in total it is 17.4 degrees.</p><p>In 24 hours, the satellite rotates 360 degrees.</p><p><strong>The 17.4 degrees takes 1 hour and 9,6 minutes.</strong></p><p>( I guess several minor factors are not taken into account here.)</p><p></p><p>But this is only for the shadow pass of the Clarke Belt, when that shadow is exactly in line with sun and earth equator; so in spring and autumn (equinox-time).</p><p>As the earth axis is tilted 23.5 degrees, the seasonal effect that I mentioned is even greater than I thought.</p><p></p><p>Because of the axis tilt, at the longest day in summer, <strong>at 'shadow time'</strong> the satellite is =42164*SIN(RADIANS(23.5)) = 16813 km <strong>above the line sun-earth</strong>, so by no means in the shadow of the earth (with <em>polar</em> radius 6357 km). </p><p>As we are now near that date, I guess the satellites are sun-lit 24/7 at the moment.</p><p></p><p></p><p>Where your reception fluctuations come from? I don't know. I'll leave that question to others, here.</p><p></p><p>Greetz,</p><p>A33</p></blockquote><p></p>
[QUOTE="a33, post: 1114524, member: 332642"] Well, that is a very very rough estimate. :confused Remember that when the ground has its fist shadow, the sun still lights the clouds above for some time (seemingly from beneath), as they are not in the earth's shadow yet. This is even much longer for the satellites, that are still further away. I now calculated more exact: =DEGREES(ARCSIN(6378/42164)) gives 8.7 degrees, is half the earth's shadow angle for the clarke belt at the equator. So in total it is 17.4 degrees. In 24 hours, the satellite rotates 360 degrees. [B]The 17.4 degrees takes 1 hour and 9,6 minutes.[/B] ( I guess several minor factors are not taken into account here.) But this is only for the shadow pass of the Clarke Belt, when that shadow is exactly in line with sun and earth equator; so in spring and autumn (equinox-time). As the earth axis is tilted 23.5 degrees, the seasonal effect that I mentioned is even greater than I thought. Because of the axis tilt, at the longest day in summer, [B]at 'shadow time'[/B] the satellite is =42164*SIN(RADIANS(23.5)) = 16813 km [B]above the line sun-earth[/B], so by no means in the shadow of the earth (with [I]polar[/I] radius 6357 km). As we are now near that date, I guess the satellites are sun-lit 24/7 at the moment. Where your reception fluctuations come from? I don't know. I'll leave that question to others, here. Greetz, A33 [/QUOTE]
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DISH SETUP: Single sat, Multi-Sat & Motorised
Eutelsat 10/9 reception - or not
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