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DISH SETUP: Single sat, Multi-Sat & Motorised
finding the arc
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<blockquote data-quote="2old4this" data-source="post: 6087" data-attributes="member: 174998"><p>Yes you are talking rubbish ;-)</p><p></p><p>I also suspect you haven't yet read the info at the links I posted earlier... please do, since it gives a step-by-step account of how to set up a motorized dish.</p><p>There's also a detailed account in the annual 1999 review of What Satellite that you may be able still to get in the UK shops.</p><p></p><p>Normally there are instructions provided with a motor, on how to align the dish. Did you not get any instructions with your Jaeger?</p><p></p><p>In any event, there are several ways of doing it. Here's my method:</p><p></p><p>(1) set elevation & declination of the dish as accurately as possible.</p><p>See here: http://www.geocities.com/~saltillocib/sizepgs/tuningp4.html#anchor797917</p><p></p><p>(2) align dish to point due South (use a compass and make a correction for magnetic deviation. The more accurate the better. Next to a non-vertical pole, failure to align on geographic due south is the single biggest cause of failure to track accurately across the full arc.</p><p></p><p>(3) secure the dish/motor on the mounting pole at that point.</p><p></p><p>(4) use the motor to then find the satellite which is nearest the highest point of the arc. The highest point of the arc depends on your geographical location (I live at longitude 5 degrees east approximately, and so for me the highest point of the arc is at 5 east. This corresponds almost exactly with Sirius, so I use Sirius as my target. But if you are in the UK, Thor may be closer to the high point.) </p><p></p><p>(5) you will probably need to re-adjust the elevation/declination of the dish now to find the satellite. Use that SMW program to calculate the elevation of the target satellite from your location. Elevation of the dish should be that minus the declination value which corresponds to your latitude. I gave the link to the SMW program in a previous post in this thread. </p><p></p><p>NB: you may have to iterate the last two steps to find the target satellite, but do not (yet) re-adjust for the South alignment of the whole assembly. </p><p></p><p>(6) with the terget sat located, it is now a question of moving progressively further down both sides of the arc, locating other satellites. If you are very lucky, you will have everything. More likely, you will get the first few, then you will get nothing more. This would indicate that the arc your dish is tracking is not exactly aligned with the Clarke belt (arc of satellites).</p><p>The most usual cause is that the South alignment is out. </p><p>One easy technique is as follows:</p><p>When you just fail to find the next satellite at the expected position, use gentle pressure on the dish to deflect it up and down. If when bending up the sat comes into view, it means your dish is too low at that point. And assuming for the moment that the curvature of the dish's arc was ok, this would mean that the whole arc was displaced to the right (ie, as seen from the northern hemisphere: to far to the west) of the position it should be tracing. Then you need to loosen the motor clamp, and swing the whole assembly a fraction to the left (ie to the east). Just a fraction! A millimeter or two! Vice-versa if the sat was found by deflecting the dish downwards. What you are actually doing here is refining your alignment on true geographic south.</p><p></p><p>(7) of course, the curvature of the dish's arc might have been too sharp or too wide. So the adjustment left/right of the mounting may still not actually bring in the whole arc. The actual curvature of the arc traced by the dish is dependent on the elevation/declination of the dish. So you could tweak those too. But only do that after the south-alignment has failed to provide any more improvement (ie only when you have got as much of the arc as possible using the left/right motor+dish realigment).</p><p></p><p>Phew, that's it.</p><p>It will take several hours unless you have a good signal meter or are able to pick up analogue signals on each sat.</p><p></p><p>2old</p></blockquote><p></p>
[QUOTE="2old4this, post: 6087, member: 174998"] Yes you are talking rubbish ;-) I also suspect you haven't yet read the info at the links I posted earlier... please do, since it gives a step-by-step account of how to set up a motorized dish. There's also a detailed account in the annual 1999 review of What Satellite that you may be able still to get in the UK shops. Normally there are instructions provided with a motor, on how to align the dish. Did you not get any instructions with your Jaeger? In any event, there are several ways of doing it. Here's my method: (1) set elevation & declination of the dish as accurately as possible. See here: http://www.geocities.com/~saltillocib/sizepgs/tuningp4.html#anchor797917 (2) align dish to point due South (use a compass and make a correction for magnetic deviation. The more accurate the better. Next to a non-vertical pole, failure to align on geographic due south is the single biggest cause of failure to track accurately across the full arc. (3) secure the dish/motor on the mounting pole at that point. (4) use the motor to then find the satellite which is nearest the highest point of the arc. The highest point of the arc depends on your geographical location (I live at longitude 5 degrees east approximately, and so for me the highest point of the arc is at 5 east. This corresponds almost exactly with Sirius, so I use Sirius as my target. But if you are in the UK, Thor may be closer to the high point.) (5) you will probably need to re-adjust the elevation/declination of the dish now to find the satellite. Use that SMW program to calculate the elevation of the target satellite from your location. Elevation of the dish should be that minus the declination value which corresponds to your latitude. I gave the link to the SMW program in a previous post in this thread. NB: you may have to iterate the last two steps to find the target satellite, but do not (yet) re-adjust for the South alignment of the whole assembly. (6) with the terget sat located, it is now a question of moving progressively further down both sides of the arc, locating other satellites. If you are very lucky, you will have everything. More likely, you will get the first few, then you will get nothing more. This would indicate that the arc your dish is tracking is not exactly aligned with the Clarke belt (arc of satellites). The most usual cause is that the South alignment is out. One easy technique is as follows: When you just fail to find the next satellite at the expected position, use gentle pressure on the dish to deflect it up and down. If when bending up the sat comes into view, it means your dish is too low at that point. And assuming for the moment that the curvature of the dish's arc was ok, this would mean that the whole arc was displaced to the right (ie, as seen from the northern hemisphere: to far to the west) of the position it should be tracing. Then you need to loosen the motor clamp, and swing the whole assembly a fraction to the left (ie to the east). Just a fraction! A millimeter or two! Vice-versa if the sat was found by deflecting the dish downwards. What you are actually doing here is refining your alignment on true geographic south. (7) of course, the curvature of the dish's arc might have been too sharp or too wide. So the adjustment left/right of the mounting may still not actually bring in the whole arc. The actual curvature of the arc traced by the dish is dependent on the elevation/declination of the dish. So you could tweak those too. But only do that after the south-alignment has failed to provide any more improvement (ie only when you have got as much of the arc as possible using the left/right motor+dish realigment). Phew, that's it. It will take several hours unless you have a good signal meter or are able to pick up analogue signals on each sat. 2old [/QUOTE]
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DISH SETUP: Single sat, Multi-Sat & Motorised
finding the arc
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