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Satellite Systems - What to Buy - What to install
I'm so lost.. Dish size, lnb type, location & signal: Madeira
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<blockquote data-quote="archive10" data-source="post: 1011705"><p>Without being an expert on wave-front propagation in radio frequency antenna apparatus, I would dare speculate that the answer lies in the ratio between the wave-length and dish size. The smaller the dish, the larger a dispersion (or "un-focusedness") wrsp to a specific wavelength, say, 11 GHz.</p><p></p><p>When you move to C-band (~4 GHz), you seem to get away with a much more relaxed positioning of LNBs.</p><p>In Ka-band (22 GHz), the mounting position of the LNB is ultra-critical to reception. LNB fixtures for Ka-band dishes seems much more rigorous than the Ku cousins.</p><p></p><p>I think (and I am still speculating), that the larger the dish, the faster the signal quality (and probably also strength) drops as you move away from the centre-position.</p><p>Therefore, the conjecture would be that multi-LNB arrangements on large, say, 3m dishes does not scale up directly from multi-LNB on, say, a 60 cm dish.</p><p>Unless you also scale up the wavelength... (which is harder)</p><p></p><p>I repeat: This is all speculation and conjecture on my behalf - I am happy to be proven wrong (or right!)</p><p>(But discussion like that is what makes this forum worthwhile!)</p><p></p><p>My guess is that as you move beyond 1.2-1.5 metres, the effectiveness of a multi-LNB arrangement starts to fade.</p><p>Instead, you would want to build a toroidal dish to cater for multi-LNB reception.</p><p>To the best of my knowledge, the largest mass-manufactured consumer toroidal was the SMW OA-1600.</p><p>The currently largest is the Wave Frontier T-90.</p><p>Then there are the built-to-order very-large ones primarily from GD SatCom, but that's generally for the budget of government intelligence agencies and large corporations such as Microsoft.</p><p></p><p>So for multi-sat operation, such as what OP wanted, I still believe the best bet is to have a T90, or even two T90s (like our Norwegian Friend here <a href="https://www.satellites.co.uk/forums/threads/dual-t90-setup.148914/" target="_blank">Dual T90 setup</a> ), and point them at the stronger/relevant sats in the sky. This would give thousands upon thousands of tv channels instantly switchable - more than a decent sized hotel audience could be satisfied with in a normal evening's watching.</p><p></p><p>But I think that OP has determined that a 1.8m motorised Laminas will do the job, and has now gone off to pursue some other challenge, like multi-level pool excavation planning, with due vigour and a get-results-fast-approach, so my solution becomes academic at this point... <img src="https://www.satellites.co.uk/styles/default/xenforo/smilies/smile.png" class="smilie" loading="lazy" alt=":)" title="Smile :)" data-shortname=":)" /></p></blockquote><p></p>
[QUOTE="archive10, post: 1011705"] Without being an expert on wave-front propagation in radio frequency antenna apparatus, I would dare speculate that the answer lies in the ratio between the wave-length and dish size. The smaller the dish, the larger a dispersion (or "un-focusedness") wrsp to a specific wavelength, say, 11 GHz. When you move to C-band (~4 GHz), you seem to get away with a much more relaxed positioning of LNBs. In Ka-band (22 GHz), the mounting position of the LNB is ultra-critical to reception. LNB fixtures for Ka-band dishes seems much more rigorous than the Ku cousins. I think (and I am still speculating), that the larger the dish, the faster the signal quality (and probably also strength) drops as you move away from the centre-position. Therefore, the conjecture would be that multi-LNB arrangements on large, say, 3m dishes does not scale up directly from multi-LNB on, say, a 60 cm dish. Unless you also scale up the wavelength... (which is harder) I repeat: This is all speculation and conjecture on my behalf - I am happy to be proven wrong (or right!) (But discussion like that is what makes this forum worthwhile!) My guess is that as you move beyond 1.2-1.5 metres, the effectiveness of a multi-LNB arrangement starts to fade. Instead, you would want to build a toroidal dish to cater for multi-LNB reception. To the best of my knowledge, the largest mass-manufactured consumer toroidal was the SMW OA-1600. The currently largest is the Wave Frontier T-90. Then there are the built-to-order very-large ones primarily from GD SatCom, but that's generally for the budget of government intelligence agencies and large corporations such as Microsoft. So for multi-sat operation, such as what OP wanted, I still believe the best bet is to have a T90, or even two T90s (like our Norwegian Friend here [URL="https://www.satellites.co.uk/forums/threads/dual-t90-setup.148914/"]Dual T90 setup[/URL] ), and point them at the stronger/relevant sats in the sky. This would give thousands upon thousands of tv channels instantly switchable - more than a decent sized hotel audience could be satisfied with in a normal evening's watching. But I think that OP has determined that a 1.8m motorised Laminas will do the job, and has now gone off to pursue some other challenge, like multi-level pool excavation planning, with due vigour and a get-results-fast-approach, so my solution becomes academic at this point... :) [/QUOTE]
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Satellite Systems - What to Buy - What to install
I'm so lost.. Dish size, lnb type, location & signal: Madeira
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