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Fringe Reception General
Badr 4,6. 26 E
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<blockquote data-quote="dovercat" data-source="post: 651189" data-attributes="member: 274033"><p>[ATTACH]25702[/ATTACH]</p><p></p><p>A photo of my current Moteck sg2100a with my old Jaeger SMR-99G H-H below for comparison, The Moteck weighs at least 1kg less. Rember the Jaeger is rated only up to 1.1mtr while Moteck claim suitability for 1.2mtr dishes and my dish is only 1mtr (about 69% of the surface area of a 1.2mtr). 36V motorised mounts designed to take 1.2mtr dishes are in the region of 4x or more heavier than than the Moteck sg2100a.</p><p></p><p>I have also discovered that a DiSEqC motor increases the noise in the signal - receiver signal quality ratting, in my case having about twice the effect as the difference between the best and worst LNBs I own.</p><p></p><p>I have read up on satellite dish specs. The Triax dish spec using 11.7GHz instead of 11GHz like Televes does not guarantee that it will be quoting a higher gain figure than if it used 11GHz, as the higher the frequency the more small deviations in the dish will reduce gain. So using a higher frequency to measure dish gain is a sign of quality not a way of boosting the gain figure. </p><p>Converting the spec gain figures to a avearage 65% efficiency offset dish you get. Televes (102x113cm) 1mtr is equivelent to a 1.14mtr dish with 65% efficiency. Triax TD110 (102x110cm) is equivelent to a 1.04mtr dish with 65% efficiency. The televes is slightly physically larger and measures gain at a lower frequency so gain is less effected by surface imperfections. </p><p></p><p>I have also read the specs for the Inverto Black Ultra 0.2dB LNB. I see it is actually NF 0.7dB max (50.72K), which is very marginally worse than my Televes 0.5dB (35.39K). (to compare LNB NF you need to use the max figures, convert them to degrees K then add dish noise temperature of around 30-100K in clear skys more with heavy cloud cover or rain, so the comparison ends up being 80.72-150.72+ vs 65.39-135.39+) Oddly the Inverto appears to be coloured black which is the worst colour for an LNB since you want it to keep cool by reflecting heat not get warm by absorbing it, the Televes LNB is white which is the correct colour for a LNB. So the Inverto might have slightly lower sensitivity to weak signals.</p><p>The Inverto also has slightly worse polarity discrimination -23dB Inverto vs -25db Televes so maybe slightly less sensitive on signals with powerful opposite polarity signals.</p><p>The Inverto local oscillator stability maybe slightly worse than my Televes, initial +/-1MHz, temperature drift +/-3MHz, working temperature -30 to +60 degrees C Inverto vs +/-2MHz, working temperature -30 to +60 degrees C Televes so maybe slightly more bit-rate errors particularly on narrow - low bitrate signals. </p><p>But the most important spec is phase noise and on this crucial spec the Inverto has a much better lower phase noise -90dB Inverto vs -75dB Televes, low phase noise is crucial for good digital reception of weak signals as it is noise being added to the digital signal and on this spec the Inverto clearly beats the Televes.</p><p>I will pick one up in the new year and see if it performs better than the Televes due to the lower phase noise. Professional LNBs have local oscillator stability measured in the kHz not the MHz and measure phase noise at 1kHz not 10kHz, so they maybe better.</p></blockquote><p></p>
[QUOTE="dovercat, post: 651189, member: 274033"] [ATTACH]25702[/ATTACH] A photo of my current Moteck sg2100a with my old Jaeger SMR-99G H-H below for comparison, The Moteck weighs at least 1kg less. Rember the Jaeger is rated only up to 1.1mtr while Moteck claim suitability for 1.2mtr dishes and my dish is only 1mtr (about 69% of the surface area of a 1.2mtr). 36V motorised mounts designed to take 1.2mtr dishes are in the region of 4x or more heavier than than the Moteck sg2100a. I have also discovered that a DiSEqC motor increases the noise in the signal - receiver signal quality ratting, in my case having about twice the effect as the difference between the best and worst LNBs I own. I have read up on satellite dish specs. The Triax dish spec using 11.7GHz instead of 11GHz like Televes does not guarantee that it will be quoting a higher gain figure than if it used 11GHz, as the higher the frequency the more small deviations in the dish will reduce gain. So using a higher frequency to measure dish gain is a sign of quality not a way of boosting the gain figure. Converting the spec gain figures to a avearage 65% efficiency offset dish you get. Televes (102x113cm) 1mtr is equivelent to a 1.14mtr dish with 65% efficiency. Triax TD110 (102x110cm) is equivelent to a 1.04mtr dish with 65% efficiency. The televes is slightly physically larger and measures gain at a lower frequency so gain is less effected by surface imperfections. I have also read the specs for the Inverto Black Ultra 0.2dB LNB. I see it is actually NF 0.7dB max (50.72K), which is very marginally worse than my Televes 0.5dB (35.39K). (to compare LNB NF you need to use the max figures, convert them to degrees K then add dish noise temperature of around 30-100K in clear skys more with heavy cloud cover or rain, so the comparison ends up being 80.72-150.72+ vs 65.39-135.39+) Oddly the Inverto appears to be coloured black which is the worst colour for an LNB since you want it to keep cool by reflecting heat not get warm by absorbing it, the Televes LNB is white which is the correct colour for a LNB. So the Inverto might have slightly lower sensitivity to weak signals. The Inverto also has slightly worse polarity discrimination -23dB Inverto vs -25db Televes so maybe slightly less sensitive on signals with powerful opposite polarity signals. The Inverto local oscillator stability maybe slightly worse than my Televes, initial +/-1MHz, temperature drift +/-3MHz, working temperature -30 to +60 degrees C Inverto vs +/-2MHz, working temperature -30 to +60 degrees C Televes so maybe slightly more bit-rate errors particularly on narrow - low bitrate signals. But the most important spec is phase noise and on this crucial spec the Inverto has a much better lower phase noise -90dB Inverto vs -75dB Televes, low phase noise is crucial for good digital reception of weak signals as it is noise being added to the digital signal and on this spec the Inverto clearly beats the Televes. I will pick one up in the new year and see if it performs better than the Televes due to the lower phase noise. Professional LNBs have local oscillator stability measured in the kHz not the MHz and measure phase noise at 1kHz not 10kHz, so they maybe better. [/QUOTE]
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Fringe Reception General
Badr 4,6. 26 E
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