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Fringe Reception Reports
Intelsat 35e 34.5 w
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<blockquote data-quote="s-band" data-source="post: 1025258" data-attributes="member: 407744"><p>If you change the sweep speed, you should see the modulation more clearly and if you can set your analyser to zero span with a wide bandwidth, triggered on video, you'll see the 20Hz. It looks random as the sweep is not locked to the modulation. The amplitude mod is a reasonable 20Hz sine wave. This plot shows it triggered on AM demodulated video <a href="https://www.satellites.co.uk/forums/attachments/34-5w_11665_slope-demod_h-gif.109789/" target="_blank">https://www.satellites.co.uk/forums/attachments/34-5w_11665_slope-demod_h-gif.109789/</a></p><p>To me, it looks like the signal from the opposite polarisation is modulated by 20Hz AM. That applies to both pairs.</p><p></p><p></p><p>This looks the same thing but a slower sweep speed. The waterfall shows that the AM is not locked to the sweep.</p><p></p><p>I wonder if there is something going on that is allowing signals from one polarisation to get to the opposite but modulated? Perhaps a problem with the switching matrix? or some diagnostics, as you suggest, Llew?</p></blockquote><p></p>
[QUOTE="s-band, post: 1025258, member: 407744"] If you change the sweep speed, you should see the modulation more clearly and if you can set your analyser to zero span with a wide bandwidth, triggered on video, you'll see the 20Hz. It looks random as the sweep is not locked to the modulation. The amplitude mod is a reasonable 20Hz sine wave. This plot shows it triggered on AM demodulated video [URL]https://www.satellites.co.uk/forums/attachments/34-5w_11665_slope-demod_h-gif.109789/[/URL] To me, it looks like the signal from the opposite polarisation is modulated by 20Hz AM. That applies to both pairs. This looks the same thing but a slower sweep speed. The waterfall shows that the AM is not locked to the sweep. I wonder if there is something going on that is allowing signals from one polarisation to get to the opposite but modulated? Perhaps a problem with the switching matrix? or some diagnostics, as you suggest, Llew? [/QUOTE]
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Intelsat 35e 34.5 w
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