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<blockquote data-quote="s-band" data-source="post: 1143363" data-attributes="member: 407744">[USER=215446]@deeptho[/USER]It's hard to diagnose using a DVB card, do you have a specrum analyser? Even an RTL-SDR stick would be a useful tool.If the spikes appear at different places on each sweep, it could be instability or pulse interference at RF or IF. Does it do it when off the dish? If so, does it change dramatically if you put your hand over the feed or any part of the LNB? If so it may be instability. If it only does it when pointed at a satellite, it may still be instability but it could be pulse interference at RF or IF. If at IF, I'd expect you to see it on other LNBs unless the IF cable was damaged.I've seen a couple of problems with C band LNBs:<a href="https://www.satellitescommunity.de/forum/index.php?thread/1049-norsat-3220-c-band-lnb-warning" target="_blank">This one</a> doesn't look like yours but it may be worth making sure the 22k is off. It happenedwhere the 22kHz filtering is non-existent and the LO becomes modulated by the 22k.Another is where the front end is unstable with particular matches. The Zinwell C band LNBs seem susceptible to this, see <a href="https://satellites.co.uk/forums/threads/av-comm-polariser-zinwell-lnbf.169433/post-1004590" target="_blank">Just Sharing This - AV-Comm Polariser + Zinwell lnbf</a>Many cheap C band LNBs, including Titaniums, seem to be close to instability .</blockquote>

[QUOTE="s-band, post: 1143363, member: 407744"] [USER=215446]@deeptho[/USER] It's hard to diagnose using a DVB card, do you have a specrum analyser? Even an RTL-SDR stick would be a useful tool. If the spikes appear at different places on each sweep, it could be instability or pulse interference at RF or IF. Does it do it when off the dish? If so, does it change dramatically if you put your hand over the feed or any part of the LNB? If so it may be instability. If it only does it when pointed at a satellite, it may still be instability but it could be pulse interference at RF or IF. If at IF, I'd expect you to see it on other LNBs unless the IF cable was damaged. I've seen a couple of problems with C band LNBs: [URL='https://www.satellitescommunity.de/forum/index.php?thread/1049-norsat-3220-c-band-lnb-warning']This one[/URL] doesn't look like yours but it may be worth making sure the 22k is off. It happened where the 22kHz filtering is non-existent and the LO becomes modulated by the 22k. Another is where the front end is unstable with particular matches. The Zinwell C band LNBs seem susceptible to this, see [URL='https://satellites.co.uk/forums/threads/av-comm-polariser-zinwell-lnbf.169433/post-1004590']Just Sharing This - AV-Comm Polariser + Zinwell lnbf[/URL] Many cheap C band LNBs, including Titaniums, seem to be close to instability . [/QUOTE]

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