Hello everyone,
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This is a more generic request for help that impacts everything I am doing in my shack with my older Tektronix 200 Mhz analog o-scope. Specifically, I have been seeing a "noise" in the last few weeks that I don't recall seeing before...although it is possible it was there and I just was not seeing it because I was looking at larger signals. Not sure about that.
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But here is what I am seeing... in connection with developing a 30M local oscillator for a homebrew design... when I view the intended signal on my scope at ~10 Mhz, I am seeing superimposed on that sine wave a lower level signal that appears to have 8 periods for every period of the main signal. It's low level but very noticeable on the scope. That would put the noise at around 80 Mhz.
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At first I thought I had an internal problem with my scope, or my probes, or... whatever. But I have now seen the signal with a second scope and several different probes. Then thinking it was some weird product of my oscillator design, I looked at a signal from a signal generator, and saw the exact same noise. Multiple probes, two different scopes, and a couple different signal sources, and I still see it.
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So now I suspect some source of noise in the 80 Mhz range in my shack or neighborhood that my mesaurement system is picking up. I have no clue what this would be. Any thoughts? Has anyone else ever experienced something like this?
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If we need to find an excuse for this to be addressed in this group, I recently built a QCX+ for 30M as my "benchmark" for my own design comparison... LOL... hopefully that's good enough.
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73 & TIA,
Joel W9JFK
