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Ken,

I also noticed a clean output after the LPF with Phase noise as well, but I also noticed a lower background noise floor in receive, in fact I'm very happy with it now. If it wasn't for the hiss of the LM386, it would be a most quiet receiver.

Joel?

KB6QVI

On Jan 4, 2017, at 6:07 PM, Ken Chase chase8043@... [BITX20] <BITX20@...> wrote:

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Joel when you say noisier, do mean sounds noisier or scope trace is noisier? I built the top filter and I didn't hear any difference. On the scope, the signal cleaned up good, but I could see some phase noise.

73

Ken VA3ABN

On Wed, Jan 4, 2017 at 8:26 PM, Joel Caulkins caulktel@... [BITX20] <BITX20@...> wrote:

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Andy,

Mine was noisier too until I put a LPF inline with the Si5351. I got the idea here. Scroll down the page a ways to find the filter table.

Joel KB6QVI

On Jan 4, 2017, at 5:01 PM, ahecker@... [BITX20] <BITX20@...> wrote:

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I noticed that my receiver got noisier when I disconnected the built-in VFO and added the Si5351.? I get that a filter re-shapes the waveform, but I'm wondering about whether it's useful to clean the output signal a bit before injecting it into the radio.

I guess this is where the 'experiment' and 'learning' parts of the game happen. :)

Andy