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SolderSmoke Daily News

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Phase Noise and all that

Posted: 03 Jun 2022 07:10 AM PDT http://soldersmoke.blogspot.com/2022/06/phase-noise-and-all-that.html


Our friend Dave K8WPE has been listening to old podcasts. He recently came across those in which Pete and I were talking about phase noise. He asked
for some resources on this topic. Here is what I sent him:
Receiver performance expert Robert Sherwood explains it this way: Old
radios (Collins, Drake, Hammarlund, National) used a VFO or PTO and crystal oscillators to tune the bands. Any noise in the local oscillator (LO) chain
was minimal. When synthesized radios came along in the 70s, the LO had
noise on it. It is caused by phase jitter in the circuit, and puts
significant noise sidebands on the LO. This can mix with a strong signal outside the passband of the radio and put noise on top of the weak signal
you are trying to copy. This is a significant problem in some cases: You
have a neighboring ham close by, during Field Day when there are multiple transmitters at the same site, and certainly in a multi-multi contest
station. You would like the number to be better that 130 dBc / Hz at 10
kHz. A non-synthesized radio, such as a Drake or Collins, has so little
local oscillator noise the measurements were made closer-in between 2 and 5 kHz. http://www.sherweng.com/documents/TermsExplainedSherwoodTableofReceiverPerformance-RevF.pdfRhode
and Schwarz have a good oversight video with great graphs that explain the fundamentals, See above or here:
https://www.youtube.com/watch?v=hfgaEjf1154 I think a lot of the fretting
about advanced receiver performance measurements are really kind of over-the-top, and mostly of interest to advanced builders who want the very best performance from their receivers. Most of the rest of us are happy if
we can hear the band noise and separate the desired signals from the QRM.
But I must admit that as time goes on, I find myself getting more and more finicky. I start to worry about gain distribution and dynamic range. But
I don't worry so much about phase noise because I am more of an LC
oscillator guy and don't make much use of the PLL devices (like the Si5351) that do produce more phase noise.
I've had many articles on the blog about about phase noise. Here they are: https://soldersmoke.blogspot.com/search?q=%22phase+noise%22

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The Amazing Workshop and Test Gear of Tony Albus PE1ONS

Posted: 02 Jun 2022 03:51 AM PDT http://soldersmoke.blogspot.com/2022/06/the-amazing-workshop-and-test-gear-of.html


This is almost too much. This makes me want to go out and buy some more
test gear, maybe another scope, or a spectrum analyzer, or at least another DMM. I mean Tony has at least three of everything.
This is really amazing. Tony is obviously a test gear guy, but he also has
a ham call PE1ONS. He says he is not too active, but we should encourage
him to get more involved with ham gear. We need guys like him working on
ham gear. And he seems like such a happy person.
Here is his QRZ.com page: https://www.qrz.com/db/PE1ONS
Here is his awesome YouTube channel: https://www.youtube.com/TonyAlbus

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