RF Noise - Do you notice the RF noise floor has greatly increased with the influx of wall warts?

Cquk 10 months ago

I would be interested to see if any one else has noticed the issue. Maybe if you work on RF devices / have a spectrum analyiser etc.

Even some bench PSU's seem to produce more EMI than i would expect.

I am working on adding Ferrite's to all my cables but where does it stop?

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Cquk 10 months ago +2

Hi All Update I have found a tool to Identify the source of the noise: https://www.sdr-kits.net/index.php?route=web/pages&page_id=113_113 I will report back once I build it.
DAB 10 months ago +1

They are built cheap, not as a quality power product.
dang74 10 months ago +1

I suspect that a noisy supply would manifest itself in the form of amplitude modulation which could raise the noise near any RF tones you're creating. It also wouldn't surprise me if you're seeing side…

Cquk 10 months ago in reply to strb

Do you have any info on the seminar sounds interesting ? This is just what I am trying to track down. Right now it’s everywhere.
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bidrohini 10 months ago

You can Add decoupling capacitors and proper filtering at the power input stages of your RF devices. It can help block noise from entering sensitive circuits.
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strb 10 months ago in reply to Cquk

I don't have particular informations on your specific problem but yes, the seminar was very interesting. Basically anything that has inside a switching converter, if badly designed, could lead to added noise (conducted and/or radiated). Probably phone chargers and led lamps are the major issue as they tend to be on the cheap side.
Have you tried to switch "all off" and then on one thing at time to see how the noise level changes? Maybe you can identify one or two major offender if you're lucky.
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DAB 10 months ago in reply to Cquk

Yes, in the old days, you could buy quality power supplies that were very steady and produced very few artifacts.

Sadly those days are gone as we have mostly inexpensive devices that just barely suffice.
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vmate 10 months ago in reply to bidrohini

It's not really the power input to RF devices that's the issue, it's RF noise coupling into circuits from different devices.
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battlecoder 10 months ago

I've noticed this too. Since I got interested in EMI and RF I've been replacing low quality wall warts and adapters that I've noticed that are particularly noisy. Some of them are one mixer away from being actual radio transmission devices.
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Cquk 10 months ago in reply to battlecoder

100% do you have any pictures of the ones you have found to be really bad. I just purchased a test tool to Identify these. I will report back as to how well it works.
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battlecoder 10 months ago in reply to Cquk

I might have a couple in a box. Will check and take pictures if I find them.
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Cquk 10 months ago

Hi All

Update I have found a tool to Identify the source of the noise:

https://www.sdr-kits.net/index.php?route=web/pages&page_id=113_113

I will report back once I build it.
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beacon_dave 10 months ago in reply to Cquk

The Tapir E-smog detector may be of interest.

Tapir - Ultrasensitive wideband magnetic/electromagnetic field detector
https://www.elektormagazine.com/labs/tapir-ultraensitive-wideband-magneticelectromagnetic-field-detector

TAPIR – E-smog detector
https://www.youtube.com/watch?v=M-q37LKKzrI
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