Author Topic: EEVblog #1178 - Build a $10 DIY EMC Probe  (Read 2790 times)

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Offline floobydust

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Re: EEVblog #1178 - Build a $10 DIY EMC Probe
« Reply #50 on: February 12, 2019, 07:24:52 am »
It's 10 turns of #34AWG wire (0.16mm dia.) on a 1.5mm form, like a toothpick.
The murderous part is soldering the coax on one end, and the brass Faraday shield on the other. It was too flimsy, even with lots of epoxy.

If I was to revisit this, I would just buy a 0603 chip RF inductor and solder to it or make a slim pcb for the probe. I also was looking at adding a balun because the grounded (to spectrum analyzer) shield easily shorts to your PCB under test.
The R&S probe has an exposed, grounded bare metal tab which causes drama, sparks etc. for noobs.

A big area probe like OP, I do not find useful. Aside from finding an unshielded inductor or SMPS transformer gapped-core spewing flux, I'm usually looking at smaller things for EMC.

Offline joeqsmith

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Re: EEVblog #1178 - Build a $10 DIY EMC Probe
« Reply #51 on: February 12, 2019, 08:10:53 am »
Link to articles of the probes I handmade and use.   I use these without any sort of preamplifier.   They are good enough that I can normally isolate things to a single trace.
How electrically robust is your meter??

Offline wilfred

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Re: EEVblog #1178 - Build a $10 DIY EMC Probe
« Reply #52 on: February 18, 2019, 11:34:39 am »
I don't have a multi $1,000's spectrum analyser but I do have a Digilent Analog Discovery. Could you make meaningful measurements about a circuit with such limitations? Or with some other inexpensive device. One question I had was could you measure bypass effectiveness and therefore evaluate changes/improvements where needed? Even if only on a single or double layer board.

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