3 ms·

These don't do anything on their own. You need to couple them with a spectrum analyser - another $1k+. I've used these for hunting down problems with EMC on a

These don't do anything on their own. You need to couple them with a spectrum analyser - another $1k+. I've used these for hunting down problems with EMC on a PCB. They're quite useful, but it's hard to get a good picture of whether the device will actually fail or not based on the results. Generally if you put one of these near a switching power supply it'll go crazy, but that doesn't necessarily mean that the device will fail EMC testing. You really need a far field antenna with some sort of calibrated source to really know how you're doing.

e-_pusher 7y ago
You can still get pretty far with an RTL-SDR attached to them, which can be had for $25. I have successfully debugged radiated EMI issues with the combination of these two: https://www.amazon.com/seeed-Studio-RF-Explorer-Antenna/dp/B077K2J8H2/ref=sr_1_2?keywords=near+field+antenna+kit&qid=1574714557&sr=8-2 https://www.amazon.com/seeed-Studio-RF-Explorer-Antenna/dp/B... https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Defined/dp/B0129EBDS2/ref=sr_1_4?keywords=rtl-sdr&qid=1574714580&sr=8-4 https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Define...
- opwieurposiu 7y ago
  What was the culprit? IME noisy switchers are easy to find, Improper signal termination impedance hard to find.
- peter_d_sherman 7y ago
  Nice!
peter_d_sherman 7y ago
"These don't do anything on their own. You need to couple them with a spectrum analyser - another $1k+." Yes, I knew that you'd have to hook them up to an RF / frequency analyzer of some sort. Each of these probes is really just a small antenna with specific characteristics, is it not? "Generally if you put one of these near a switching power supply it'll go crazy" Hmm... interesting information... the physicist in me says that perhaps there's a relationship here between electrical power and all sorts of frequencies at the same time... but that would be only a hypothesis without testing it... is it the electrical line that generates these conditions, or the conversion of power... some power supplies up the voltage, then convert it down (sort of like the way PWM supplies more power to a PC's fan by sending more pulses per unit time)... so maybe this is where all of the electrical noise (aka, many frequencies at the same time) are... I woudn't know, but I would think there are some experiments to be done in this area... Anyway, super interesting!

e-_pusher 7y ago

You can still get pretty far with an RTL-SDR attached to them, which can be had for $25. I have successfully debugged radiated EMI issues with the combination of these two: https://www.amazon.com/seeed-Studio-RF-Explorer-Antenna/dp/B077K2J8H2/ref=sr_1_2?keywords=near+field+antenna+kit&qid=1574714557&sr=8-2 https://www.amazon.com/seeed-Studio-RF-Explorer-Antenna/dp/B... https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Defined/dp/B0129EBDS2/ref=sr_1_4?keywords=rtl-sdr&qid=1574714580&sr=8-4 https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Define...

opwieurposiu 7y ago
What was the culprit? IME noisy switchers are easy to find, Improper signal termination impedance hard to find.
peter_d_sherman 7y ago
Nice!

peter_d_sherman 7y ago

"These don't do anything on their own. You need to couple them with a spectrum analyser - another $1k+." Yes, I knew that you'd have to hook them up to an RF / frequency analyzer of some sort. Each of these probes is really just a small antenna with specific characteristics, is it not? "Generally if you put one of these near a switching power supply it'll go crazy" Hmm... interesting information... the physicist in me says that perhaps there's a relationship here between electrical power and all sorts of frequencies at the same time... but that would be only a hypothesis without testing it... is it the electrical line that generates these conditions, or the conversion of power... some power supplies up the voltage, then convert it down (sort of like the way PWM supplies more power to a PC's fan by sending more pulses per unit time)... so maybe this is where all of the electrical noise (aka, many frequencies at the same time) are... I woudn't know, but I would think there are some experiments to be done in this area... Anyway, super interesting!