Does anyone have experience with faraday tape and is it good enough to block the signals in this video down to under 20uv, or .02mv if all exposed metal with signals running through it are covered?

https://www.youtube.com/shorts/a_6VX3qjvsE

 

Does anyone have experience with faraday tape and is it good enough to block the signals in this video down to under 20uv, or .02mv if all exposed metal with signals running through it are covered?

https://www.youtube.com/shorts/a_6VX3qjvsE

Block it from what, a high impedance scope probe? That video shows that level of 'cross-talk' is harmless to typical SPI clocked signals.

 

The link did not work for me, I got junk advertising. Unless the "shield Tape" is very conductive it will be A WASTE OF MONEY. Aluminum foil tape, like used in some cables is quite good.
What do you want to shield?? Can you describe the intended application, please? There are a lot of experienced and very smart folks participate here. They have good answers.

 

This video is pure bull***t! There is an SPI clock signal with some MHz sent over more than 10 cm wire to a proto board with some additional contact lengh inside and a resistor as an antenna. Of course you can see a amplitude of only about 5 mV on the high impedance probe tip of a scope which has another resistor as receiving antenna. This has nothing to do with crosstalk, this is just the priciple of radio transmission.

 

That YOU-TOOB link still puts me into pages of garbage.
And a product certainly gives an impression based on the company it keeps!!!

Besides that, in all of my long electrical career I have never used any such product for shielding effect. I HAVE designed and specified a whole lot of low level circuits that were successfully shielded from interference. NONE OF THEM used that sort of product!!
I HAVE SEEN shielding tape used inside large screen color displays, that tape did have an aluminum surface.

Possibly a somewhat conductive tape will serve to drain static charges and protect sensitive semiconductor devices. THAT APPLICATION is totally different from preventing electrical noise pickup. Static protection coatings are quite common and serve a totally different purpose!

 

Welcome to AAC.

There seems to be a lot of confusion here, starting with the video. The poster refers to the radiation from an unterminated, unshielded 20MHz source as "crosstalk". It's not.

Crosstalk when two or more communications channels are colocated (such as in the case of multicore wire carrying distinct channels). When a signal from one is superimposed on another it "talks across" which can be via induction or radiation—the key is that the information from one channel is appearing in the other channel which will cause distortion of the latter.

The video is showing something different. In that case we have a radio signal that is being transmitted by the unterminated/improperly terminated and unloaded wire and received by a very high impedance scope probe. The high impedance means there is effectively no load presented by the scope and so while there is voltage measured by the scope the current is so close to zero as makes no difference.

This is an entirely artificial situation and has nothing to do with practical concerns about shielding. Let's say there was such a 20MHz signal and you had a device that couldn't tolerate it, and somehow needed to keep it isolated. What would you do?

First, placing the device in a Farady Cage of some sort is a good start. A metal box with galvanically connected sides and lid—that is, all panels electrically connected and that has a low impedance connection to an earth ground or something that can act as a sink for the signals being imposed on the box will reduce or eliminate the offending signals.

How you connect the panels together is not particularly important, and they don't have to be rigid, or even a box, per se. Wrapping it in metallic foil would work. The keep is no openings large enough for the wavelength of interest. For 20MHz, with a wavelength of about 15m, an enclosure with openings λ/10 ≈ 1.5m (rule of thumb for no obvious coupling) would suffice and openings λ/100 ≈ 15cm should provide shielding of ≳40–60dB.

The openings in an enclosure can act as slot antennas so reducing them in size makes a big difference in isolation. But the biggest issue for shielding is penetration of the enclosure by conductors. Depending on the signals carried by these conductors, feed through capacitors, ferrite beads, and common mode chokes can block the signals.

"Tape" is not an answer, it may or may not be useful—proper specification and construction of the shielding based on the frequencies of concern and the device(s) involve is the answer assuming there is a problem.

The truth is, the demonstration in the video shows nothing about whether you will have a real world problem with SPI signals.

 

It looks he's using his scope probe as an antenna so what's the surprise here?

 

Just like a number of us have rather bluntly stated: Anti-static resistive tape is not a correct answer. Cross-talk is unintended coupling of signals, while a much broader term is INTERFERENCE, which is the unintended entry of any sort of voltage into a signal. AND, based on the description of the video, is usually much different than that fake show.