This was a laugh until I realized he was serious

Behold: a scope with a tin foil hat!

-- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.)

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The 7104 was available with an option of extra screening ( extra fingers on covers and plugin bays, caps on all unused BNCs and a fine wire mesh over the CRT face). The published photo (if it is a screen photo), doesn't show any mesh.

The readout is funny, too. Shows using right hand vertical amplifier, lower trace, but no upper trace sensitivity showing. Even if the upper trace is shifted off screen, its readout should still be there. There is no timebase readout at all. Either the 7104 or its plugins are faulty, or (I hesitate to suggest), some massaging has taken place betwixt camera and published photograph.

I don't know the EM field strength necessary to produce effects like that on a 7104, but instinct says it's a helluva lot. I'd want to be inside a Faraday cage, along with the instruments.

Even with its covers off, I've never noticed any external field effects with my (EMC option) 7104.

That's because those were designed by the good old crew. The most embarrassing event happend at a client with a rented upscale analyzer from Agilent. This was specifically mentioned as suitable for the EMC market (!) which is why they rented it, even though I had asked them to rent one that is at lest 20 years old. Long story short, lots of "trees" showed up at VHF. I couldn't find most of them with the near field probes in their system. Sooo ... walked over to the analyzer, held the near field probe in front of its LCD screen and they all lit up, big time. Asked where the next HW store was, drove over there, bought chimney spark screen, snipped and formed it, draped it over the analyzer ... all the peaks were gone. Ok, they did have Jumbo Polish at the hotdog stand in front of the HW store which was a nice lunch. Full confession: I had two of those, with lots of the green relish ...

For some things such as red wine, software and lab equipment older usually means better.

First confirmation of electron time - travel!

--Winston

This guy knows his stuff. Maybe you should try to read the article with less cynicism and try to learn something.

Yes, he knows his stuff and I've read just about every article he has available. I think you misinterpreted my comment or I was unclear as to what I meant.

The 'scope picture was so strange that I laughed out loud when I saw it. At first, I thought he made it up to grab attention (which it did). Then, upon reading the article, I saw he was serious and that it was not a joke.

Have you read all of his articles?

That may be, but I find his offscreen photograph of the 7104 display suspicious, for reasons I have already stated.

To produce the effect shown, including partially shutting down the readout of a 7104 must take a field strength in the thousands of volts per meter. Nobody would seriously expect any instrument to behave under those conditions.

I thought it was a joke at first glance. But it looks real to me (if very strange).

Most of his site is about the fact that even apparently trivial ESD events can create momentary very high currents and fields. IIRC the IEC standards for calibrating ESD testers do indeed put the scope in a faraday shield.

Wow, that is some arbitrary waveform generator he has there. Even time is arbitrary. I want one.

Do you think MAYBE the ESD event causes the X amp to go crazy? I'm sure he can't mean that is the actual waveform of the event.

Yup. Or at least the ESD event causes the trace to jump all over the screen.

That's the point of the article - that EMI can make measuring instruments fail to represent the reality of what's being measured.

Sylvia.

I knew THAT, but *I* have never seen such an event make a scope channel do anything like what he showed.

I've been on one of his courses and in my view he knows what he's talking about. He showed us various effects with real equipment, cables, PCBs in a hands-on lab and it taught me a lot.

Nemo

It looks to me like it was intended as a gag, but just wasn't very funny.

Cheers! Rich

Maybe whatever you're on is wearing off. Try another.