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Screen Room; Was Mesh EMI ("Tempest") screens for the CRT of 453/454 Scopes
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Hi Harvey,
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I spent a year working in a "screen room" where I got to use Tek Spectrum Analyzers and the 549 Storage Scope. I was not impressed with the storage of the 549. I have learned since then how delicately the calibration has to be for storage CRTs so I appreciate them more now. Ours was not a "screen" room. More correctly it was a solid steel room with much better shielding than a screen would provide but we also had a true screen room as well. Of course all of the power was filtered as well. The only openings were small vents for cool air. Those were EMI certified as well. When I realized there was absolutely no way to signal for help if someone locked me in the room that really made me realize what an unusual place this was. Other than banging on the wall hoping someone heard me outside the room that was all anyone can do if you are ever locked in a solid steel "screen room". I never did figure out a way other than sound to get a signal or communication out of a "screen" room. It is an interesting problem. I wonder if anyone has come up with a solution. It was a very large "screen" room and we tested susceptibility to EMI as well as what our military black boxes radiated. It was very exotic stuff. We were testing according the current MIL Specs standard tests of the day. We also had a true screen room as well so I did spend some time in there. But you can always talk through the screen so getting help is no problem. Dennis -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Well, some of the screen rooms where I've worked had fiber optic connections to the outside world.? ?But they weren't the sealed steel like you describe, Dennis.
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Probably we can put this OT discussion to bed now. Jim F Sent from my Verizon, Samsung Galaxy smartphone -------- Original message --------From: Dennis Tillman W7PF <dennis@...> Date: 10/7/18 2:18 PM (GMT-08:00) To: [email protected] Subject: [TekScopes] Screen Room; Was Mesh EMI ("Tempest") screens for the CRT of 453/454 Scopes
Hi Harvey, I spent a year working in a "screen room" where I got to use Tek Spectrum Analyzers and the 549 Storage Scope. I was not impressed with the storage of the 549. I have learned since then how delicately the calibration has to be for storage CRTs so I appreciate them more now. Ours was not a "screen" room. More correctly it was a solid steel room with much better shielding than a screen would provide but we also had a true screen room as well. Of course all of the power was filtered as well. The only openings were small vents for cool air. Those were EMI certified as well. When I realized there was absolutely no way to signal for help if someone locked me in the room that really made me realize what an unusual place this was. Other than banging on the wall hoping someone heard me outside the room that was all anyone can do if you are ever locked in a solid steel "screen room". I never did figure out a way other than sound to get a signal or communication out of a "screen" room. It is an interesting problem. I wonder if anyone has come up with a solution. It was a very large "screen" room and we tested susceptibility to EMI as well as what our military black boxes radiated. It was very exotic stuff. We were testing according the current MIL Specs standard tests of the day. We also had a true screen room as well so I did spend some time in there. But you can always talk through the screen so getting help is no problem. Dennis -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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On Sun, 7 Oct 2018 14:18:28 -0700, you wrote:
The projects I was involved with did not have direct tempest requirements, although I got close to some. The company I worked for did have such EMI capabilities (at least a screen room), but I have no idea if they had anything else better. I rather suspect so, since they had some "black" programs that I know nothing about, even the names, but I do know that I was told they existed. For most equipment I had something to do with, I was designing for a factory floor, and that had nothing to do with shielding or EMI problems, we simply relied on the standard commercial ratings, grounding, etc. Storage scopes: I have a 214 that's been put on the back burner (very back.....) until I get a new input board (the input attenuator on channel 1 (I think) is bad, or the switch... can't replace that one). The storage tube itself produces a very dim trace (read none....) in storage mode. I do have a 7834 which seems to work ok, but for the most part, I'd rather go digital, simply because it seems to work more dependably. Yep, know that it doesn't capture between samples, has a nasty input filter, etc... If I need that kind of thing to look at, I'll use a 7103/7104 or a 16702B logic analyzer looking for transients. Harvey Hi Harvey, |
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