DIY an EMC chamber... sort of... - Page 1
Forum section: electronics / rf-microwave

author: wilhe_jo
author_rank: Regular Contributor
timestamp: May 26, 2024, 01:45:36 pm
content: Hi!First of all, the way I'm exploring ATM is most properly unsuitable for 99% of you...Why? Actually I have bought a used chamber.The problem now is, that finding a suitable location is rather difficult.Most places offering me the 4,2m of height are either not heated, way too expensive or are just located in the middle of nowhere.Compared to those, normal office spaces around my current lab are rather affordable.So I thought, it would be worthwhile exploring if I could just put a Faraday-Cage into a normal office and get it lined with ferrites and absorbers.After reading 2 books, I'd say it would be worth the risk to build this rather unconventional chamber.Has anyone experience with such an endeavor?I'm sure, if I ring up Albatross and tell them what I intend to do with their nicely built monstrosity, they'll call me absolutely nuts...I intend to build a smallish FAR that should be at least close to fully-compliant EMC chambers.What I'm looking for are NSA/VSWR numbers for rather low heights.The 18" hybrid absorbers would give me a quite-zone of about 0,5x0,5x0,5m for typical room heights.However, bottom and top surfaces would be just 0,5m from that boundary... which should be okish as CISPR 16-1-4 mentions this min. distance several times...Any thoughts???BTW: This is kind of a backup-plan if I can't find a nice place within the next 6-9months... But actually, I start loving the idea to show my clients my DIY chamber

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: May 27, 2024, 06:47:17 am
content: you can certainly DIY one. DIYing onewell.. that's where it starts getting difficult

author: nctnico
author_rank: Super Contributor
timestamp: May 27, 2024, 04:59:50 pm
content: Offices typically have a false ceiling. Remove that (if possible / allowed) and you'll gain extra height. A while ago I visited a small EMC lab and the owner did something similar like you are planning. His biggest problem was making a structure strong enough to hold the weight of the door.

author: tszaboo
author_rank: Super Contributor
timestamp: May 27, 2024, 05:06:15 pm
content: Isn't most of the cost in the ferrite tiles? You can build it in, but then suddenly the equipment in it is worth more than the room, and most offices are rented. Plus based on the chambers I've seen, I have a feeling you need access to the backside of the wall for calibration/verification, but this is only a hunch.

author: wilhe_jo
author_rank: Regular Contributor
timestamp: May 28, 2024, 07:34:56 am
content: Quote from: tszaboo on May 27, 2024, 05:06:15 pmWell I have abt 5000kg of ferrites+ abt 40m3 of hybrid absorbers...just unloaded the truck yesterday morningThe problem now is to set it up with reasonable costs in the area I would prefer with a reasonable number of compromises.That's why I asked ABT NSA/VSWR values for chambers with low heights and small quiet zones... Usually you try to stay away from the absorbers by at least 80cm...so the original setup would be quite perfect even in a FAR configuration with 18" absorbers everywhere (I should be able to do a setup like this with all the stuff I got).However, I would be way easier to find a nice office space compared to something with 4,2m+ of ceiling height.Quote from: nctnico on May 27, 2024, 04:59:50 pmWell, the door is my biggest concern as well... But I may do a cheap, light door and have some structure on the inside to trap the leaking EM... I guess I should have enought absorber material for this.However, the overall weight is one of my concerns as well... I mean, some tons of ferrite...The good thing is, that I'll have about 9 months to find something....Btw: false ceiling gets you up to just 3,2m where I asked so far... Already okish, but not quite.73