Paper as an absorber ?
Last Post: August 18, 2011:
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There are many posts and articles written about metal racks, roofs, and walls etc reflecting or otherwise "killing" radio waves.
What about paper? Does it absorb Wi-Fi signals?
I once read an article, some time ago, about such a phenomenon. Perhaps in environments such as libraries, raw newspaper stock, or telephone book storage areas?
Has anyone out there experienced such a thing?
Thanks.
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Paper overall is a good absorber of RF @2.4, never had a chance to check 5 but figure it probably similar. Books in shelving is usually not a problem, the metal shelving is what creates the issues. In order to see the absorption you have to have lots of paper, bulk rolls that are measured in tons and bigger than a VW microbus, it?s still not as bad as water, or better yet water (beer) in aluminum cans. Don?t think that there is any worse RF environment?
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I worked at the GP plant up here in Oregon for a time. While I will admit that was well before my wireless focused skill set I have now, I can tell you that even the bigger rolls caused little to no issue with wireless. It was the machines, metal walls, fork lifts being parked in front of the AP etc that caused havoc. There was very little difference in the new building prior to and after the paper started making its way through. I'd imagine a library though you'll have to go through several multi-layered isles with wood or metal shelving, so it could have a more cumulative effect.
HTH -
Maybe I should have been more specific, imagine a wall of paper rolls 4? thick 30? high, with an AP mounted above the ?wall of paper? 35?high and on the other side, 10? away from the paper, you?ll see about a 3dB drop, add another 4? of paper another 3dB, and so on. The point is that paper significantly absorbs the signal, and the reason you probably never noticed the problem with it is that the site survey took into account the ?walls of paper? correctly, and depending on the age of the radios in question the metal (multipath/refraction) would have been a potentially insurmountable obstacle to overcome, and would have caused perceptible issues with the wifi, todays modern radios really don?t have issues with multipath anymore.
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