Post by Peter LawrencePost by n***@sbcglobal.netPost by Peter LawrencePost by Royhttp://www.networkworld.com/article/3075024/mobile-wireless/fcc-formalizes-massive-fines-for-selling-using-cell-phone-jammers.html
Think of this as revenue enhancement.
Post by Peter LawrencePost by n***@sbcglobal.netPost by Peter LawrenceIt it legal to block cellular waves inside buildings by building Faraday
cages within the walls of the building?
- Peter
I think one of the reasons some of us can't get good cellular reception inside
our houses but okay outside is due to foil lined insulation.
We are already living in Faraday cages. :-D
It's worse in some older homes and apartments that used chicken-wire
combined plaster of Paris for their interior walls.
:)
- Peter
Sorta. Most lath and plaster walls use wood strips with gaps to hole
the plaster in place. The plaster has some water in it, so it will
attenuate some RF. However, ceilings need more support so they used
expanded metal lath and plaster construction:
<http://inspectapedia.com/interiors/Plaster_on_Expanded_Metal_Lath.php>
That blocks RF quite nicely. There's also stucco and chicken wire on
exterior walls. Inside, we have aluminum foil backed insulation in
the walls, floors, and ceilings. Some decorative wallpaper has an
aluminum foil backing.
I have to deal with one customers house that was custom designed and
built buy a former fire chief. The house is divided into 3 sections
upstairs plus one more downstairs. No RF gets between any of the
three sections. I have 4 wireless access points installed, one for
each section. Even the doors have metal inside (to prevent the spread
of fire).
Anything built after about 1995 in California has a Low-E (low
emissive) coating on all the glass windows, doors, skylights, etc. The
idea is to reflect UV and IR and still pass visible light.
<http://www.efficientwindows.org/lowe.php>
The problem is that most coating also block RF frequencies. Some
details on TiNi coating:
<http://802.11junk.com/jeffl/crud/Low-E-titanium-nitide-glass.pdf>
A few years ago, UCSC built 3 new buildings on the campus. To deal
with earthquakes, the fascia on new buildings needed reinforcement.
That's usually done with a welded wire mesh in the concrete fake brick
as backing or something similar. Yet another block to RF. UCSC
fortunately has a DAS (distributed antenna system) which was
configured to leak some RF inside the building so cellular would work.
--
Jeff Liebermann ***@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558