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NNTP-Posting-Date: Sat, 19 Oct 2002 20:35:35 -0500
From: "Dave VanHorn"
References: <email@example.com> <5HGdnaFia_mUHC2gXTWc3A@comcast.com> <firstname.lastname@example.org> <email@example.com> <3DB20482.C97D0D7A@mfi.net>
Subject: Re: Radar basics?
Date: Sat, 19 Oct 2002 20:35:35 -0500
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> Some high end PIR detectors have a microwave detector built it to
> prevent false alarms from air currents when the heat or AC kicks in.
Yep. Dual-Tek is one brand. A fairly good idea, though it also means a lot
more components to fail.
> I used some on a college campus a few years ago. The microwave sensor
> kicks in for a fraction of a second to look for motion, then shuts down
> if it doesn't find anything. That makes it harder for someone to locate
> and disable the security system.
I never worked with a switched one. Interesting idea.
I always used overlapping patterns, and a few tricks of the trade to protect
Cheap keyswitch on a plate outside, with lit leds that change when the
system is armed or not.
However, picking the cheap lock and rotating the switch will not have the
Mount the sensors on interior walls, and never run wiring outside that area.
Pop a sensor or two above the ceiling tiles in sensitive areas.
Wire running up a wall to a bell box. Of course the wire has nothing to do
with the bell box at all, and it would be a bad idea to significantly alter
Always, keep the control panel in a difficult spot. There's few control
panels that will survive a hit from a fire axe.
Never did this one, but a bad panel, mounted in a visible spot with working
LEDs would be an easy (and wrong) target.
The basic idea is to give them what looks like an easy way in, that is in
fact sensored so that they trip the system while they are still outside.
The visible sensors may or may not be the active ones, and there are always
more sensors that you won't see.
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