Re: Help on alarm

["Jim" <alarminex@xxxxxxx>]

JoeRaisin wrote:
> >
> >
> > Joe, are you recommending dual tec's in this configuration or just
> > PIR's?
> >
> > I wouldn't ...... unless the mfg of the dual-tec's have designed the
> > units to be used in close proximity to one another.
> >
>
> Not real familiar with Paradox, but I think they are PIR's.
> But my layout was with dual tech's in mind.
> A single unit at location *1 or dual units, one at the * in the upper
> left hand corner and one at location *2 would avoid the units seeing
> each other.

Hi Joe,

If I'm seeing it right in your drawing, the "array" of each unit will
still be in view of each other. The units don't actually have to be in
"sight" of each other. It's the beat frequency of the slightly
different outputs of each unit that will cause, what looks like a
doppler shift to either or both of the units, that will cause the false
alarms. With some manufacturers, they don't recommend that units be
within "range" of each other ( ie you must consider penetration of
walls etc) nor do they recommend units be mounted "back to back"
either. It's the "arrays" overlapping each other, even if they're not
within in the line of sight, that can cause the problems. And, for
example, you have to keep in mind that even in large areas like
warehouses, with, we'll say 2 units with 35 foot range, they *still*
should not be looking at one another closer than ..... say 90 feet or
more. Just because a unit is rated at 35 feet doesn't mean that it's
microwave array doesn't extend further. It just means that the unit can
detect movement of a body at that distance. The array can extend much
further than that.