Re: Security systems

[Nigel Orr <nigel.orr@xxxxxxx>]

At 10:48 26/02/99 GMT, you wrote:
>on battery-powered sensors. In the past I have heard of systems which
>eat Duracells at the rate of several every month!

I think the previous resident of our house had one of these- she spoke
glowingly of how the installers were ever so helpful and checked it all for
her regularly, but they didn't appear to have told her to replace the
batteries- when we moved in, _every_ _single_ _battery_ was flat!

>lifespan is true, then I could well be persuaded to reconsider my
>position - I reckon I could live with annual maintenance/replacement as
>opposed to monthly...

Sounds more reasonable, but...

>So, My first question is: does anybody have experience of this system,
>good or bad, and can anyone vouch for the battery lifespan claims?

I wouldn't touch one with a bargepole _unless_ I was renting and wanted to
take a system away when I left, or in a house with solid walls and floors
throughout, and no place to hide cables.  I'm probably unusual in being
happy and competent to hide cables, from previous postings to this list...
;-)

A wired system is cheaper, for the same quality, there's less to go wrong,
you can run wires for other HA stuff at the same time, etc etc etc- but the
wireless devotees will doubtless come up with equally compelling reasons
for wireless- I would suggest you listen to both, then decide for yourself-
if one was really clearly provably superior in every case,
alt.security.alarms wouldn't have been bickering about it for the last n
years...

IMO/IME, It's just too easy for them to get jammed/confused- there are
basically 2 options for domestic-grade boxes, you can either have them
paranoid so that when the local taxi firm goes past they start calling the
police, or you can have them 'chilled out', which leaves them open to
legitimate jamming/ transmitters being disabled etc.  Future technology (eg
spread spectrum) could change all that, but, for now, I don't feel they are
so reliable as cable.  Add to that the fact that you are reliant on one
manufacturer to keep producing matching spares/upgrades as you want to
expand it, and that they may be unable to do that if RF bandwidth
allocations change in the future (as they undoubtedly will)...

>Secondly, I've seen lots of good things written about the Napco Gemini

Likewise, particularly for it's connectability

You could check out www.dejanews.com- there was discussion of alarms in
uk.d-i-y not long ago.  You could also check out alt.security.alarms for
more hints- there are some UK folks there.

Hope that helps,

Nigel
--
Nigel Orr                  Research Associate   O   ______
Underwater Acoustics Group,              o / o    \_/(
Dept of Electrical and Electronic Engineering     (_   <   _ (
University of Newcastle Upon Tyne             \______/ \(

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