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Re: Somewhat funny stuff
Ask them to post a picture of the PIR. LOL.
"ABLE1" <royboynospam@xxxxxxxxxxxxx> wrote in message
> Found this discussion over at alt.electronics. Those Brits are all the
> rage some times.
> Kinda enjoyed the read and thought I would share.
> We have a wireless network at work which appears to have gone downhill
> since the workmen installed PIRs for the burglar alarm. One of them in
> particular appears to cause dropped packets the closer a laptop is to it.
> Is this possible?? It's not a wireless PIR as far as I know, as I can see
> some leftover cable he was using which is a multicore (about 10 cores)
> type similar to phone systems, so I assume this is for the signal aswell
> as power. The person in that office swears blind that there were
> absolutely no problems until the PIR was installed above her desk, and now
> when I check, about 60% of the packets are being dropped. Moving her
> laptop to the opposite side of the room it drops only 5% of packets. PIRs
> used to just pick up infrared of your bodyheat, but I think now they are
> also motion sensors? Perhaps this means they are sending out a signal and
> bouncing it off you? Perhaps this could interfere with wireless
>> You can now get ones that use microwave detection as well as PIR, they
>> are called "Dual PIR" sensors:
>> 10.5GHz for the microwave
>> A normal PIR sensor would not cause any issues like this as they are
>> You can simply swap a Dual PIR for a normal PIR no probems.
> Good point, I'll just tell them to put in a passive in any rooms with
> problems if I can prove it's that.
> We've always had detectors though and never had problems, so maybe it's
> faulty? Or the new ones are on a different band. If it's using 2.4GHz,
> in my opinion it's wrong. Using the same band as wireless networks in an
> office is just plain stupid.
>> Sensors only need a 4 conductor cable, two for power (12V), two for the
> Odd that they left a bit of approx 10 core cable then (and that was the
> only thing they were fitting at the time). Unless it uses a different
> core for each type of detection?
> A normal PIR sensor would not cause any issues like this as they are
> You can simply swap a Dual PIR for a normal PIR no probems. Sensors
> only need a 4 conductor cable, two for power (12V), two for the
>> If its PIR it shouln't.
>> PIR is Passive Infra Red, and it's body heat which triggers the sensor,
>> not anthing the device transmits.
> I'm not sure if it's PIR or not. Aren't a lot of them nowadays
>> Maybe the wiring is affecting the strength of the RF field areound where
>> she sits.
> The wiring? It shouldn't have that strong a field from its wiring surely?
> The effect is as such: within about 2-3 metres the network is unusable.
> The next 2-3 metres it works most of the time. After that it's almost
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