Re: what is the best wire for a perimeter alarm

[Tommy <tommy@xxxxxxxxxx>]

Jim <alarminex@xxxxxxx> wrote in
news:1190055655.355159.246040@xxxxxxxxxxxxxxxxxxxxxxxxxxx:

> On Sep 17, 11:32?am, "Bill" <bill190nos...@xxxxxxxxx> wrote:
>> "Sue"  wrote in message
>> > My brother-in-law, who is an electrical engineer, would wake up
>> > from a nap in his easy chair and walk to the kitchen thru the beam
>> > of his PIR only to have his alarm start wailing.  "Wait", he said
>> > to himself, "I didn't arm the system!"  After this happened several
>> > times, he began to wonder, what in the heck is going on that could
>> > arm my alarm?  One evening immediately after this happened, he
>> > mosied outdoors, and lo and behold he could hear his neighbor
>> > talking on his ham radio.  Said neighbor had antennas all over the
>> > outside of his house.  Ron had not used shielded wire for his
>> > alarm system. He re-wired that weekend, and problem was solved.
>>
>> I had a problem with a TV remote extender not working (Operate the TV
>> remote from another room). So I enclosed the transmitter in a metal
>> box, receiver in another metal box (Faraday cages), leaving small
>> holes for the light to go through, then connected a shielded coax
>> cable between them. Then it worked just fine.
>>
>> The receiver had a light which indicated it was receiving a signal
>> from the transmitter. Well this light was going almost constantly
>> even though the transmitter was off! And this was jamming the real
>> signals so the extender could not work. After I shielded everything
>> (from external RF), the light on the receiver stayed dark unless the
>> transmitter was activated.
>>
>> Anyway lots of RF around - at least where I live...
>
> If you have an RF problem, then it may (meaning maybe)  be addressed
> with shielded wire. But there are other solutions that might work that
> would be much simpler to impliment.
>
>
> The point that is trying to be made regarding shieled wire is that it
> may solve specific problems. However, if used indiscriminately , it
> can cause problems. Even when called for, it can cause other problems
> that have to be addressed, in addtion to the original problem. If a
> mfg has specific requirements to use shielded wire from feed back from
> the field or by design, they'll certainly tell you to use it.
> Otherwise, if not recommended, the overwhelming odds in favor of NOT
> having a problems is the best way to proceed.
>
> Use what the manufacturer recommends and if you have a problem,
> address the specific problem and if it calls for a shield or a choke
> or a capacitor ..... try what ever is recommended until the problem is
> solved. If you start out with solutions to problems that don't exits,
> you'll greatly increase the possiblity of creating issues that
> wouldn't have existed had you followed the mfg's recommedations.
>
> Whew!
>
>

Gee,
That was a long post for you. is roland rubbing off on you?