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Posted by on June 9, 2005, 4:59 pm
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>Just an FYI, most wireless systems, if they are to meet UL requirements for
>resi or commercial burg (and fire too for that matter), are REQUIRED to send
>a supervisory report at least every hour which includes bits that tell the
>panel the batteries are low. UL requires that this signal is sent
>consistently every hour thereafter, and the battery must last for two weeks
>after the initial low battery signal.
I'm not talking about the panel but the sensors who are blown out when
Radio Frequency Interference (RFI) occur.
>As for interference, most panels if they are worth their salt include some
>sort of option which provides a time window after which, if the
>above-mentioned supervision signals are not received from EVERY sensor, the
>panel will notify the user and/or the central station.
I like your statement "option" and what about the others, how do they
react when RFI occur and muzzle incoming sensor signals?
By the way having that marvelous option that give a warning after a
long period is of no use or not efficient for intruders.
The long period is required to avoid false alarms and it give only a
warning that the system is bingo.
It don't solve the inability of the system to give any kind of alarm
because the sensor signals are no longer valid due to that RFI
muzzling problem anyway.
>Out of curiosity, which system was giving you this trouble?
>Craig B.
Its not a mater of type of the system, its a mater of radio data
communication who is unreliable/unusable when an other transmitter use
and block the sensor alarm convey frequency, the problem is known by
radio tech's as RFI.
ALL wireless alarm systems go bingo when RFI occur.
It seems that you didn't read my other posts about it.
>
>>
>> They are not reliable and are dead on warning when a transmitter
>> operates in a condition who muzzle the wireless alarm system.
>>
>> This is easily done with Radio Transmitters operating:
>> - ON the wireless frequency
>> - Saturating the receiver
>> - Intermodulation
>> - Harmonics
>> - Falling in the receiver bandpass
>> - On the IF frequency
>> - and more...
>> This is what i call basically Radio Frequency Interferences (RFI) but
>> in fact it covers, like you can notice above a lot more.
>>
>> In essence the problems is the fact that by no way two (or more)
>> systems can use simultaneously the same frequency, its called
>> collisions, interferences and more like you see above.
>>
>> The WORST is that the OWNER DON'T KNOW THAT HISS alarm system is no
>> longer operational, no message (20 years records hold by so called
>> experienced professionals: no RFI alarm).
>>
>> Use a wired systems and use WIRELESS only when impossible to wire, but
>> BE AWARE that YOUR SAFETY IS HAZARDOUS (my system was dead during more
>> than one year before i found out by accident and measuring the
>> wireless receiver output signal content).
>> Muzzling can occurs permanently or occasionally, mine was permanent.
>>
>> Note: So called low level mechanically (who claim them self
>> professional) try to let you believe that my system was dumb and/or
>> badly installed and they don't realize that it is an external
>> influences that can't be avoided whatever wireless alarm system you
>> have.
>> Its a pure radio communication problem know by telecommunication
>> specialists.
>> There is a way around for $$$ investments but that is out of reach of
>> a wireless alarm system.
>>
>> Paul
>> NOTE: My system is replaced with a wired one, do the same.
>>
>
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