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Posted by on July 2, 2005, 11:24 am
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Surprising.
Can you mention what part of EMC testing covers RFI?
What's certified test equipment is required to do what
YOU CALL RFI tests or is it the same certified general coverage
generators and/or power line test equipment?
Can you tell me where the answer has been given dear stupid so
"called" pro?
>wrote:
>This is just semantics. If all that is left for you to argue is the choice
>of letters used then this is the end of the thread as far as I am concerned.
>I was attempting to write so that you would understand. As part of the
>immunity tests carried out for EMC legislation the equipment is tested for
>immunity over a wide frequency range. This is often described as RFI = Radio
>Frequency Interference when the equipment fails. I have been open field EMC
>testing on several occasions and it is referred to as passing or failing RFI
>even though it is part of EMC immunity tests. It's a choice of words. Both
>work and are understood by most.
wrote:
>Newbies...
>
>Don't trust anything this child posts.
>
>He has ignored all of the reponses that he has been given in the past from
>people who know what they are talking about. I won't bother to go through
>this post and correct his mistakes yet again, but trust me he's a complete
>moron with no education.
>
>
>
>>
>> Don't thrust wireless alarm systems, use wired!!!
>>
>> My wireless alarm system was:
>> - "deaf", muzzled for sensor signal reception
>> and
>> - "dead" on alarm giving
>> when i used a simple commercial available wireless radio headphone,
>> that simple ..
>>
>> Its a well known radio transmission problem called "Radio Frequency
>> Interference" (RFI)
>> - present at ALL systems (old and new = external) but
>> - more present than normal in wireless alarm systems due to the low
>> power transmitters (10milliWatt) used in the sensors
>> AND
>> - the use of shared frequencies (obliged) who have disturbances and
>> are unprotected for RFI (see at FCC and/or other country authorities
>> for the world frequency band attribution scheme or www.ero.dk for
>> official info).
>>
>> What type of signals are able to jeopardize they're operation?
>> External RF Transmitters operating:
>> - ON the wireless frequency
>> - Falling in the receiver band pass
>> - On the IF frequency (IF = Intermediate Frequency)
>> - Intermodulation
>> - Saturating the receiver front end circuit
>> - Harmonics
>> - and more...
>> In essence the problems caused by interference is the fact that by no
>> way two (or more) systems can use simultaneously the same frequency.
>>
>> My wireless headphone story showed me "how simple it is" to have the
>> operation jeopardized completely by an external transmitter operating
>> on the wireless alarm frequency.
>>
>> This problem is NOT REPORTED by any mean to the owner, realize what
>> can happen when you have a wireless FIRE detection system...
>> The system will no longer detect it (same for intruder alarm).
>>
>>
>> I replaced my Wireless Alarm System with a wired one; the problem is
>> solved for me, what about yours?
>>
>>
>> Some "extra clever pro's" say that the FCC (++) will locate and find
>> the disturbing signal.
>> 1. Just realize that the local range of the disturbing signal don't
>> allow to locate it at distance.
>> 2. That other legal users share the wireless alarm frequency
>> and that they have to find out in that bunch the one whom is
>> disturbing... Good luck.
>>
>> Paul
>>
>
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