[RFI] Alarm Systems and EMI/EMC

[WA3GIN]

I got around this security problem by going to all CCTV analog, coax fed 
cameras.  With motion detection the system saves the first couple of minutes 
of video prior to the trigger event, then emails me a jpg of the trigger 
event and save the following five mintues after the trigger event.  Great 
for protecting weekend retreats, etc. No issues with RFI. www.geovision.com 
for details.


73,
dave
wa3gin
----- Original Message ----- 
From: "Michael Tope" <W4EF at dellroy.com>
To: "Jim Brown" <jim at audiosystemsgroup.com>
Cc: <RFI at contesting.com>
Sent: Sunday, May 10, 2009 12:26 AM
Subject: Re: [RFI] Alarm Systems and EMI/EMC


> Jim Brown wrote:
>
>>On Sat, 09 May 2009 12:28:05 -0700, Michael Tope wrote:
>>
>>
>>
>>>Anyone know any home security equipment dealers who are hams or who
>>>know anything about EMI/EMC?
>>>
>>>
>>
>>No experience with these guys, but security systems are notorious
>>for RFI susceptibility.  FWIW -- that 300 MHz range is commonly used
>>for garage doors and remote control of A/V systems. I don't know of
>>instances of RFI to the RF functions, but expect problems with  RFI
>>to other circuitry. The usual fixes are twisted pair wiring, caps
>>across wiring from dry contacts, and chokes to kill common mode.
>>
>>73,
>>
>>Jim K9YC
>>
>>
>>
> Hi Jim,
>
> The feedback I am getting suggests the wireless systems are superior to
> the wired systems in terms of EMI-EMC. This is not surprising since your
> are getting rid of long lengths of twisted pair wires when you go with a
> wireless sensor system. I don't need to tell you that it is those wires
> where the trouble often comes from.
>
> 73, Mike W4EF.................
>
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