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[RFI] Re: alarm system RFI

To: <rfi@contesting.com>
Subject: [RFI] Re: alarm system RFI
From: n4zr@contesting.com (Pete Smith)
Date: Thu, 07 Nov 2002 01:47:33 -0500
At 10:00 PM 11/6/02 -0500, WB2JUF wrote:
>But here's the kicker - the most intense levels of the RFI (like a loud
>buzzsaw) are coming from - my rain gutters!!

For what it's worth department... I experience occasional mild RFI from the 
IR sensors on my garage doors.  When sniffing with a portable HF receiver, 
I found the loudest noise was coming from the tracks that the doors move 
on.  It wasn't very loud really, so I didn't do anything about it, but I 
wonder if grounding the rails would have helped, and if something similar 
might help with your gutters.  Between the seamless gutter material and the 
pop rivets that are used to attach cormer sections and downspouts, 
conductivity might be fairly good for extended lengths.  Can't hurt to try, 
anyway.

I have noticed a similar phenomenon with line noise and other RFI on 
80.  If I bring my receiver close to my large 80m array, I can hear the 
noise re-radiated much more strongly than if I walk around the property 
away from the array trying to figure out what direction it's really coming 
from.

Another thought -- drop an e-mail note to W1RFI@arrl.org and ask Ed whether 
the ARRL might be willing to call or write NAPCO.  They ARE in violation of 
Part 15, there are probably lots of these systems out there, and a 
ringy-dingy from a large national organization might make a stronger 
impression than any individual ham.  This strikes me as somewhat similar to 
the wireless modem problem of a few years ago, where ARRL moved with 
dispatch to persuade the makers to make changes in their systems.

73, Pete N4ZR
Sometimes a tower is just a tower





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