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Re: [RFI] Smoke-alarm Interference - not TVI but SAI

To: rfi@contesting.com
Subject: Re: [RFI] Smoke-alarm Interference - not TVI but SAI
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 22 Oct 2014 10:26:15 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 10/22/2014 7:47 AM, Mike Ryan wrote:
ANY amount of HF rf would set it off.

The alarm industry is notorious for ignoring RF susceptibility. When the RF is coupling via wiring from dry contacts in the form of a simple on/off, a cap across the input of the receiver will generally fix it. If the interconnect is sending data, a cap will likely kill the data. Mfrs often tell their users to use parallel conductor wiring for interconnects, which makes them more susceptible to differential mode RFI. They SHOULD be using good twisted pair, which strongly rejects differential mode coupling.

73, Jim K9YC
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