[RFI] RF into home alarm system

W5JR Mike w5jr.lists at gmail.com
Sun Oct 18 21:35:08 EDT 2015

As the subject line says. 

For the past two years, I've not caused any issue to our home alarm system. The typical 4 wire JK style wire run all over the house. Lots of doors and windows. And 13 smoke detectors. I run 1.5 kw, 160 to 10 (less on 30m) and nary a peep. 

Last eve, wanting to play a bit in the Pre-Stew on 160m, but as yet not having my 160 antenna repaired, I was able to get the tuner to find a match on the 80m OCF. Even with just 100w, folks were answering my CQ's. I'm sure there was lots of stray RF floating around. 

My wife came rushing over to the shack in a panic. It turned out the alarm was in full on,  every annunciator sounding simultaneously. Fire, intrusion - one big mess. I knew there wasn't a fire as the control panel told me there was a fault condition. Nothing on the control panel would clear it. Only by removing all power was I able to cleared it. 

Now that I've prepped you with the setup, the question is if anyone has had to tame their alarm system to reduce its RF susceptibility and what steps did you do to get there?

I don't expect the installer to have any useful input, nor the manufacturer, but they may have dealt with this for a neighbor to a ham. 

I'm anticipating the recommended solution will be lots of Mix 31. Can I wind all or several of the wires together on donuts? Am I better off using  one on each wire (yes, still multiple turns)? Would adding bypass caps be of any value? 

Mike / W5JR
Alpharetta GA

More information about the RFI mailing list