[RFI] RFI To Intruder Alarm Systems

EP Swynar gswynar at durham.net
Tue Dec 5 06:37:37 EST 2006

Good Day All,

I wonder if anyone reading this might have personal experience(s) in the matter of suppressing RFI to intruder alarm systems...

We have a system here that employs a combination of motion detectors, and magnetically-coupled(?) "open window" detectors...my problem here occurs only on 80-meters.

When I transmit with about 100-watts, an alert button goes on in the contol panel, indicating that a re-set is in order --- when I run 200-watts, or more, the entire system goes off, just like a burglar had entered the house.

Note that this all occurs WITHOUT the system even being armed.

Obviously I have some line(s) in the system resonant on 3.5-MHz --- I've tried the usual winding of snap-on ferite chokes everywhere that I have access to (including the system's p.s.), all to no avail. I'm wondering if there's anything that I might do right at each sensor / motion detector to effect a cure...?

Any & all feedback would most certainly be appreciated...in as much as I have nothing whatever against QRP, I miss chasing DX at the bottom of the band on CW!

~73~ Eddy VE3CUI - VE3XZ

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