[RFI] ADT security system noisy?

[Jim Brown]

On 2/16/2026 12:49 PM, David Eckhardt wrote:
> I'm sure there is lots of digital circuitry within the box.  Digital
> circuitry = RFI ! ! !  I'd suggest temporily disconnecting the battery.
> Let ADT know before you do so or they may interpret that as in ingress.
> Also disconnect their dable, if any.  I'll be with those two actions, the
> RFI will cease.
> 
> Have you "sniffed" the ADT box and installation with a spectrum analyzer
> and a small (maybe 5-cm in diameter or so) loop?

Or probe it with a battery operated receiver, like one of those noted in 
my RFI tutorial. http://k9yc.com/KillingRXNoiseVisalia.pdf  Some vintage 
VHF FM talkies have wideband receive and AM detectors. They make good 
probes. The lowest cost Tecsun PL380 (about $50) also has wideband 
receive. I suggest that you do this before contacting the security company.

73, Jim K9YC