I have an older wired alarm system that uses serial data, and it is indeed awful. The serial data is quite slow but it has no filtering. I added an LC filter that works well enough to keep the RFI out of my station, at least down to the level of what comes from my neighbors and keeps my station from setting off the alarm system (most of the time).
At my son's house, he and neighbors have some SimpliSafe and other wireless alarm systems and the HF Ham bands are wiped out by the RFI. I have no idea what nominal frequency range or signalling they use. I would expect for battery life they would not transmit often, but whatever they do to create the RFI is continuous. I also have a hard wired smoke alarm from Kidde. That uses a DC interconnect between units. I believe any unit that goes off pulls a line up to about 9 V and they all go off. They are kind of cagey as to exactly what the interconnect signal is though, so I may be a little off. I have not detected any issues with RFI or susceptibility. Those may indeed work for you. I do have a Spectrum Analyzer and multiple types of clamp on probes and antennas but have not taken the time to do any quantitative measurements of any of these. Having to tell the Fire Department that the fire alarm is false is not a good thing. 73, Mark W7MLG On Sat, Oct 24, 2020 at 7:38 PM Jim Brown <j...@audiosystemsgroup.com> wrote: > > On 10/24/2020 6:53 PM, Harlan Sherriff via Elecraft wrote: > > So, guess I’ll send these back and get some hardwired interconnected units. > > That is probably a recipe for noise, radiated by that interconnected > wiring. The security industry has long been notorious for EMC to and > from their systems. WiFi interfacing should reduce both significantly, > but before committing to anything, chat up engineers at the company > about RFI. > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to marklgoldb...@gmail.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
