I would expect that if it was getting into an alarm system, the alarm would fail in some way. I had a bad problem with mine, cured by a 5th order 200 kHz lowpass filter where simple ferrites and caps did not work. The alarm system has low frequency digital data. I built it with some caps and a few turns on mix 31 cores I had. Since it is not a 50 ohm system, the filter is not exactly as designed, but it worked well enough to completely eliminate the problem. I put it at the alarm controller that was getting affected.
73, Mark W7MLG On Feb 23, 2016 2:04 PM, "paulb" <xtr348...@xtra.co.nz> wrote: > > Hello again folks > > Thanks to all for the suggestions and hints to what this problem could be. > > Tests have been done at 2 locations; my own home station and here at > another > property ( work in progress as we > politely say..) about 125km south of Auckland. > > The same second harmonic garbage is heard at both places. Over the last day > I have completely swapped out > all the 80m and 40m antenna and feeder components here in the provinces. No > change. > > What I now strongly suspect is the only common point at both locales; > > both properties have burglar alarms installed. Both are almost identical > well known European name brand units. > There is no detectable RF radiation from the processors or wiring. > The clincher now that I think about the last time we ran 2 stations here > without any drama > was before the alarm was commissioned here. > > I have dropped the supply and backup DC to the alarm here without any > change, > Likely 3.5 meg RF is simply hammering the PIR's, cable runs are in the roof > cavity. > Can't %100 prove this without fairly major re-wiring, will leave it as is > for the meantime, > > thanks again guys > > cheers from ZL > > Paul > zl1ajy > > > > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Slighty-off-topic-80-meter-second-harmnic-how-to-stop-tp7614506p7614534.html > Sent from the Elecraft mailing list archive at Nabble.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 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
