On 7/17/2021 5:19 PM, Don Y wrote: > On 7/17/2021 6:07 AM, ABLE1 wrote: >> Hello, I find this VERY interesting. I won't go into the whole story >> since it is very long but I have a customer that has an alarm system >> that I installed. It has wireless sensors for doors and such. >> There has been a few times that the system does not receive signals >> from the transmitters for periods of time from 45 minutes to 2 days. >
2 *days*? Are you sure someone isn't (illegally) operating > a transmitter, nearby? >
That is a possibility. Again finding and proving is the challenge.
> During this time their garage door opener remote does not work unless >> you hold it in you hand reach up to within 18" of the opener antenna >> and then it will work. >>
>> During that time the problem or source can't be determined. >> In discussions with neighbors it has be determined that at least >> 4 others, next door and across the street have experienced the same >> with there openers. >>
>> Then it all stops and goes back to normal operation??? >>
>> This happened about 2 years ago and then again about a month ago. >> That I know about that is. >>
>> Needless to say when it IS NOT happening it is absolutely impossible >> to find. When it IS happening it is absolutely impossible to find. >>
>> The openers have a red LED on the unit that is used for learning in >> a remote button. Normally it is off until it receives a signal from >> a remote to open. During these events the LED is solid red for the >> entire time frame. Then during the end of the event it starts to >> flicker and then off. >
> Verify the *complete* behavior of the indicator. Usually, when > in "learn mode" (activated by a button on the RECEIVER), the > indicator will flash (until it times out). >
> Some flash when they detect an obstacle in the path of the door > (either photoelectrically or by sensing an increased current > draw by the motor) >
> Does "lit" coincide with the *entire* open/close cycle? I.e., > the behavior you are seeing SHOULD be accompanied by the door > moving (?) >
This LED is primary for learning in a remote. And just blinks when the remote is pushed. Which is seeing the RF Signal. Normally the LED is off. During my observation at the 45 minute period. The handheld remote would not work unless it was held up within 18" of the antenna. Also the Subaru header button did not work. There were two house doors that would not communicate the doors were open or closed to the security panel during this time. At the same time the next door neighbor's garage remote would not work. Then the LED started to blink and then off. Door contacts then worked as they should. The event was over and as I am aware has not returned.
> The security devices are on 319.5 Mhz and the door opener is on 318 Mhz. >>
>> Is there any thoughts here as to what other than Military Radar that >> could be causing this issue with such intensity in a small area?? >
> Almost anything can be an "unintentional radiator" -- even things like > christmas lights! >
> I'd wonder if someone wasn't (naively) putting a bunch of hash out. > The "45 minutes" sounds like someone might be "doing something" > (or USING something) for a short period. The "2 days" suggests it > got left *on*! I agree, but when it is not on it can't be found.
I lived in a house with the garage located beneath the master bedroom. > Vacuuming the carpet in the MBR would often result in the garage door > opening. We'd come out, the next morning, to leave for work and > wonder which of us had "*left* the door open"! (Ans: neither) >
>> There is a local airport with control tower about 2 miles away. >
> Possible. Why not go sniffing for signals? TV or radio stations > nearby? No Radio or TV nearby. Closest TV station is 6 miles as the crow flies. But I would think that if something that far away would have a much broader area effected rather than this very small area of maybe 6 homes. At least that I know about at this time.
It would make more sense that what ever it is would be located in one of the nearby houses that is radiating out 306 degrees, but What?? And Where??
>> I say a small area (200' square box maybe??) but it could be effecting >> a larger area but I have no way to know or to find out without having >> a town meeting. >>
>> Any thoughts on the subject would be most helpful. >
> When the problem next manifests, try to shield the affected unit. > This would at least give you an idea if the interference was radiated > or conducted. In most places, several homes are fed from a single > transformer. So, your line is a direct reflection of what's happening > in your neighbor's homes. Neighbors served by *another* transformer > will have two transformers acting to attenuate signals between your > home and theirs. >
> [Here, it's 4 homes per xformer -- and I can easily deduce which homes are > serviced "together" (or service is all below grade)] This a new 55 and over community that was new in the past 3 years or so. Houses are rather close and streets are narrow. As things always seem to go it was first thought that the new security system that I was installing was the cause of the problem with the Door Opener.........
I have more time in this problem trying to find the source or just pondering the problem than I want to think about. Total LO$$!!
It is horrible when you can't measure it, see it, touch it, taste it or even smell it!!!
BTW I may have forgotten to mention that there are two Door Openers in this house and both react exactly the same way.
From what I gather at this time is that it may be one of the following.
Military Radar RF Newbie building a new toy TV tower sending out a bad signal Christmas lights turned on during the spring/summer Old bad Florescent Light Ballast producing bad RF Electronic Music Box with no FCC approvals turned on infrequently Something else that I can fathom!!!
Question: How would I "shield the affected unit" as suggested?? Tin Foil around the opener?? Tin Foil over the wireless door transmitter?? Place a metal box over the antenna on the security receiver??
How is that going to determine if the interference was radiated or conducted??
Thanks for any input!!
Les