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  1. #1
    Automated Home Guru
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    Default RF interference ?

    Interesting one yesterday, I was walking past my alarm control panel and it had a red light on and was saying 'Jamming', I cleared it down a couple of times and then didn't think too much of it. I then went to adjust a setting on the EvoHome controller and found that it had lost connection to every device. Most devices had the red triangle lost connection icon and some just had the egg timer icon on them.

    After a while, maybe within the hour, it had all sorted itself out again. Only thing I can think of was that there had been a large car accident up the road from us and there were multiple emergency services vehicles at it.

  2. #2
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    Sure sounds like RF interference - the chances of your alarm and Evohome both totally losing communication at the same time for any other reason is pretty remote.

    How long were the emergency vehicles there ? Evohome won't report any comms errors until quite some time after comms is lost depending on the device type.

    For continuously lost comms an HR92 will go into "Sync" mode after about 30 minutes but the panel wont show an error for nearly an hour, a BDR91 will show a red error after about an hour, and the hot water sensor wont be reported as faulty for nearly 3 hours...

    How far up the road was the accident ?

  3. #3
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    Hmm. I am not so sure. You do not say how far away the accident was. Most household devices using RF at VHF and UHF frequencies do so at low power and similarly the emergency services for if they used high power they would fry their brains. Also they are all on a different frequency to Evohome. Not though impossible to suffer a problem. Put simply a transmission on 450mHz can interfere in the 900mHz band. My initial reaction is your problem is not the emergency services. But then, the emergency services may have actively jammed.

  4. #4
    Automated Home Legend paulockenden's Avatar
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    Default

    More likely to be a neighbour using 868mhz wireless speakers or headphones. Something that streams audio or video, rather than a 'data' type application.

  5. #5
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    Quote Originally Posted by G4RHL View Post
    Hmm. I am not so sure. You do not say how far away the accident was. Most household devices using RF at VHF and UHF frequencies do so at low power and similarly the emergency services for if they used high power they would fry their brains. Also they are all on a different frequency to Evohome. Not though impossible to suffer a problem. Put simply a transmission on 450mHz can interfere in the 900mHz band. My initial reaction is your problem is not the emergency services. But then, the emergency services may have actively jammed.
    In my reply I agreed that it's almost certainly interference, but I was a bit skeptical that it would be the emergency services incidence - hence asking how far away they were and how long they were.

    For every single zone in evohome to be reporting comms errors the interference would have to be there for a good solid hour or more.

  6. #6
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    I just measured it out on google maps, they'd be about 450m away from the house. House alarm reports:

    RF Jamming: 15:37
    RF Jamming Restore: 15:39
    RF Jamming: 16:23
    RF Jamming Restore: 16:59

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