What can I do about local interference that wipes out both N wavebands?

Discussion in 'Home Networking' started by tim, Jul 18, 2011.

  1. tim

    tim Guest

    I had impeccable wireless performance for years in this house - and
    then, 3 months ago, something turned up in the vicinity that regularly
    takes me offline completely. I bought a better 2.4GHz wireless N-
    Router (Billion), then hung a 5GHz AP off it, thinking the
    interference would be restricted to that frequency(ish). But no: In
    the evenings, in particular, someone turns something on... and I can
    lose sight of both router and AP. This is not another 802.11x
    network. It doesn't make any difference what channel the comms are on
    - it wipes it out completely.

    I leafleted all the local houses a couple of months back, but no-one
    owned up to anything - so, the question is: What can I do next? Does
    anyone offer diagnosis of the source as a service? I'd glafly pay,
    it's driving me to despair...
    tim, Jul 18, 2011
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  2. bless, I'd pay the gladfly too ...
    Victor Meldrew, Jul 18, 2011
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  3. It maybe not a reception problem. I had similar symptoms and found the cause
    was that the DG834Gv2's AP wireless would shut down when the router was
    located too close to a DECT cordless phone base station.
    Anthony R. Gold, Jul 18, 2011
  4. How well do you know your neighbours? In your situation I'd ask a couple of
    houses each direction to see if they have the same problem. It may turn out
    that it is something localised to your house, or maybe your house and one
    each side, which would suggest it is something in your house that is doing
    the damage. Or it may be that your neighbour to the left has no problem,
    but all your neighbours to the right do. It'd let you determine the
    direction of the source if it's small and local.

    Maybe ofcom, or whoever deals with illegal broadcasts could be convinced to
    get involved if it's covering a fairly large area.
    Simon Finnigan, Jul 19, 2011
  5. tim

    Rob Morley Guest

    Someone nearby installed homeplug Ethernet-over-powerline crappy
    networking gear? It's a notorious cause of wideband interference that
    many users don't even associate with wireless communication because it
    runs over the mains circuits, and that Ofcom seems unwilling to do
    anything about. You might be able to track down the source by
    wandering up and down the street with a laptop, or even an AM radio.
    Rob Morley, Jul 19, 2011
  6. You mean the mains adaptors that make it nice and easy to get signals
    through thick Walls and so on - hardly crappy by any reasonable definition.
    Also nothing to do with wifi interference, I know many people who use both
    in the same house with no problems at all.
    Simon Finnigan, Jul 19, 2011
  7. tim

    Rob Morley Guest

    Some common implementations fail by a wide margin to meet RFI emissions
    standards, and are known to cause problems with radio equipment
    including Wi-Fi. So crappy by a "we've only got one electromagnetic
    spectrum so don't be antisocial with it" definition.
    Rob Morley, Jul 19, 2011
  8. Isn't there an argument that the occasional amateur radio bod who wants to
    stop everyone using mains networking is the anti-social one?
    Simon Finnigan, Jul 19, 2011
  9. tim

    Rob Morley Guest

    On 19 Jul 2011 19:42:22 GMT
    I'm sure there is, but views on how a good society should function will
    Rob Morley, Jul 20, 2011
  10. Is your internet connection to the house wireless or does it use some
    form of wired feed, like DSL, ADSL, Cable, or Fiber?

    If your feed is a wired one try hooking a PC directly to the feed (no
    router) and see if it continues to function properly. Possibly
    something is totally hosing your inbound feed resulting in a overloading
    of the router.

    As for problems with the neighbors, or even with in your house, I have
    had a problem which would take out all wireless connections. It took a
    week of trying to track the signal along with power company people once
    we convinced them that the signal was showing up on our power feed.

    That problem was tracked down to a defective thermostat control in a
    neighbors water heater. The relay was arcing badly as well as cycling
    on/off rapidly, but only under full load, as when they came home for the
    night and took showers and ran the dish washer. The arching was not
    enough to cause the circuit breaker to trip. Once the relay was
    replaced the problems were gone.

    Another thing worth trying is the freeware program called inSSIDer 2
    which can be found at:


    It can be used to view wireless signals in your local area and with luck
    the interference as well. It inSSIDer shows the interferrendce try
    turning off the mains breaker at your place and see if the interference
    is still covering the "N" band. If the signal goes away when the mains
    are off then most likely the problem is inside your home. Then it is
    time to power individual breakers on/off until the problem feed/device
    is identified. Installed on a laptop you can use inSSIDer to walk
    around to try and narrow down the area of the interferrence. If your
    laptop radio supports an external antenna you could plug in one of those
    cheap directional antennas and use it along with inSSIDer to track down
    the source of the signal. With a little added aluminum foil shielding
    you could restrict the range of your laptop to try and narrow down the
    source if your laptop does not support an external antenna, just don't
    block the cooling vents.

    The Metageek site also has some commercial programs/devices like the
    WiSpy series of products you could purchase which plug into a laptop to
    turn it into a spectrum analyzer which also could be used to track down
    the offending signal.
    GlowingBlueMist, Jul 20, 2011
  11. Exactly - why should the tiny number of people wanting to use an old
    analogue technology, that is inefficient in it's use of the radio spectrum,
    stop a much larger group of people using a different technology? Why is
    your wish to use your radio set more important than me and my 5 neighbours
    wanting to network their houses well without drilling holes and running
    cables everywhere?
    Simon Finnigan, Jul 20, 2011
  12. tim

    Daniel James Guest

    It's not an easily defensible argument, if there is ... unless the
    activities of the radio bod somehow interfere with his neighbours'
    "quiet enjoyment" of their property.

    Assuming that the radio bod causes no unpleasant emissions (apart from
    his use of the radio bands prescribed for his use and those of his
    fellow radio bods) he is doing no harm to others. If the user of a
    mains networking device causes EM radiation that interferes with the
    reception of said bods' radio devices then they are causing a nuisance
    ... and the fact that there may be more of them than of the radio bods
    is immaterial.

    I doubt that a court would hold that the networkers were doing anything
    unreasonable, though, so the radio bod probably has no legal recourse
    ... unless he can show that the networking kit that is giving him
    trouble fails to meet some legal regulation, in which case the
    networkers might be told to upgrade their kit so as to meet the regs.
    (which might or might not prevent it from interfering with the radio).

    Not a lawyer, just sayin'.

    Daniel James, Jul 21, 2011
  13. I don't recall "radio bod" (a/k/a Conor) implying that users of Homeplug
    powerline networking were doing anything wrong. His gripe was over the
    distributor's claim of CE certification. He believed the equipment was not
    properly tested and it did not meet the EMI technical standards required.
    Anthony R. Gold, Jul 21, 2011
  14. By forcing people to use wifi rather than mains networking, they are
    forcing others to change the way they want to do something. the neighbours
    may want other devices to use the spectrum normally used for wifi, may have
    thick Walls that stop the signal etc. Mains networking makes some things
    much easier, at the cost of a very small hobby being inconvenienced. Given
    that it's been decided acceptable to stop all non-digital capable TV's
    being used without extra equipment this seems a small additional burden on
    those who like analogue technology :)
    The extension of that point is that a single person wanting to listen to
    radio signals in the wifi spectrum should be able to stop everyone else
    using wifi equipment, which seems ridiculous.
    Simon Finnigan, Jul 21, 2011
  15. tim

    Daniel James Guest

    I think perhaps you're missing my more general point ...

    What I was suggesting was that if two (groups of) people each want to
    do something, and one thing interferes with what other people (not
    necessarily limited to members of the other group) want to do, while
    the other does not, then one's sympathies should generally be with the
    group that wants to do the thing that doesn't cause any interference.

    (I mean interference in a general sense, here, not specifically
    electromagnetic interference.)

    So if, say, Alice wants to light a bonfire in her garden to burn dead
    leaves and her neighbour Bob wants to hang his washing out (while one
    would hope that they might come to some mutually convenient
    arrangement) I think most reasonable people would say that Bob hurts
    nobody by hanging out his washing to dry, but that by lighting her
    bonfire Alice would risk dirtying Bob's clean laundry -- so one would
    say that Bob's wishes should prevail.

    I don't think anyone would say "That Bob is being unreasonable by
    washing his smalls, he's stopping Alice from having a bonfire!".

    Note that the smoke from Alice's fire might also inconvenience Carol,
    down the road, who wishes to sunbathe in her garden, and Dave next door
    who wants to photograph the lunar eclipse that afternoon ... neither of
    these people is inconvenienced by Bob's hanging out his washing.

    One might also note that Eddie the Environmentalist would say that
    Alice shouldn't burn her leaves at all, because that will release CO2
    into the atmosphere, and the leaves could be composted.

    So, back to your point: Nobody if forcing anyone to use WiFi. The
    suggestion in an earlier post was that HomePlug-type networking over
    the mains in one house, or between neighbouring houses, might in some
    way affect the ability of the occupant of another house to use some
    sort of radio equipment (what sort doesn't matter, but the OP was
    talking about WiFi).

    I don't know whether that is likely to be what's really happening. I
    don't know whether that's something that only happens if the mains
    networking kit is faulty or out-of-spec. I do know that mains noise
    (from sources other than networking kit) is a major problem for devices
    that implement networking over the mains, so I'm sure the manufacturers
    are sensitive to the issues. I do know that there's an IEEE spec for
    networking devices, that sets down standards for the power,
    frequencies, etc., that such devices can use. I do know that the
    HomePlug Alliance have a certification programme that attempts to
    ensure that such devices operate within spec. I'm pretty sure there are
    regulations that are supposed to prevent any mains electricity
    subscriber from (ab)using the supply in any way that might affect the
    quality of service to other customers ... but I can't find any
    reference to them with a quick Google ...

    But supposing that is what's happening ... suppose Alice, having been
    persuaded by Eddie to buy a composter, turns on her PC and HomePlug
    network and this in some way causes interference on Bob's radio. That's
    unfortunate, but my sympathies are still with Bob ... just as they
    would be if it had been Alice's WiFi that prevented Bob listening to
    the Proms as he did his ironing, or her Microwave, or her cat's
    automatic cat-flap-opening collar. The point is that Alice has some
    piece of kit that is actively upsetting some kit of Bob's. Bob's radio
    (I'm assuming) doesn't stop Alice's PC from working, doesn't slow down
    her ADSL connection, doesn't make her toaster make toast that's darker
    on one side than the other, doesn't make her hairdryer suck rather than
    blow ... the only interaction between all these devices is that Alice's
    HomePlug screws up Bob's radio.

    If I were Bob I'd be pretty pissed off, and I'd want to know what I
    could do about it. If it turned out that Alice had a cheapo knock-off
    HomePlug clone from a nameless far-eastern vendor who hadn't
    implemented noise suppression then I think Bob would be well within his
    rights to suggest that Alice bin it and buy one that wouldn't
    Yes, sure ... but that doesn't mean that anyone has any /right/ to use
    it. We all have to get along in this world, and if that means Alice has
    to get a better HomePlug device -- to run a bit of CAT-5 down her
    stairwell -- in order to let Bob enjoy the Proms in peace so be it.

    I'm sure I could get rid of the Jehovah's Witnesses a lot more quickly
    when they come knocking on the door if I belaboured them with a stout
    stick ... but instead I explain politely that we're all Pastafarians
    and they'll probably have more joy with the Sikh family next door, and
    away they go until the next time.
    That's taking my point a bit further than reason allows. The WiFi
    spectrum has been set aside for WiFi, so anyone trying to use it for
    anything else is on dodgy ground. If your WiFi kit causes interference
    outside the WiFi spectrum then it's probably crap kit and, yes, I
    should be able to stop you using it -- but that doesn't stop you using
    WiFi, it just means you have to get some new kit that doesn't

    I don't think that's unreasonable at all.

    Of course, if my radio/TV/whatever is so crap as to pick up your WiFi
    signal as well as the channel it's supposed to be tuned to then that's
    my problem. Finding out whose kit it is that's crap isn't easy!

    Daniel James, Jul 22, 2011
  16. 802.11 technology is designed for use in a shared spectrum and must coexist
    with services such as BlueTooth, cordless phones and microwave ovens, etc.
    Anthony R. Gold, Jul 22, 2011
  17. tim

    Rob Morley Guest

    Thanks for taking the time to explain, something which I couldn't be
    bothered to do because it seems blindingly obvious to me and I hesitate
    to engage with people who don't "get it" on the basis that they're
    likely to be either thick or people with whom I'm unlikely to ever
    Rob Morley, Jul 22, 2011
  18. tim

    Daniel James Guest

    I thought, when I started, that I was going to be able to write a
    succinct response of a paragraph or two ... <smile>.

    Anyhow, you're welcome!

    Daniel James, Jul 23, 2011
  19. tim

    Daniel James Guest

    You're right ... the frequency range is set aside for WiFi *and*
    certain other technologies.

    There's not much we can do about microwave ovens as 2.45GHz corresponds
    to the energy of the most convenient vibrational mode of the water
    molecule for ovens to excite with microwaves -- at least the ovens are
    designed not to leak radiation!

    As you say, though, these things are -- must be -- designed to coexist.

    To paraphrase an old adage: "be conservative in what you emit and
    forgiving of what you receive".

    Daniel James, Jul 23, 2011
  20. I get that you have a hobby, what I don't get is the refusal to accept that
    other people have a right to use the EM spectrum as well. A very niche
    hobby shouldn't take priority over the convenience of a large group of
    people IMHO.
    Simon Finnigan, Jul 23, 2011
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