Wireless suddenly slow

Discussion in 'Networking' started by VirtualLarry, Nov 10, 2012.

  1. VirtualLarry

    VirtualLarry Lifer

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    I have FIOS 25/25 with TV, which gives me a 30/25 connection. Suddenly (today at some point), my speeds over wireless N have dropped from my full internet speed, to something around 1Mbit. This happens with both of my desktop PCs (running over WDS), and my laptop.

    Here's a speedtest from my wired HTPC.
    [​IMG]

    Edit: And here's one from my laptop.
    [​IMG]
     
  2. CubanlB

    CubanlB Senior member

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    Rebooted the WRT boxes that are running the WDS?

    New source of RF noise in the area?
     
  3. VirtualLarry

    VirtualLarry Lifer

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    I did reboot all of the three DD-WRT boxes. In fact, I shut down the two secondary WDS links entirely, in order to isolate the issue.

    I also tried swapping in a new power brick for my primary WDS router.

    I also went downstairs, and tried switching off a neighbor lady's router, that I recently installed for her. I did a speedtest in her apt, and get 30mbit/sec down (BEFORE I unplugged her router). Subsequent speedtests, even after unplugging her router, were down to 1-3Mbit.

    I'm afraid either my primary router is dying, or there is some new RF source.

    Maybe someone is cooking a thanksgiving turkey in the microwave? Seems kind of early for that. My connection never really faltered like this before.

    Edit: I have my primary Verizon FIOS router ahead of my primary WDS router. It is also Wireless N. I connect to it (on channel 11) and got a full-speed speedtest.

    So to isolate whether my primary WDS router was failing, or whether it was RF interference around channel 1, I changed the channel to 11.

    This is my new speedtest, from my laptop connected to my primary WDS router on channel 11.
    [​IMG]

    Pretty good.

    So what is generating so much RF that it is crapping up channel 1?

    Edit: Wireless "Rate" shown in DD-WRT status page is 72Mbit/sec. It should show 144Mbit/sec. So there might be noise coming into channel 11 as well, or perhaps just the presence of other routers on that channel.

    Edit: Now I'm not sure if it's my router or what. I swapped power bricks back to the old one, then I saw that the Rate on the primary WDS router went down to 5.5Mbit/sec.

    So I swapped the new one back in, but the Rate is fluctuating between 26, 39, 52, and 104.

    Here's a new speedtest from my WDS-connected desktop.
    [​IMG]

    Edit: Primary WDS router rate went to 5.5Mbit/sec again, Speedtest reflected that. Now it's at 104. It seems to bounce around a bit. Puzzling.

    Hmm, now I think that someone IS cooking a turkey in a microwave or something. Even changing the channel to 11, my primary WDS router is bouncing between 5.5 and 144. Just like a microwave cycling.

    Edit: Decided to pull out one of my spare DD-WRT routers, and set it up to replace my primary router. Finally got it all done and in place, and my Rate was still down to 5.5Mbit/sec at times.

    Figuring perhaps my Verizon router which was next to the primary WDS router was interfering, since they were both on channel 11, I decided to change the FIOS router to channel 6.

    Now my Rate is bouncing between 13, 39, 144, etc. But mostly stays up there.

    Perhaps "someone" is done cooking?

    Anyways, it's mostly back to normal now.

    Here's a speedtest of a WDS-connected desktop PC.
    [​IMG]
     
    #3 VirtualLarry, Nov 10, 2012
    Last edited: Nov 10, 2012
  4. CubanlB

    CubanlB Senior member

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    My experience with most N gear is less than stellar, but I am also extremely cheap so that may have colored my experiences some.

    How far apart are your WDS nodes?

    Other than getting a decent spectrum analyzer, trial and error may be your best bet to get the current system corrected. Positioning can make a world of difference. But not knowing what you are tryimg to avoid is a pita...

    Any way you can get wires ran and run the WRT units as just APs?
     
  5. VirtualLarry

    VirtualLarry Lifer

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    I guess it's not quite fixed.
    [​IMG]

    Really confused as to what could be causing such bad wifi performance. All of my gear is plugged into a UPS, could that be an issue? UPS going bad?

    Edit: And again, from the same PC, some time later on.
    [​IMG]

    It's so inconsistent.
     
    #5 VirtualLarry, Nov 12, 2012
    Last edited: Nov 12, 2012
  6. remixedcat

    remixedcat Member

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    what UPS do you have and how old is the battery? if you have an APC and the router is damaged they have a connected equipment replacement policy you may want to look into.

    Also have you reset your router? You've allready did the obvious such as changing channel, passwords, etc... so that didn't fix that....

    does this router work fine with another connection? Also have you tried a different modem?
     
  7. VirtualLarry

    VirtualLarry Lifer

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    I have FIOS, so I don't have a "modem".

    I get full speed always from the wired HTPC, so the actual internet connection is not a fault.

    When I check the router status of my primary WDS router (which is chained to the first Verizon router), it fluctuates between 5.5Mbit/sec up to 144Mbit/sec.

    I swapped out the router completely, including the power brick, with one of my new refurb spares. It's doing the same thing, so it's not the specific router that is the problem, I don't think.
     
  8. spidey07

    spidey07 No Lifer

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    Can you get a signal to noise ratio? That screams interference, especially the huge swing in data rates.
     
  9. VirtualLarry

    VirtualLarry Lifer

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    MAC Address Interface Description Signal Noise SNR Signal Quality
    xx:xx:xx:xx:yy:yy eth1 DD-WRT3 -38 -85 47 69%
    xx:xx:xx:xx:yy:zz eth1 DD-WRT2 -45 -85 40 60%

    This is what it gives me, for the other WDS nodes connected to it. They are in the other room, in opposite corners about.
     
  10. VirtualLarry

    VirtualLarry Lifer

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    I did recently upgrade my HTPC to an FM1 rig, in a new case with a new PSU. It's a 2.7Ghz quad-core A6-3670K. It sits on the same shelf with my routers and UPS.

    I went into the BIOS and did some deep searching, and by default, Spread Spectrium was disabled. I normally disable it anyways, but I tried enabling it this time. We'll see if it fixes the issue.

    I did try shutting the HTPC completely off, when my laptop was connected to the primary WDS router and showing a Rate of 5.5Mbit/sec. The Rate took quite a while to come back up, even after the PC was shut off, so I'm unconvinced that was the problem.
     
  11. bononos

    bononos Diamond Member

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    If you got an N class router it shouldn't be affected by microwave ovens right?
    Did you check to see who else is using channel 11 when the problem happens? inssider is a good free utility.
     
  12. spidey07

    spidey07 No Lifer

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    2.4 Ghz is still 2.4 Ghz and is affected by all the stuff in that spectrum. It's crowded as all get out by all kinds of things. It's getting to the point of useless. Baby monitors are the killer or anything else in the same spectrum, microwaves totally STOMP that frequency into the ground but normally only when they are running.
     
  13. VirtualLarry

    VirtualLarry Lifer

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    My Rate on primary WDS router was bouncing between 5.5 and 13Mbit/sec, on my wired desktop via WDS link.
    [​IMG]

    Edit: A few minutes later, when the Rate was showing 104, 114, 130, and 144.
    [​IMG]

    Edit: The next morning, at around 8am.
    [​IMG]
    Rate was locked at 5.5Mbit/sec for some reason.
     
    #13 VirtualLarry, Nov 12, 2012
    Last edited: Nov 13, 2012
  14. bononos

    bononos Diamond Member

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    Yeah but if its a dual band router the 5Ghz range is not as likely to be congested and will avoid the microwave oven inteference.
     
  15. VirtualLarry

    VirtualLarry Lifer

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    Hmm, I think I found another interesting data point. My other two secondary WDS routers DO NOT drop their transmit rate, in sync with the primary WDS router. They stay at around 117, and 144.

    If it is RF interference, it's only affecting the one room, and not the other.

    I still wonder if there is something about the HTPC I upgraded, but why wouldn't the transmit rate return to normal max values when I shut it down? So I don't think it's that.

    What are the odds that both power bricks, or both routers, have the same problem? Because I replaced the router and power brick entirely. I might just have to try doing that again.

    Edit: Ok, I tried swapping in a different, new power brick. One from a bunch I ordered off of ebay, brand-new from USA seller, that were 12V 1A replacements for my WNR834Bv2 routers. They match the adaptors with the WNR2000v2 routers (my current routers), except the adaptors shipped with those say "Efficiency: V", and the WNR834Bv2 adaptors say "Efficiency: IV".

    After swapping the adaptors, I'm still getting "TX Rate 5.5Mbit/sec" on my primary WDS router.

    So I decided to change the channel on all three routers to channel 1 again. Same deal.

    Routers 2 and 3 are at 107 and 144, but primary WDS router is at Rate 5.5 again.

    Why is it stuck in that transmit-rate ghetto? Is it overheating?

    Edit: Moved it out of that shelf, on top of the shelf next to my TV. Bounced up to 72, then back to 5.5.

    Edit: Discovered that changing the wireless channel to 1, N-only, and hitting "Save" and then "Reboot" didn't set them to channel 1. So I had to do that over again.

    It seems that S/N ratio is slightly better now.

    MAC Address Interface Description Signal Noise SNR Signal Quality
    xx:xx:xx:xx:yy:yy eth1 DD-WRT3 -30 -90 60 79%
    xx:xx:xx:xx:yy:yy eth1 DD-WRT2 -38 -90 52 69%

    Edit: It was locked at Rate 144Mbit/sec for a few minutes. Trying putting the router back in on the shelf, see if TX Rate goes down.

    WDS NodesMAC Address Interface Description Signal Noise SNR Signal Quality
    xx:xx:xx:xx:yy:yy eth1 DD-WRT3 -34 -83 49 74%
    xx:xx:xx:xx:yy:yy eth1 DD-WRT2 -42 -83 41 64%
     
    #15 VirtualLarry, Nov 13, 2012
    Last edited: Nov 13, 2012
  16. Charlie98

    Charlie98 Diamond Member

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    This is all very interesting, even if I don't know everything you are talking about/referencing. Just last night I was checking my buddy's system that I installed and his wireless is just about useless at this point. This gives me something to work with. Speedtest is a pretty handy utility.

    I checked my desktop and laptop, the scores were almost identical... far below what ATT is promising, but at least I know it's not my equipment.
     
  17. VirtualLarry

    VirtualLarry Lifer

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    Well, I have now switched from three WNR2000v2 units with DD-WRT, to three E2500 dual-band running Tomato build 104, running WDS on 5Ghz (channel 40), 40Mhz channels.

    I go to the "view devices", and I get around 45-50% signal rating on the two WDS nodes, but their TX/RX rates fluctuate between 300, 130, and then all the way down to 6. Very strange.

    What would be causing interference on BOTH the 2.4Ghz and the 5Ghz bands? Or do I have a power-quality problem that is affecting the power bricks of all three routers?

    Edit: I don't notice any lights flickering, and my UPS in my bedroom connected to my HTPC very rarely makes a "click" noise to briefly switch over to battery power.

    Edit: That page also says "Noise Floor: eth1 -60dBm" (2.4Ghz, 20Mhz, channel 1), "Noise Floor: eth2 -99dBm" (5.0Ghz, 40Mhz, upper, channel 40).

    Is -99dBm a good noise floor? I'm guessing that means no interference?

    Why does the TX/RX rate bounce so badly then?
     
    #17 VirtualLarry, Dec 16, 2012
    Last edited: Dec 16, 2012
  18. AnonymouseUser

    AnonymouseUser Diamond Member

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    You need to isolate the software/drivers. Boot a Linux LiveCD/USB (make sure wireless hardware is supported) and run some tests. If transfers are still poor then it's a hardware/interference problem, but if transfers are solid then it's a software/driver issue.

    I also recommend not using Speedtest.net to test your WLAN speeds. Transfer large files across the LAN for that, wireless to wired PC and back.
     
  19. VirtualLarry

    VirtualLarry Lifer

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    These are routers I'm talking about. I don't use wireless NICs.
    That was one of my next steps.