Toastman - Suddendly Wifi disconnections

Discussion in 'Tomato Firmware' started by RixNox, Jul 28, 2013.

  1. RixNox

    RixNox Serious Server Member

    I' am happily running Tomato Firmware v1.28.7501 MIPSR2Toastman-RT K26 USB VPN on my Asus RT-N16 since months.
    All of a sudden I got Wifi disconnections although sitting close to the router.
    Checking out the router status, I have discovered that Tomato is issueing some interference problems (floating from acceptable to severe)
    I thought some cordelss in my house was interfering with the router, however when turned off the same interference level was reached.
    InSSIder shows no other network other than mine (country side):

    MAC Address    10:BF:48:E6:37:9E
    Wireless Mode    Access Point
    Wireless Network Mode    Auto
    Interface Status    Up (LAN)
    Radio    Enabled
    SSID    Casanova
    Broadcast    Enabled
    Security    WPA Personal (PSK) + TKIP / AES
    Channel    4 - 2.427 GHz
    Channel Width    40 MHz
    Interference Level    (ranging from Acceptable to Severe)
    Rate    (ranging from 1 to 300 Mbps, however mostly to 95) 
    Now I thought my Internet receiver/transmitter (Mikrotik Routerboard) sitting on my house's roof, may be interfering with the the modem:
    MikroTik RB/711A-5Hn-M Wireless 802.11N/A CPE
    CPU    Atheros AR7240 400MHz network processor
    Memory    32MB DDR SDRAM onboard memory
    Boot loader    RouterBOOT
    Data storage    64MB onboard NAND memory chip
    Ethernet    One 10/100 Mbit/s Fast Ethernet port with Auto-MDI/X
    miniPCI    none
    Wireless    Built in 5GHz AR9280 802.11a/n card,
    1 MMCX connector
    Extras    Reset switch, Beeper
    Serial port    none
    LEDs    Power, NAND activity, 5 user LEDs
    Power options    Power over Ethernet: 10..28V DC (except power over datalines). No power jack
    Dimensions    10.5 cm x 10.5 cm (4.13 in x 4.13 in) Weight: 67g
    Power consumption    Up to 4.5W at 18V full load (0.245A)
    Operating System    MikroTik RouterOS v4, Level3 license
    RX sensitivity    802.11a: ?92 dBm @ 6Mbps to -76 dBm @ 54 Mbps
    802.11n: ?92 dBm @ MCS0 to ?73 dBm @ MCS7
    TX power    802.11a: 23dBm @ 6Mbps to 19dBm @ 54 Mbps
    802.11n: 22dBm @ MCS0 to 15dBm @ MCS7
    Modulations    OFDM: BPSK, QPSK, 16 QAM, 64QAM
    However the Mikrotik transmitter seems using 5GHz band.....

    I have started thinking about solar flares......

    What do you think? Any idea?
  2. Marcel Tunks

    Marcel Tunks Networkin' Nut Member

    Try channel 11 if you're getting interference on 4.

    Change channel width to 20MHz.

    If your wireless devices are frequently close to the router, then turn the transmit power down.

    Does your cordless use 2.4GHz? If so, you'd need all the handsets and the base to be off (i.e. battery pulled or fully drained) to ensure that they aren't the cause.
  3. RixNox

    RixNox Serious Server Member

    Of course I have turned off the handsets and the base (unplugged from power)
  4. Marcel Tunks

    Marcel Tunks Networkin' Nut Member

    Didn't mean any offense. Don't know if any cordless phones go into low power state & continue transmitting rather than truly shutting down when shut off. None of the ones I've owned even had a power button. Seemed like battery pull was a way to be sure.
  5. RixNox

    RixNox Serious Server Member

    No problem Marcel :)
  6. Monk E. Boy

    Monk E. Boy Network Guru Member

    As a general rule you should use channels 1, 6, and 11 for 2.4Ghz and only those channels. Because 4 sits between 1 and 6 it receives interference from both 1 and 6 (as well as causes interference on both).

    Unfortunately 2.4Ghz cordless handsets are a pain in the derriere to deal with since they assume nothing else will be using 2.4Ghz. If you're in a multi-tenant building (condos, apartments, townhouses, etc.) then you could be receiving interference from a neighbor, or even their 2.4Ghz cordless phone. 2.4Ghz is barely slowed down by brick/cinderblock walls, much less the typical drywall w/insulation found in multi-tenant buildings. Cordless handsets will change "channels" faster than you can blink and often, confusingly, will change to the worst possible frequency range that's guaranteed to cause WiFi interference.

    Sometimes though the interference is just a phantom caused by bugs in Broadcom's (closed source) driver. Not much you can do in those instances besides disabling the wireless device and enabling it, or changing to a different channel (both will quit/reload the driver).
  7. RixNox

    RixNox Serious Server Member

    The house where to modem lies is a country side house. Very thick rock walls. First neighbor in 800mt.
    3 cordless sets one for each floor.
    On top of the roof, the Internet transmitter/receiver in the 5Ghz realm.

    How do I change the modem's channel?
  8. Inkrypted

    Inkrypted Serious Server Member

    I think he was referring to the channel the router uses. In the Configuration page under Basic and Network change Channel from Auto to a set channel such as 1 thru 6. Also are you using Bluetooth devices such as Game controllers, headsets,etc? If so changing the Bluetooth Coexistence to Preemption under Advanced and Wireless in the Tomato configuration page can help.
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