Is there a way to get WiFi NOISE levels for a mobile device?

Discussion in 'Wireless Internet' started by Paul B. Andersen, Jul 1, 2015.

  1. For *every* suggested app in this thread, I tried to download it for
    the iPad, and failed in all but one case.

    Unfortunately, while the iOS devices have a very clean user interface,
    they don't seem to allow the use of most of the powerful debugging
    tools that have been suggested by Jeff, a well known network expert.

    The iOS devices can use weak debugging tools like "Fing", but the
    best tool suggested, the SNR WiFi tool, I couldn't find for my iPad
    (nor even inSSIDer, nor WiFi Analyzer, nor Fritz!App WLAN, etc.).

    That's too bad because I had to do all my debugging with the Android
    phone, even though the iPads are part of our network. Even worse, my
    daughter and her friend have a mix of iPhones and iPads and Android,
    where, in their case, only my daughter's Android phone is capable of
    intelligent use of the suggested debugging tools.

    I don't know about what happens with jail-broken iOS devices, but, if
    your equipment is stock (as is mine), then I don't know *how* you can
    measure anything useful when the network is weak, as is the case in
    the described situation.

    Luckily, here in the USA, the network is very often very strong, so,
    it's less of a concern for us in the states than the kids in a
    foreign country (that doesn't even celebrate July 4th properly!). :)
     
    Paul B. Andersen, Jul 4, 2015
    #81
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  2. I don't memorize (or really understand) the 7 layers all that well, but,
    I do remember that the MAC address only goes from the mobile device to
    the router, and no further - so - I was very happy to see Jeff's simple
    characterization of my wired access point acting merely as a BRIDGE
    (which, I think, means the MAC also goes through it to the main router).

    So, that means TWO routers have my mobile device unique MAC address
    (if I understood Jeff correctly).

    The practical application of that knowledge is that I make sure to
    *change* my MAC address *before* connecting to any local hotspot that
    I don't own (e.g., Starbucks, McDonalds, the local library, etc.).

    You should too (IMHO).

    I don't have an iPhone, so someone here should suggest how to change
    the MAC address on the iPhone, because (I consider it) it is a key
    privacy bit in that it uniquely identifies *all* your communications
    if you're to repeatedly use a particular access point.

    In addition, it "can" be traced back to you personally, but, that
    would take a crime on your part for the tracking back to Apple's
    purchase records to be worth the trouble for an adversary.
     
    Paul B. Andersen, Jul 4, 2015
    #82
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  3. Yes. OSI Layer 2. As you note, fitting the layers of the todays
    TCP/IP networking into the OSI layer model is not a perfect fit.
    <https://www.google.com/search?q=osi+tcp/ip+layers&tbm=isch>
    OSI Layer 1 (physical) and Layer 2 (data link) are combined in TCP/IP
    as the network access layer. Since all 802.11 wireless is bridging or
    switching, I like to call it Layer 2 networking.
    Sorry, my mistake. IP is more accurate.

    What I'm trying to point out is that no IP addresses are involved in
    802.11 style wireless networking (except for device managment) and
    that everything in 802.11 wireless involves bridging or switching.
     
    Jeff Liebermann, Jul 4, 2015
    #83
  4. OOOOOps. Minor typo.

    My Linksys WRT54G is on channel 1 and the Netgear router is on
    channel 6 (based on your advice) where the WISP is on channel 11.

    http://i.imgur.com/js1MtBH.png

    This is all as per Jeff's advice from a few years ago when I
    first set the thing up (and when I was young and stupid) and
    before he stopped frequenting a.i.w in favor of the scientific
    repair groups (he likes geeks).

    Jeff's advice gives me the best separation allowed in the USA
    on the 2.4GHz channel that they all use.
     
    Paul B. Andersen, Jul 4, 2015
    #84
  5. The same or different channel is wrong. In infrastructure mode, the
    access point controls the channel, mode, protocol, encryption method,
    etc. The repeater and client radio can only follow the access point
    configuration. If for some reason, the access point wants to change
    channel, it can do so, and all the other boxes either follow or get
    disconnected via a timeout. That roughly what happens when you set
    the channel in the AP to "AUTO" (which methinks is a lousy idea).

    I would change the AP description to "controls the channel (and
    everything else)".
    Ummm... Wireless routers can only do infrastructure mode. If you
    configure the ad-hoc mode, it will disable the router section, and
    magically convert your wireless router into a wireless client. More
    bluntly, ad-hoc mode uses only client radios, that talk to each other,
    and do not involve any other networking devices. In order to talk to
    the internet or other network, they require a specialized gateway such
    as Windoze ICS (internet connection sharing).
    Gateway is normally applied to remote access devices, such as VPN
    routers, modem pools, and secure access servers. Comcast, in its
    infinite wisdom, has seen fit to rebadge all it myriad of
    modem/router/wireless/switch/phone/whatever conglomerations as
    gateways, probably because they lack the imagination to contrive a new
    name or understand the existing.

    A bridge is easy. I described it previously. A bridge has 2 ports,
    which do NOT need to use the same communications protocol. For
    example, cable and DSL modems are bridges. Only those packets, with
    destination MAC addresses that are across the bridge, will pass
    through the bridge. Packets without destination addresses, such as
    broadcasts, also go across the bridge. That's all there is.

    A switch is a bridge with more than 2 ports. Packets go only to those
    ports that have a devices with the destination MAC address. In other
    words, a packet only goes to the port with the correct destination
    address. This is good because no traffic goes to ports that are not
    involved in the immediate traffic. So, you could have major traffic
    between a machine being backed up, monopolizing two ports, without
    generating any traffic on the others. With a switch you can surf the
    internet while running a big backup or copying big files between
    machines.

    Mobile devices and phones have many ways in which they can be
    identified. As far as MAC addresses go, your phone can have multiple
    MAC addresses. Each defines a port, not a device. Best described by
    analogy. It's much like a house. You have a name (Your_Name or
    ), which lives at a physical address (house and street
    number or IP address). The house has many doors which can be used to
    pass "traffic" in and out. Those are the MAC addresses. Vendors can
    also assign their own identifiers to your house such as the cellular
    ESN, MEID, IMEI, etc, some of which may also need a MAC address to
    define which door into your device is being used. When you configure
    a wireless hotspot, you are building a bridge between two of these
    doors (WLAN and WIFI) each of which has a different MAC address on
    your phone. I've left out some obscurities and complexications, but
    this should cover the basics.

    Quiz tomorrow.
    Yep. It's difficult to complain about the weather when I live in
    paradise.
     
    Jeff Liebermann, Jul 4, 2015
    #85
  6. It's NOT at half speed when setup as an access point. The WRT54G can
    transmit and receive packets on both interfaces (ethernet and
    wireless) at the same time, thus eliminating the store and forward
    problem. It works at normal speeds, excatly the same as if it were a
    wireless router.

    However, if you installed DD-WRT firmware, and set it up as repeater,
    you would be stuck with the store and forward problem and run at half
    speed because the wireless interface cannot transmit and receive at
    the same time.

    Maybe this will help:
    ethernet <==> wireless No problem. Full speed.
    wireless <==> wireless store and forward, half speed.
    ethernet <==> ethernet usually full duplex, no problem.

    My experience with the WRT54G is that it's slower than a snail and
    can't handle cable modem speeds. I donated about 10 WRT54G routers to
    a group doing wireless mesh networks. I have about 15 more waiting
    for them to pickup. You might consider getting something more modern
    and faster. See the speeds at:
    <http://www.smallnetbuilder.com/tools/charts/router/view>
    The WRT54G isn't on the list, but I vaguely recall that it was less
    than 10 Mbit/sec (WAN -> LAN).
     
    Jeff Liebermann, Jul 4, 2015
    #86
  7. I don't recall either setup, so I won't offer an opinion.
    I'm surprised that you can do seamless roaming successfully. My stuff
    tends to lock onto an initial connection, no matter the signal level
    or SNR, and stay connected, even if I'm right next to a much stronger
    signal router, and the signal from the original router is weak. So, I
    use different SSID's and manually select which AP I want to connect.
    On a new system, I always try a single SSID first, but if it fails, I
    switch to different SSID's without hesitation.

    However, Ch1 and Ch2 are a bad idea. It should be on Ch1, Ch6, or
    Ch11. The problem is that the typical wi-fi signal is about 20 Mhz
    wide or 4 channels wide. Out of the available 11 channels, that give
    you about 3 channels that do NOT overlap. If your Netgear and Linksys
    devices can "see" each other, they're interfering with each other on
    Ch1 and Ch2. I suggest you move the Ch2 router to Ch11.
     
    Jeff Liebermann, Jul 4, 2015
    #87
  8. Paul B. Andersen

    Lewis Guest

    So stop posting to an iphone newsgroup.
     
    Lewis, Jul 4, 2015
    #88
  9. Paul B. Andersen

    Rod Speed Guest

    It gets a bit more complicated than that with my wifi extender
    which can be used both ways, and in a third way as well.

    It does use those names for the repeater and access point modes tho.

    The third mode is as a client which allows you to make say a printer
    which normally has just a Cat5 connection to operate wirelessly as well.
     
    Rod Speed, Jul 5, 2015
    #89
  10. Paul B. Andersen

    Rod Speed Guest

    There's nothing. One area where androids leave iOS for dead.

    iOS doesn't even show you the wifis that it decides aren't useable.
     
    Rod Speed, Jul 5, 2015
    #90
  11. Are you sure?
    My WRT54G is wired to an output port of my Netgear router, but,
    the WRT54G is on channel 3 while the Netgear router is on channel 1.

    So, while they have the same SSID, they clearly have different
    channels.

    In this screenshot below, my Netgear router (i.e., the main router)
    is the blue parabola while the WRT54G wired to it is the red parabola.
    http://i.imgur.com/js1MtBH.png

    They're clearly on different channels, but the WRT54G controls the
    channel "it" is on, not the Netgear router.
     
    Paul B. Andersen, Jul 5, 2015
    #91
  12. Well, I didn't want to get complicated - but I know exactly what you're
    talking about because I see it every day.

    The wife complained a lot about the iPad not switching over when her
    Android phone did just fine at her study at the far end of the house
    (where I placed the Linksys WRT54G repeater/extender).

    I finally told her to just turn off WiFi on the iPad and turn it back
    on, whenever she crosses the threshold into her study, and she's the
    type to just do it and not question why (because it works).

    So, in my experience, all the Android phones in the house have no
    problem switching to the wired access point of the same SSID as
    the main router, and all the iPads do have a problem.

    Easily enough solved; but I didn't want to bring it up as that
    complicates things (people always think that my particular set of
    iPads are faulty but they themselves haven't tested the things like
    I have and like I know you have as you've tested this stuff in
    detail as I have seen your web pages with the graphs).

    So, in summary, I kept that detail out because I was trying to
    simplify things.
    I keep making that typing mistake (dyslexia creeping in).
    Sorry.

    I have it set up *exactly* as you suggested, with channel 1 and channel
    6 and the WISP radio on channel 11 (where you can see bounceback here):
    http://i.imgur.com/js1MtBH.png
     
    Paul B. Andersen, Jul 5, 2015
    #92
  13. Thanks Jeff for clarifying, as I had followed your suggestions to the
    letter when I set it up, and I did remember that had I set up the
    spare WRT54G without wires, it would have been slower than with wires.
    That makes sense that the wireless NIC is the bottleneck. I don't
    think "my" version of the WRT54G (V6?) has enough memory to easily
    install DD-WRT anyway - so - the *only* way I can set up my Linksys
    WRT54G is by wire.

    That's a detail that I'm sure you knew; but for others, I put it out
    there that not all the routers have enough memory to change the
    operating system on them easily.
    That's a nice summary.
    I only now understood what you meant by the half speed (and I now realize
    it's due to the card itself having to do two jobs, versus the card
    sharing those two jobs with another card).
    It was a spare, so it was free.

    I also have a nanobeam M2, which I have to get around to setting
    up to extend the WiFi range out to the pool:
    http://dl.ubnt.com/guides/nanobeam/NanoBeam_M2-400_M5-400_QSG.pdf
     
    Paul B. Andersen, Jul 5, 2015
    #93
  14. Correction. The WRT54G is on channel 6, and it's wired to the
    Netgear which is on channel 1. (typo dyxlexia).

    I also have a nano which will beam by WiFi 15 miles, but it only
    has to make it to the pool. :)

    BTW, folks who are considering *buying* a $75 router to extend
    their signal should look at the specs on this $75 nano:
    http://dl.ubnt.com/guides/nanobeam/NanoBeam_M2-400_M5-400_QSG.pdf

    With two of those, and a clear line of sight, you can beam your
    WiFi to your brother ten miles away and it will be as if you're
    in the next room.

    The *only* thing I'd buy a router for is routing.
    For extending/repeating WiFi, I'd use one of these things in the
    future.
     
    Paul B. Andersen, Jul 5, 2015
    #94
  15. I asked for the iPhone newsgroup because the overall problem
    has a LOT to do with the three pieces of equipment the girls
    have in Europe, which are:
    1. iPhone (the other kid)
    2. iPads (both kids)
    3. Android (my kid)

    Plus, it's a perfectly valid question to ask how an iPhone user
    (such as the girl in Europe at this very moment) can sniff out
    what the problem is with her WiFi connection.

    To this day, only the Android phone has WiFi connectivity at
    their location. Both iPads and the iPhone are NOT connecting
    to the (admittedly) weak WiFi of the brother-in-law's residence.
     
    Paul B. Andersen, Jul 5, 2015
    #95
  16. Paul B. Andersen

    nospam Guest

    you're once again overcomplicating things.

    there is *no* need for wifi analysis apps to get an ipad connected to
    wifi.
    then there's something wrong with the base station.
     
    nospam, Jul 5, 2015
    #96
  17. Paul B. Andersen

    Char Jackson Guest

    First, when you use terms such as 'same' and 'different, you're exclusively
    comparing an aspect of the repeater (extender) or AP to that same aspect on
    the primary WiFi router, correct? Client behavior is not part of that
    comparison. Clients always follow (or not) what they're connected to, if
    possible.

    So with that in mind...
    Correct for both of those.
    Same or different channel, same or different SSID. When you set up an AP,
    you're completely free to use any channel (you already know the "rules"),
    and any SSID. Those decisions are not dictated by the settings on the
    primary WiFi router.
     
    Char Jackson, Jul 5, 2015
    #97
  18. Paul B. Andersen

    Char Jackson Guest

    That's wrong, but I think you've since corrected that.
     
    Char Jackson, Jul 5, 2015
    #98
  19. Paul B. Andersen

    Char Jackson Guest

    Independence Day ;-)
     
    Char Jackson, Jul 5, 2015
    #99
  20. Paul B. Andersen

    Char Jackson Guest


    I think Jeff is referring to the AP<->Client relationship, while I think
    you're referring to the AP<->primary WiFi router relationship. You're both
    right, but talking about different things.
     
    Char Jackson, Jul 5, 2015
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