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

    My daughter is traveling in Europe with a friend, where my
    daughter has the Nexus 5 while her friend has one of the
    newer iPhones (I don't know which one). Both have iPads also,
    but neither iPad (AFAIK) is picking up cellular. Both
    traveled with a single carryon, so, they have no PCs.

    The grandparents are on dialup (they're in their 80's) but
    my brother in law lives next door, through thick walls, where
    my daughter is reading -90dBM signal strength on InSSIDer
    freeware (installed before InSSIDer started costing $10)
    for the brother-in-laws access point.

    They can't connect to WiFi, and it's driving them (typical
    American kids) crazy. What I would like to know is the
    headroom over the SNR (signal to noise ratio) so I need to
    have them measure the noise level (at either 2.4GHz or 5GHz).

    Do you know an app that provides the SNR or the noise level?

    They're currently "surviving" on the fact that my daughter
    is on T-Mobile so the personal hotspot feature allows her
    (unlimited but slow 3G at best) cellular data to be shared
    with the AT&T iPhone and to both iPads.

    My daughter called the free T-Mobile international phone
    number 611-equivalent (+1-505-998-3793) and they had her
    turn on roaming, which gave her 3G (at best) cellular
    data (where the T-Mobile plan is unlimited data when in
    Europe, but only something like 2.5GB/month in the USA).

    I know less about the AT&T iPhone but the friend seems to
    have only an 800MB/month plan but she can't connect for
    cellular data for some reason, so she's glomming off my
    daughter's signal for the moment (until we sort this out).

    I don't know the situation with the AT&T iPad, but the
    T-Mobile iPad only has the free 200Mb/month for life
    SIM card, which doesn't work in Europe, so it's a "dumb"
    iPad with respect to cellular data (it should work fine
    on WiFi though).

    Since the T-Mobile Android cellular data is slow (3G at
    best according to T-Mobile) and has to be shared with
    the AT&T iPhone, I really want both of them on the
    next-door brother-in-law's home broadband router WiFi.

    Jeff Liebermann kindly suggested the freeware WiFi
    Analyzer, which is as good as InSSIDer so, we have
    both installed now, and that tells us the signal strength
    in decibels (my daughter is getting -90dBm but can't
    connect to the WiFi access point for some reason).

    The reason they can't connect is almost certainly that
    the signal to noise ratio doesn't give them the 10 to
    12 decibels they need of headroom.

    But, that brings up this question because I have no
    idea what the noise level is at their location.

    Is there a way to get WiFi NOISE levels for any of
    these three types of mobile devices?
    Paul B. Andersen, Jul 1, 2015
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  2. Ummmm... WiFi-SNR perhaps?
    That catch is that you have to be connected to the remote access point
    in order to generate a graph. Also, dive into "Setting" and check the
    "Display results in text" box. I'm sitting about 3 ft from my AP and
    it shows an average of about 40dB SNR.
    Jeff Liebermann, Jul 1, 2015
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  3. Paul B. Andersen

    chris Guest

    I use wifi analyzer on Android. I think Apple restrict access to that
    information in iOS so I think most apps are limited on that platform
    unless they're jailbroken.
    chris, Jul 1, 2015
  4. Thanks for that idea, as I had not found that app in my search.
    Here is a screenshot run from home just now of the results:

    Compare that with InSSIDER results and I like WiFiSNR *much better*!

    So WiFi_SNR is an instant keeper!

    I had previously only found (and installed) the following freeware
    1. WiFi Analyser
    2. WiGLE WiFi
    3. Fritz!App WLAN
    4. Fing
    all of which do very nice things, with lots of bells and whistles, but
    none seemed to report the SNR or noise level in decibels.

    Loading WiFi-SNR on my Android phone, it immediately tells me that the
    signal strength should be between 0 & -60dBm for a good WiFi connection.

    The help is great, as it then tells me that I need a SNR of at least 10
    to get decent WiFi speeds, and then it explains the WiFi Link speed,
    which is automatically adjusted by the ROUTER (not the phone!)
    depending on the SNR (so the router apparently knows the SNR all the
    time). Interesting.

    Then it displays real time graphs, at 1-second intervals, for:
    1. Signal to Noise Ratio (I had to turn on text output to *see* it)
    2. Link Speed
    3. Signal Strength

    In my results at home (testing it before I tell my kid to use it):

    Turning on the nice *text* output...
    1. My SNR averaged -69dB
    2. My Link Speed to the home broadband router averaged 41Mbps
    3. My Signal Strength from the home broadband router averaged -68dBm

    I think it's interesting that my signal strength is about the same
    as my SNR, but they're two different things, so, what it means is
    that I have a decent signal strength of -68dBm and way more than
    the necessary ratio of 10 for the signal-to-noise ratio.

    Now to talk the kid through all this (they're 9 hours ahead of me
    Paul B. Andersen, Jul 1, 2015
  5. On Android, I had previously already installed this freeware:
    1. WiFi Analyser
    2. WiGLE WiFi
    3. Fritz!App WLAN
    4. Fing
    5. InSSIDer (no longer freeware)
    all of which do very nice things, with lots of bells and whistles, but
    none seemed to report the SNR or noise level in decibels.

    Your suggestion of WiFi Analyzer is pretty good as it has 5 pages:
    1. A real nice hand-held beeping signal strength analog meter!
    2. Signal strength graphs for 2.4GHz
    3. Running timelines of signal strength graphs
    4. Signal strength bars, with security, SSID, BSSID, channel, router, etc.
    5. Some kind of channel quality histogram

    A picture of each, for those who don't have it, is below, from a test
    at home just now on my phone:

    These tools are so useful, especially when debugging a problem from
    afar, that I don't know how I lived without them in the past!

    Thanks for all the suggestions. I will no longer be ignorant of
    what is actually going on, and, I'll be better equipped to
    troubleshoot given the necessary technical data.

    Paul B. Andersen, Jul 1, 2015
  6. Paul B. Andersen

    Rod Speed Guest

    Crashes every time you enter settings on a Galaxy Tab 2
    Rod Speed, Jul 1, 2015
  7. Oh, they are WAY MORE ahead of you than that, dad! :)
    Allodoxaphobia, Jul 1, 2015
  8. I know what you mean.

    Actually, my kid is pretty technical for a girl. Most girls can
    get boys to help them so they never learn. You only learn when
    you have to do *everything* by yourself, so, kids, in general,
    and girl kids in particular, get a *lot* of help in the simplest
    things (like setting up a wifi hotspot).

    The other kid, with the iPhone, still hasn't figured out how
    to get the phone working, nor her iPad, so, at the moment,
    both kids are using the setup that my kid did on Android.

    Up until now, I've set up everything for my kid.
    But with her being on her own, she had to learn things
    and nobody there knew enough technically to help her.

    1. She had to learn, on her own, that ROAMING had to be
    turned on (in the USA, it wasn't an issue).

    2. She had to learn, on her own, how to set up a WiFi
    hotspot (with ubiquitous WiFi in the USA, and good cellular
    data, she didn't have the need in the USA). [And she knew
    enough to ask me what the difference was between tethering
    and personal hotspots.]

    3. She had to learn, on her own, how to use and interpret
    the WiFi software (I give her credit for trying and asking
    me what a decibel was, and for realizing it's negative for
    a reason).

    4. She had to turn off her data limits (in the USA, T-Mobile
    limits us to 2.5GB/month, but in Europe, it's unlimited).

    5. She had to learn how to find the decibels of the nearest
    cellular tower in the Android settings and to then select
    one of the four T-Mobile roaming partners as the preferred
    network in the network options.

    6. Once she had that, she had to learn how to use Skype
    VOIP (yes, I know it's easy for you and me, but she has
    never had a need for VOIP before as we have a VOIP telephone
    with remote handsets throughout the house and she didn't
    have to set anything up for it. She just dials.)

    7. She even had to figure out, on her own, how to set up
    the SSID and password for the brother-in-law's router
    (up until now, someone has done all of that for her).
    And how to set up WiFi calling (T-Mobile says calls from
    her to and from the USA are free if they are on the WiFi
    calling setup).

    8. On her iPad, she had to learn to shut off the cellular
    data for specific apps (which is a nice feature of iOS
    that I don't think Android has as part of the OS).

    Plus a bunch of stuff I don't remember.

    In contrast, her friend is *still* unable to connect to
    AT&T by cellular and she already racked up a huge bill
    (her parents told me it was over $300 already but they
    let AT&T talk them into a different plan where they
    won't charge them the $300 and she gets a different
    plan instead).

    My point is that my daughter did step up to the plate,
    as it's her first trip without me to Europe, and she
    has learned what she needed since she needs the Internet
    to survive. :)

    Meanwhile, her friend, on the iPhone, still doesn't have
    any cellular Internet and is using my daughter's AP (which
    is OK by me, since it's free - but it will slow
    things down a bit having all four devices use the same
    3G-at-best cellular connection).
    Paul B. Andersen, Jul 1, 2015
  9. Paul B. Andersen

    Char Jackson Guest

    It's negative if it's less than the value that it's being compared to.
    Obviously, it's positive if the comparison is the other way around. You
    probably know that, but a casual reader (me) did a double take.
    Char Jackson, Jul 2, 2015
  10. Paul B. Andersen

    Char Jackson Guest

    And the same for 5GHz.
    Char Jackson, Jul 2, 2015
  11. Jeff Liebermann, Jul 2, 2015
  12. I skimmed around the various wi-fi tools available and it was the only
    one that produced real SNR numbers. There was one other that tried,
    which incidentally has the same name as WiFi Analyzer:
    Try using remote control software to tweak her handset. Teamviewer
    works on just about everything:
    You don't have to use a smartphone to manager her smartphone. Install
    it on a desktop or laptop, and use that to run her smartphone. The
    catch is that she will need a good wi-fi connection in order for you
    to run her phone. It won't work for dealing with the low wi-fi signal
    problem, but it can certainly help with checking settings, installing
    software, etc.

    Speaking of installing software... the right way is to use the Google
    Play Store. Have your daughter give you here Google login and
    password. She'll no doubt protest but threats of instant
    impoverishment should change her attitude. Login to Google on your
    machine and go to "My Apps".
    From there, you can install any application on her phone. The next
    time she connects via Wi-Fi, the selected apps get downloaded and

    However, there's a catch. For some dumb, stupid, and unfathomable
    reason, Google does not allow you to uninstall an app using the play
    store web page. It also doesn't allow you to remove apps from the "My
    Apps" mess, even if you're decided that they're worthless and have
    already uninstalled it. My growing "My Apps" mess has about 400 apps
    of which I have only about 100 installed (and use maybe 10).
    Jeff Liebermann, Jul 2, 2015
  13. Jeff Liebermann, Jul 2, 2015
  14. Yes. The way I think about it is that, at 0dB, you're the same as the
    standard (which is usually 1mW but it could be any standard of power).

    At 3 dB, you're three times the power of the standard.
    At -3 dB, you're half the power of that standard.

    The standard happens to be really big compared to what phones can
    muster, so, we're minus a pretty big number (where every 3dB is
    yet another halving of the power).

    By the time you get to -60dB, you've halved the power 20 times
    successively (1/2 of 1/2 of 1/2 of 1/2 etc.), which is really
    a teeny tiny amount of power *compared to the standard*.
    Paul B. Andersen, Jul 2, 2015
  15. I think your find is GREAT!
    I had searched and didn't find it, so, I APPRECIATE the advice!
    I had concluded (erroneously) that there were no programs that provide
    the SNR, but this one does.

    One catch is that I had to turn on the text display in the settings
    in order to *see* the SNR graph, but that's a minor catch and easily
    That's an interesting idea. I hadn't realized it would be so easy
    to remotely control a handset. I'll keep that in mind for the future.
    That's also very interesting.

    I hadn't realized WHY Google Play even has URLs since I have never
    installed *anything* onto an Android or Apple device via a URL.

    It's nice to know I can basically put it in her "shopping cart",
    and then the kid gets it whether she wants it or not when she
    connects to WiFi. Interesting way to pre-install software for
    a kid (especially if they keep removing it, such as with the
    automatic phone recorder app my youngest kid keeps removing).

    I don't want my kids uninstalling stuff I sneak on there,
    so that's fine.
    Paul B. Andersen, Jul 2, 2015
  16. For some reason, I didn't *see* the 5GHz graphs, so, that's
    why I listed it that way. I only saw 2.5GHz graphs. I didn't
    debug why (maybe I just missed them somehow, as I know my
    router has a 5GHz SSID broadcast).
    Paul B. Andersen, Jul 2, 2015
  17. Another way to look at the SNR headroom that is causing the problem here,
    given that every 3 decibels is a factor of 2x the power, if we want 9
    decibels of headroom over the noise, that's 2x2x2=8 times the signal
    as we have noise.

    Since 9 decibels isn't usually enough, we really want more than 10, so,
    let's say they get 12 decibels of signal over the noise, that would
    be 2x2x2x2=16 times the signal as there is noise.

    That's about the minimum for a decent connection to WiFi.
    Paul B. Andersen, Jul 2, 2015
  18. Ooops. I didn't proof read.

    At 3 dB, you're *two* times the power of the standard.
    At -3 dB, you're half the power of that standard.
    Paul B. Andersen, Jul 2, 2015
  19. Paul B. Andersen

    The Real Bev Guest

    I use the 'applications' button (bottom, looks like a dot-grid) to find
    the app I want. Long press, drag it up to 'info' or whatever seems
    likely, clear the cache and uninstall it. At least that's how it works
    on my Samsung tablets and BLU and Motorola phones. The 'apps' thing in
    the settings menu is relatively worthless.
    The Real Bev, Jul 2, 2015
  20. Paul B. Andersen

    chris Guest

    Probably because your device doesn't do 5GHz. I see the same on my Moto
    G which is 2.4GHz capable only.
    chris, Jul 2, 2015
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