Do you know where we can find the 3 key WiFi specs for the iPad?

Discussion in 'Wireless Internet' started by Liam O'Connor, Mar 1, 2014.

  1. Liam O'Connor

    Guest Guest

    i have many phones here, from flip to candybar to iphone to android,
    and they all drop in signal strength depending on where i hold it.
    no you didn't.

    the iphone 3g is gsm only. there is no cdma.

    the iphone was an at&t exclusive until the iphone 4 cdma in early 2011.
    at&t had a lot of issues, especially in the bay area. there were a lot
    of dropped calls well before the iphone 4, as well as shitty data
    speeds. they were overloaded, big time. they didn't expect the iphone
    to be as successful as it was.

    in fact, at&t was the #1 complaint from iphone users early on.
    what proof do you have that's what they did, when they said they didn't
    do anything?

    and at the end of the day, the user doesn't care *why* a call didn't
    drop, only that it didn't.
    depends if i'm having serious problems or not.

    changewave is in the business of surveys. they ask a statistically
    valid sample. the majority (by a lot) didn't have a problem.
    in fact, they did ask about that, and not that many said it was
    serious. i need to find the actual survey though for specifics.
    those help but not required. that was mostly to get the whiners to stop
    whining.

    note that after the free bumper offer ended, there weren't very many
    additional complaints.
    pretty much.

    if it isn't affecting anyone, then how is it even a problem?
    interesting story, but i don't know what that has to do with anything.
    apple has likely sold at least 100 million iphone 4 over the past 3+
    years (they don't give specific model breakdowns).

    they sold 51 million iphones last quarter *alone*.

    the reality is that most users did not find it to be a problem. at all.

    however, the number is never going to be zero. if you touch the
    antenna, the signal strength will drop, just like any phone.

    people like to complain.
    i picked a couple of videos that show the effect of 'holding it wrong'.
    or it's part of actual effects.

    i have a flip phone where the instructions say how to hold it, and if i
    hold it the way it says not to, the signal strength drops.
     
    Guest, Mar 2, 2014
    #21
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  2. Wow. That's six times the power, not just doubling.

    I officially will give up on my prior assumption
    that the power gain at 5GHz was twice that at 2.4 GHz.

    It's actually 5.62 times the power!

    Thanks for explaining.

    The important takeaway is that the iPad antenna has
    4.2dB more gain at 5.7GHz than at 2.4GHz (which means
    the iPad transmits 2.6 times as much power at 5.7GHz
    as it does at 2.4GHz).

    Note: My conversion of dB to power factor are from here:
    http://www.sengpielaudio.com/calculator-db.htm
     
    Liam O'Connor, Mar 2, 2014
    #22
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  3. Oops. My apologies and my faulty memory (again).

    Starting in about 2006, I used a XV6700 on Verizon. Not the best
    audio or range, but no disconnects:
    <http://802.11junk.com/jeffl/xv6700/XV6700.htm>
    Starting in about 2009, I used an iPhone 3G on AT&T for only about a
    week after which I discontinued the service due to poor coverage in my
    mountain area. For the next year or so, I went through a variety of
    used phones on Verizon. Since the iPhone 3G was mine, I carried it
    around as a PDA for about 2 years after pulling the plug with AT&T.
    After that, I retired the iPhone 3G and switched to a Droid X and
    later a Droid X2. For cellular voice, I use, an old LG VX8300 phone
    on Verizon.

    The reduction in dropped calls on my friends AT&T iPhone 3G's was
    quite real.
     
    Jeff Liebermann, Mar 2, 2014
    #23
  4. This is an excellent idea!
    Thanks!
     
    Liam O'Connor, Mar 2, 2014
    #24
  5. Liam O'Connor

    Guest Guest

    they probably added capacity, which they said they would be doing
    because it was so horribly overloaded.
     
    Guest, Mar 2, 2014
    #25
  6. Hi Jeff,

    That's pretty interesting, because, well, um, I had assumed
    that they almost always lie when it comes to specifications.

    The WiFi chip found in this iPad teardown
    http://www.ifixit.com/Teardown/iPad+Wi-Fi+Teardown/2183

    Is the Broadcom BCM4329:
    http://www.broadcom.com/products/Bluetooth/Bluetooth-RF-Silicon-and-Software-Solutions/BCM4329

    Googling for the specs for that broadcom chip, I "think" I found
    them on page 6 of this document:
    http://www.lairdtech.com/WorkArea/DownloadAsset.aspx?id=2147486570

    Do those specs look reasonable for that chip?
     
    Liam O'Connor, Mar 2, 2014
    #26
  7. <http://investorplace.com/2010/08/apple-inc-iphone-4-survey-att-verizon/>
    See the red bar graph showing iPhone 4 dislikes. 24% listed "antenna
    issues" as what they "most dislike" about the iPhone 4. What someone
    dislikes the most is a great way of reducing the incidence of lesser
    complaints. For example, users were given a choice of "most dislike"
    of requiring using the AT&T network, and coverage, speed, and of the
    quality of the AT&T network. The result was 27% and 24% respectively.
    What this did was effectively split the complaints about AT&T roughly
    in half. If they had only offered AT&T complaints as a single "most
    dislike" choice, the combined total of 51% would have indicated that
    at least half the users were not thrilled with AT&T. Similarly, the
    participants were given the choice of "dropped calls" and "antenna
    issues" again effectively splitting the complaints. If I assume that
    all dropped calls were precipitated by the antenna problem (not system
    overload), then at least 47% were having problems. If they had asked
    "Which of the following do you dislike about the iPhone and about
    AT&T. Pick all that apply", it would have been a very different
    survey.

    Of course, there's something wrong with the numbers anyway, as the
    total of the percentages adds up to 129% instead of 100%.

    The article claims:
    To gauge the impact of the antenna obstruction issue, we
    asked iPhone 4 owners to tell us how big of a problem it
    was for them. Nearly two-thirds reported they Haven’t
    Experienced Any Problem and another 14% reported it
    Wasn’t Much of a Problem. However one-in-five did report
    it was Somewhat of a Problem (14%) or a Very Big Problem (7%).
    So, 14+14+7 = 35% of the users were having a problem. I guess Apple
    has such a large customer base, that it can afford to ignore 1/3 of
    it's early adopters.

    Full disclosures. I used to craft such surveys in the late 1980's but
    haven't done much since then. I would be interested in seeing the
    original survey. They usually charge for reports:
    For every customer that actually calls tech support with a real
    problem, it can be assumed that there is a fairly large number of
    users that simply didn't bother to call. I've worked on a few
    products that had this problem. We didn't know that something was
    wrong until one customer made considerable noise at a trade show,
    followed by plenty of "me too" complaints. Kinda like priming the
    pump. Unfortunately, it's quite common to run a business these days
    on the basis of no complaint = no problem. The result is that some
    brilliant manager decides that it's easier to discourage complainers
    than it is to fix the product. I wrote this about 20 years ago in
    honor of such brilliance:
    <http://members.cruzio.com/~jeffl/poetry/support.htm>

    More examples of products that don't work, and few or nobody
    complains:
    It demonstrates that customer complaints and product defects are not
    directly connected. It is quite possible to have a problem, and
    nobody complain, as I found out. I can supply other examples of this
    if you are not convinced.
    True. iPhones are not the only products that sell well but have
    defects. I see them all the time in the computer biz. For example,
    Dell was (allegedly) knowingly selling computers that had defective
    electrolytic capacitors known to bulge, leak, and fail in a fairly
    short time. Various laptop vendors did much the same with lousy BGA
    soldering (and blamed on bad Nvidia chips). They sold quite nicely,
    even during the various class action suits and settlements which
    provided the only way consumers even knew that there was a problem.

    Perception is everything, and the perception of Apple products is
    truly impressive.
    They drop by differing amounts, measured in dB. Did you measure the
    signal levels as I suggested in my previous message? I have a mess of
    phones in the office that I can measure on Monday or Tues. If you
    need help getting into the test mode:
    Some people do, but most don't. They simply don't consider the effort
    necessary to file a proper complaint worthwhile. Also, many companies
    have no mechanism for complaints. For example, about 4(?) years ago,
    I had a firmware update failure that trashed an Apple aluminum
    Bluetooth keyboard. The installer would not let me go back a version,
    not let me reinstall, and there was no later version. I asked for
    help on various forums and to various email addresses with little
    result. When I changed my questions to complaints, my postings were
    deleted from the Apple forum and my account locked.
    I saw little in the way of an effect except to see 1 or 2 bars go to
    zero. No dropped calls. I have several phones that will successfully
    make calls with no bars showing. I want to see the change in signal
    level in dBm before and after.
    It's still not sinking in. Go to:
    <http://802.11junk.com/jeffl/cellular/cell-test.htm>
    All the ordinary cell phones lost signal when the antenna was covered.
    Most lost 5 to 8 dB in signal, which is considerable, but not fatal in
    moderate signal areas. The worst was 12dB. However, the iPhone 4
    lost between 19.8dB and 24.6dB which is enormous, huge, monstrous, and
    full able to create a dropout. When I did the tests, we didn't have
    the iPhone 4 rubber protectors available, but I can test those when I
    have time and add them to the table.

    To put the numbers in perspective 5 to 8dB is about 3.2 to 6.3 times.
    The iPhone 4 19.8dB to 24.6dB is 95.5 to 288 times drop in signal.
    That's like trying to operate with 1/100 to 1/200 of the normal signal
    level.

    Now do you understand the problem?
     
    Jeff Liebermann, Mar 2, 2014
    #27
  8. I used to track cell sites in the Santa Cruz county area. This is a
    really old (2003). I have some spreadsheets and maps with current
    cell site locations and capabilities:
    <http://802.11junk.com/cellular/index.html>
    The plan was to make an overlay of the coverage areas by vendor, but
    that ended when I landed in the hospital for some major surgery. This
    is the only map that I managed to do at the time:
    <http://802.11junk.com/cellular/jeffl/SVLY-PGE/index.html>
    See map at bottom of page. Since then, the coverage maps produced by
    Radio-Mobile have been considerably better:
    <http://802.11junk.com/jeffl/coverage/VZW-water-plant/850Mhz-2watts-39dBu.jpg>
    <http://802.11junk.com/jeffl/coverage/Boulder-Creek-Cellular/850Mhz-1watt-16dbi-15meters-3D.jpg>

    At the time (about 2010) there had been some growth in the AT&T system
    in the downtown areas and along the major highways. It was not
    spectacular. In the mountains, where I live, there has been no
    changes in the AT&T system since about 2001. The biggest build was
    the shared DAS system at the local university (UCSC). The sites are
    at the telco CO's, on a few local hills, 2 small sites, and nothing
    more. I can't find my spreadsheet with the locations or I would be
    more specific. I think (not sure) that all 3 of my iPhone using
    friends were in moderate signal areas, where they would not be
    significantly affected by additional cell sites, but would be affected
    by additional users.

    2AM. Enough for tonite...
     
    Jeff Liebermann, Mar 2, 2014
    #28
  9. No. The problem is that the module is using an XM2400LT for a 2.4Ghz
    receiver preamp, and a SKY65404 rx preamp, and an RTC6651 tx power amp
    on 5.7GHz. See Pg 5, Fig 1, in the Lairdtech document. Because the
    iPad is NOT using any of these additional chips, all the numbers will
    be different.

    WHICH MODEL IPAD DO YOU HAVE? FCC ID or APPLE MODEL NUMBER.
     
    Jeff Liebermann, Mar 2, 2014
    #29
  10. Liam O'Connor

    Guest Guest

    only 7% had a major problem. that's very low, just as i said.

    'nearly two-thirds reported they haven't experienced any problem'.
    that's a lot.

    it also means the entire thing was overblown. most people did not find
    it to be a problem *at all*.

    add in the 14% who said it wasn't much of a problem and you have almost
    80% who are either not impacted at all or only slightly. almost 80% !!!

    the capacitors were not dell's fault. dell bought what they thought
    were good capacitors, as did many other companies, and they turned out
    to be defective. a lot of companies were affected, including apple.

    the nvidia chip delamination issue also affected many companies,
    including apple, who issued an extended repair program because of it.

    and users found out the hard way, because their products ceased to
    function.
    not really.
    what matters is does the phone work in normal day to day operation and
    can the user make and receive calls without dropping and do whatever
    tasks they want to do.

    it does, and they can.
    that's a formal complaint.

    you said there were a lot of hits on google. that's *not* a formal
    complaint.

    it takes almost no effort to post on a forum that a product isn't
    working properly or there's some other problem with it (even if it's
    minor), the user hates the product etc. type up a rant, and a few
    clicks later it's posted for all to see.

    it's very rare to see people post that they like something. it happens,
    but not as much as complaints.

    and this isn't just tech. people complain about everything more than
    they do praise. it's human nature.
    apple has mechanisms for complaints. did you avail yourself of it?

    if you took the bluetooth keyboard to an apple store, they would have
    fixed it or replaced it.
    exactly my point. all phones are affected.

    that includes the iphone 4. it's no different.

    physics is physics.
     
    Guest, Mar 2, 2014
    #30
  11. Liam O'Connor

    miso Guest

    If I remember to turn of the wifi or block the autoconnect, then it isn't a
    problem. But you grab the phone and leave the house, and forget to change
    things like switch off wifi. I'm waiting for the next rev of my phone OS,
    then I can use a NFC to change the phone parameters. That is, leave a NFC in
    the car and the phone will automatically be set. Right now all I can do is
    program tags and read them as messages or URLs.

    There is no enforcement of IEEE specs. Often manufacturers say they are
    "compatible" with a spec, which doesn't mean they meet the spec.

    Speaking of NFC, I think we get chip and pin credit cards in 2016. Well
    unless more corrupt politicians are purchased. I'd really like some scheme
    where my receipt is feed NFC. I don't mind using a card, but hate the paper,
    and am paranoid that someday the receipt will be useful.
     
    miso, Mar 2, 2014
    #31
  12. Liam O'Connor

    miso Guest

    No seriously, Apple sucks in the RF department. They are a class of shit to
    themselves. This isn't a secret. But the idea of the iphone is to having a
    gaming machine, so the RF issues are secondary.

    Note for LTE, they use two antennas. This is part of the standard. That is,
    everyone uses at least two antennas for LTE. This should make the iphone
    suck less.

    What they really need to do is hire some good RF engineers. If they drop the
    style (i.e. useless metal on the phone) for good engineering, Apple could be
    as good as the rest of the market.

    Look at those cheap Droids. Totally killer RF at half the price.
     
    miso, Mar 2, 2014
    #32
  13. Liam O'Connor

    miso Guest

    The iphone dropped calls are due to something besides the antenna. I've seen
    the phone drop calls when not moving. I suspect some issue in IOS. The
    iphone declares "call failed" out of the blue.
     
    miso, Mar 2, 2014
    #33
  14. Liam O'Connor

    Guest Guest

    depends on the carrier. at&t is well known for dropped calls.
    bullshit.
     
    Guest, Mar 2, 2014
    #34
  15. Hi Jeff,
    Thanks for that advice.
    I always appreciate your help.

    If I go to my settings in the iPad Air, I find the following:
    Settings->General->Software Update = iOS 7.0.6
    Settings->General->About->Version = 7.0.6 (11B651)
    Settings->General->About->Carrier = T-Mobile 15.5
    Settings->General->About->Model = MF534LL/A

    Hmmmmmm..... I was expecting a different model number.

    Getting out a (real) magnifying glass, I see on the back bottom:
    Model A1475 FCC ID: BCGA1475 IC: 579C-A1475
     
    Liam O'Connor, Mar 2, 2014
    #35
  16. Liam O'Connor

    Guest Guest

    troll.

    first of all, no product has a 0.07% failure rate. that's just not
    realistic.

    second of all, the proper comparison is with other similar phones, not
    zero, and you'll see it's not significantly different.

    all cellphones have the same problem to a certain extent, and in some
    cases, it's worse with others than it is for an iphone.
    i've had to repair the brakes twice in the past 4 years, once on each
    of two cars.

    the power goes out a few times a year typically, and was flickering a
    couple of weeks ago but didn't go off completely. a couple of years ago
    after a big storm, it was off for 2 days.

    it sucks when it happens but nothing is perfect.

    not that either one is relevant. if the signal strength drops a little,
    it's not a big deal.
    then computers are far too complicated for you.
     
    Guest, Mar 2, 2014
    #36
  17. The Wi-Fi Alliance certifies that tested devices meet the major IEEE
    802.11* specs.
    <http://www.wi-fi.org/certification/programs>
    A fair number of devices have only some of their features certified.

    There are also proprietary enhancements and privatized versions of
    common specs, such as Apple's Airprint as an "extension" of IPP
    (internet printing protocol). At this time, the Wi-Fi Alliance does
    not certify printing protocols, but that might change real soon.
    I haven't seen that. If they have the appropriate logo or
    certification number, they passed the test.
     
    Jeff Liebermann, Mar 3, 2014
    #37
  18. I can't say anything about that for obvious reasons. However, I can
    point out an oddity. Apple has posted an ever increasing number of RF
    engineer job openings for approximately the last year or so.
    <http://www.linkedin.com/job/q-rf-engineer-c-apple-jobs>
    24 are in the SF Bay area. The odd part is that postings are reposted
    as new openings every 2 weeks or so, sometimes with minor changes. To
    the best of my limited knowledge, they haven't hired anyone. Maybe
    their looking for an excuse to bring in some more H1B employees
    working for below industry pay scale. Dunno.
    For me, it's mostly a camera and an HP41 calculator emulator.
    It's the style and the perception of quality that sells the phones. I
    don't think that Apple is going to drop that.
    Ummm... my Droid X and Droid X2 offer far from stellar RF performance.
    Same with various other Android smartphones I've tested. The limiting
    factor is controlling SAR (specific absorption rate), which is a
    problem with all phones.
    <http://reviews.cnet.com/cell-phone-radiation-levels/>
    The limit is 1.6 W/Kg. Most Apple phones coming in around 1.2 W/Kg.
    Not too bad. However, the worst phones are mostly Android
    smartphones:
    <http://reviews.cnet.com/2719-6602_7-291-2.html>
    Of course, some manufacturers cheat by reducing the maximum TX power
    of their phones in order to meet the SAR specification. If that
    happened, you should see the lower numbers in the FCC ID pages for the
    phone. I would lookup the power levels but the FCC ID site is still
    belching errors (on 2 different computahs and one tablet).
     
    Jeff Liebermann, Mar 3, 2014
    #38
  19. Liam O'Connor

    Guest Guest

    that could be for any number of reasons, including the 'new product
    categories' they have said they're working on.

    nevertheless, conspiracy theories abound.

    and they definitely don't suck in the rf department.
     
    Guest, Mar 3, 2014
    #39
  20. Jeff Liebermann, Mar 3, 2014
    #40
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