new iPad, LTE, and signal bars

Discussion in 'iPad' started by Fynd, Mar 19, 2012.

  1. Fynd macrumors 6502

    Aug 11, 2010
    Just curious if anyone has any input on this. I'm stuck at 1 to MAYBE 2 bars tops in a full coverage LTE area with very few customers, and regardless where I am in the city I still remain at 1-2 bars tops. The strange part is that it seems to be totally wrong, as I get 30/30 speeds consistantly, and have no signs of poor reception.

    I noticed alot of people posting screens of their new iPads for various reasons also appear to have a very weak signal....

    I read somewhere that perhaps iOS isn't showing the reception properly, and is basing it on 3G signal strength?

    I'm with Rogers, in Newfoundland for what it's worth.
  2. Sneakz macrumors 65816


    Jul 17, 2008
    Toronto, Ontario, Canada
    FWIW, I'm in Toronto on Telus LTE and I haven't seen more than two bars. I can still achieve speeds of 30/20 so I wouldn't look to much into it. Also, LTE in Canada right now is on AWS spectrum instead of the 850MHz (UMTS Band V) we enjoyed with HSPA. Signal penetration is lower currently with AWS.
  3. mobile-caffeine macrumors member

    Apr 13, 2010
    I'm in Toronto on Rogers and CANNOT get an LTE signal to save my life. It's been in 3G the whole time. The moment it changes to LTE it drops the signal to "no service" and when it comes back it says 3G. I spoke with tech support and they say it's a faulty SIM. I wonder if it's a faulty network?? I wonder if Bell or Telus is better in Toronto. Anybody know?
  4. babo macrumors newbie

    Mar 19, 2012
    I'm in downtown Toronto and with Bell and am struggling to get a signal. Sometimes I'll get 1 bar LTE with speeds of 6Mbps. Up in Markham today the connection is much better 4 bars with speeds of 30Mbps. Can't say I'm impressed with the service downtown and was hoping another carrier would offer better signal.
  5. Fynd thread starter macrumors 6502

    Aug 11, 2010
    Thanks for the reply Sneakz, interesting.

    Oddly enough since this was posted Rogers has clearly changed something... My phone was kicked offline for an hour, and now suddenly I have the hotspot option on my iPad that was missing. I'm now getting 2 and 3 bars on LTE, consistantly too.

    I didn't call support, either, as I was planning on doing to solve the hotspot issue. Don't have to now I guess.

  6. bradpaulp macrumors newbie

    Aug 12, 2011
    signal bars not signal in negative number (db)

    I know this is slightly off topic but it seems that your iPads show actual BARS for signal strength on the LTE/3G networks?

    I have the new iPad (3rd gen) for Verizon, and it shows a negative number for signal strength. best resource online I can find is closer to 0 the better. But its odd, Ive never seen an iPad like this before. Is this default, do you know how to change, id rather see a traditional bar.
  7. AllieNeko macrumors 65816

    Sep 25, 2003
    Your iPad that shows the number is somehow in service field test mode. On an iPhone you dial *3001#12345#* to get there. Since that can't be done on an iPad who knows how you ended up there...

    Anyways, that number is dBm (decibels referenced to 1mW). In real life, you're not likely to ever see about -50 or so. -50dBm is 0.00001mW. Or 0.00000001W. Thus, the reason why all the cell phone cancer worriers are insane.

    Also, they love to talk about the absorbed radiation (SAR) from their phones. SAR is calculated assuming maximum transmit power. You're almost NEVER there. I just made a test call on my iPhone. Right now I'm in a call and my received power is -87dBm and my transmit power is 7.30dBm (though that's a real time reading and bouncing around a lot but it's going above and below that a lot), and simply by moving my phone a bit and holding it upright the transmit power fell to -19dBm. That means that I was transmitting in position 1 at 5.37mW and in position 2 at 0.0126mW. The SAR rates are determined transmitting at full power (generally around 200mW/23dBm).

    Your Wi-Fi devices run at higher power levels in the real world than your cell phone does. Cell phones use active transmit power control to keep your signal level as low as possible. Wi-Fi will always transmit at a constant level (17dBm/50mW is common) when it is transmitting. Yet, most of the cell phone cancer worriers claim Wi-Fi is less harmful due to the lower power level. Nonsense. Most of the time, the power level of Wi-Fi is much higher. Same with home cordless phones.

    How can cell phones operate at such low power levels? The receive sensitivity is amazing. You can be at -113dBm (generally the floor on most UMTS radios) and still hold a call. -100dBm is still perfectly usable and results in good performance. Try that one with Wi-Fi or other ISM band cordless products - your at your noise floor or even below it. Licensed exclusive-use spectrum lets power levels be very low.

    Okay, so I guess that's me rambling on far too long, but the point is, that's the number you're seeing and it's very nice to see! Most cell phones show full bars around -80dBm, but often use more than just received power level to calculate "bars" so it's not an exact science. Also, in a dual band market, bars mean even less. For example, in my area AT&T runs UMTS on both 850 (CLR) and 1900 (PCS). If I'm on a PCS channel I can be outside and below -100dBm with just one or two "bars" on my phone, and walk inside a building and get full "bars" and -80dBm or better, because my phone hops onto an 850/CLR channel

    To the OP, ignore the bars, they mean very little...

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