Resolved 6s Signal Strength Drops Dramatically

Discussion in 'iPhone' started by aKansasKid, Nov 28, 2015.

  1. aKansasKid macrumors regular

    Apr 27, 2015
    I have a 3-day old SIM-free iPhone 6s that I bought from Apple online. It's set up to display actual signal strength instead of dots (used field test mode to set it). In the span of a few minutes, the signal strength will be -75 dBm (5 dots) and then suddenly drop to -110 to -112 dBM (2 dots). My wife's iPhone 5 will show a constant -74 dBm that whole time. It will stay at -110 dBm until I toggle airplane mode on and off. I see lots of entries on a thread at apple discussions about this, but no resolution.

    1) Do any of you have the same problem?
    2) Is there a real fix?
    3) Do I have the same 14-day return window with Apple directly that others have buying through a carrier?

    The nearest Apple Store is 175 miles away, and our whole area is in the midst of an ice storm.
  2. WilliamG macrumors G3

    Mar 29, 2008
    Quite a different antenna system and LTE chipset. Try running and see how your speeds are.
  3. johnhurley macrumors 6502a


    Aug 29, 2011
    Try 9.2 beta 4?
  4. aKansasKid thread starter macrumors regular

    Apr 27, 2015
    Since my Verizon prepaid is capped at 5 down and 2 up, the -75 dBm connection speedtest ran at 5 down and 2 up. When the signal dropped to -110 dBm, the speedtest ran at 5 down and 0.4 up. I understand the radios and antennas are different from the 5 to the 6s model. I'm referring to the 6s itself suddenly dropping and staying there until I toggle the connection off and back on.
  5. aKansasKid thread starter macrumors regular

    Apr 27, 2015
    I first want to know if mine's an anomaly. Others on Apple discussion have reported it, but I can't find any mention of it previously on this forum.
  6. cynics macrumors G4

    Jan 8, 2012
    I get similar type of service with my 6S on Verizon however it was the same on my 5S so I don't pay attention too it. As long as it works is all I'm concerned with. I would be apprehensive if I were you too but like I mentioned my 5S was the same so I didn't really notice a change so I didnt worry about it....
  7. aKansasKid thread starter macrumors regular

    Apr 27, 2015
    Thanks, that's a little reassuring. I'm wondering, though, how much it's going to drop when I'm somewhere where the initial signal is less to begin with. Will it drop off to No Service? With all the ice, I'm homebound with this great signal for a while. ;)
  8. cynics macrumors G4

    Jan 8, 2012
    I don't have that problem. It fluctuates between high and low but RARELY no signal. The times its no service its because there is literally no signal.

    Keep in mind if you drop off Verizons LTE signal you'll fall back onto their 3g or even more dreadful 1x networks. But I find that to be relatively rare even in rural areas anymore.
  9. aKansasKid thread starter macrumors regular

    Apr 27, 2015
    I posted previously that my Verizon 6s would drop suddenly in signal strength at my house from, say, -78 dBm to -110 dBm, yet my wife's iPhone 5 would stay about -78 dBm. Using Field Test Mode, I was able to figure out that the 6s was switching between XLTE Band 4/1700 MHz and Verizon's older LTE Band 13/700 MHz. My Wife's iPhone 5 doesn't support Band 4, and thus stayed on Band 13.

    But why would the 6s switch to Band 4 when it was showing a much worse signal? Read on.

    Some technical articles explained that the measured RSSI, total received power across the bandwidth, is what shows on your phone if you exit while retaining the displayed signal strength instead of dots. But measured RSRP, the linear average power of the downlink channels' powers, is what your phone uses to manage tower handovers, selection, and reselection.

    Turns out that in my house, while the iPhone 5 is showing -78 dBm on Band 13 (as does the 6s when it's on Band 13) and while the 6s is showing -110 dBm on Band 4, they both are showing about -69 dBm for measured RSRP, fluctuating a few dBm. So I think what I see my 6s doing is switching between Band 13 and Band 4 based on higher RSRP, and I need to ignore the (RSSI) signal strength my phone shows when out of Field Test Mode.

    The downside is that while either Band 13 or Band 4 will yield the Page Plus capped 5 Mbps down, Band 13 will run uploads at the capped 2 Mbps, while Band 4 will upload at about 0.5 Mbps, at least at my house. But that's really not a bother to me since I'm on Wi-Fi at home anyway.

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