iPhone signal issues; is it to do with the frequency the network transmits on?

Discussion in 'iPhone' started by mrochester, Nov 16, 2010.

  1. mrochester macrumors 65816

    Joined:
    Feb 8, 2009
    #1
    Hi all

    I have both a Vodafone and T-Mobile sim that get pretty much the same signal in my house. Holding the phone 'normally', both sims will drop from 3G to 2G, but then the following difference is apparent; the Vodafone sim will continue to hang onto a fairly decent 2G signal, but the T-Mobile sim will drop to 'searching...' and then 'no service'.

    Looking into it I see that Vodafone primarily broadcast on the 900mhz frequency for 2G coverage whereas T-Mobile broadcast only on 1800mhz. My slight understanding of this technology is that the lower the frequency, the better the signal penetration. Could it be this that is causing the signal issue for many iPhone owners? I see that in the US AT&T broadcast on the 850mhz and 1900mhz frequencies which mirrors very closely my situation here in the UK.

    Has anyone got any thoughts on this?

    Ta!

    Michael.
     
  2. lucifiel macrumors 6502a

    lucifiel

    Joined:
    Nov 7, 2009
    Location:
    In your basement
    #2
    I'm not sure about the mechanics of signal attenuation and frequency, and of course your little demonstration can hardly be 'scientific', but I would love to hear why you think the lower the frequency, the better the penetration.
     
  3. Daveoc64 macrumors 601

    Joined:
    Jan 16, 2008
    Location:
    Bristol, UK
    #3
    Put simply, a lower frequency transmission (assuming that the power it is transmitted at and the location it is being transmitted from is the same in both cases) will travel further - both in distance, and through objects.
     
  4. Daveoc64 macrumors 601

    Joined:
    Jan 16, 2008
    Location:
    Bristol, UK
    #4
    What you have observed is correct. When you hold the iPhone 4 in certain ways, the signal is attenuated significantly.

    With some frequencies, the effect of that attenuation is more pronounced, simply because the signal is less resilient to begin with. Higher frequencies (like those that T-Mobile and Orange use) as well as 3G signals in Europe (2100MHz) are likely to see a more noticeable drop than lower frequencies (as used by O2 and Vodafone in some areas).
     
  5. joec1101 macrumors 6502

    Joined:
    Jun 29, 2010
    Location:
    So Cal, USA
    #5
    Yes, it definitely has to do with the frequency used.

    In a nutshell, the lower the frequency, the better the signal travels across the surface of the earth, primarily because the wavelength is larger. The higher frequencies don't travel as far. This is why GSM providers like ATT and T-Mobile have more dropped calls (they use higher frequencies). The solution is more cell towers, but that doesn't seem to happen fast enough anymore.

    In the early days of RF wireless communication before repeaters and cell towers existed, the lower frequencies were always used because they travel much better.
     
  6. Daveoc64 macrumors 601

    Joined:
    Jan 16, 2008
    Location:
    Bristol, UK
    #6
    That isn't correct.

    Verizon (just one example) uses the same frequencies as AT&T. Sprint also uses the same frequencies.

    GSM, UMTS, CDMA, AMPS etc. are all frequency independent.
     
  7. firewood macrumors 604

    Joined:
    Jul 29, 2003
    Location:
    Silicon Valley
    #7
    Diffraction. Effect varies according to wavelength. Physics 101C.
     
  8. ItsJustafnPhone macrumors 6502a

    Joined:
    Jul 26, 2010
    #8
    bunch of people with intro to physics classes trying to figure this all out

    it has a lot more to do than just the wavelength frequency


    signal power, antenna design ( whether it even accepts that frequency), tower saturation, weather, etc

    all of these factors could be affecting this so called experiment

    this is why I really like anechoic chamber testing is pretty valuable information (and yet still people spend $150+ on aluminum cases that destroy signal strength)
     
  9. joec1101 macrumors 6502

    Joined:
    Jun 29, 2010
    Location:
    So Cal, USA
    #9
    They do utilize both bands but the lower band (800 Mhz) is typically going to provide a stronger signal than the upper band (1900 Mhz). In this geographical area of the U.S., VZW and Sprint typically use more lower band for voice and ATT & T-Mobile typically use more upper band. So, it would make sense that VZW could have a better signal (in this area at least).
     

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