Some clues as to what is causing the signal issue

Discussion in 'iPhone' started by ArosaMike, Jun 29, 2010.

  1. ArosaMike macrumors newbie

    Jun 15, 2010
    So, I'm an engineer, and a collegue of mine has a friend (tedious link I know!) who works for a mobile phone manufacturer as an engineer. His take on the whole atenna issue is the following:

    1. Sticking your hand over the join between the atennae short circuits them (we all knew this!)

    2. The short circuit causes the two small antennae to form one much larger one (obvious I know...bear with me!)

    3. This larger antenna has a different frequency to the small one.

    4. The phone detects this and switches between frequencies.

    Sounds simple in practice, but apparently it takes an age for the software to switch between the two frequencies. My guess would be this is to prevent the phone from hunting between signals. This could indeed be what Apple were talking about when they mentioned that the new phone placed lower demands on the network.

    For the sake of making things easy to understand, have a read through the two artciles on Wikipedia and HowStuffWorks:

    Basically, a Cell Tower has a finite number of frequencies it can use and assigns your phone to one of these frequencies. As you move around however, you'll be assigned different frequencies on different towers depending on what's available. As you can imagine, if a phone is super sensitive to variations in signal quality, it can reach a point where it jumps continuously between cell towers, placing high demand on all the switching hardware in the network. In reality, the user wouldn't notice any change in call quality if it stayed on one tower. By placing a delay in the frequency switching on the phone, your call will no longer be shuffled around towers constantly and will instead stick to one cell tower for longer, reducing the amount of juggling the network servers have to do and hence reducing dropped calls.

    Here in lies the problem. When you change the length of the antenna on the phone, you cut out it's ability to see one segment of frequencies. The phone then starts looking for another available frequency. This now takes forever. Although the frequency may well be avaible, by the time it's found it, the call has been dropped as the slightly weaking signal it is expecting as you move away from the original tower has completely dissapeared.

    The design of the antenna is undoubtably a fundamental design issue, which has somehow been overlooked or ignored. Let's not get into the politics of that here. What this does highlight however is that, if the delay between frequency switching is removed, reduced or in some way made smarter, the switch will be so quick, it won't have any noticeable effect on your call as it will just be another frequency switch similar to that between a towers.

    Discuss :p
  2. Slip Jigs macrumors 6502a

    Feb 18, 2008
    So you should be able to bridge the gap with a short piece of wire and realize the same effect, no?
  3. ArosaMike thread starter macrumors newbie

    Jun 15, 2010
    Yes exactly! Just tried I myself and it has the same effect as bridging it with my hand.

    Basically, it should, in theory be possible to fix the issue with a differed update, however, it will probably put more load back on the cell towers. Something with ATT probably want to avoid in the states. I suspect it's less of a problem here in the UK where our network is pretty good. We shall have to see whether Apple do release anything!
  4. Slip Jigs macrumors 6502a

    Feb 18, 2008
    I'd like to see a video of this, or any other way to re create the issue other than the grip.

    I think that's been overlooked in all the testing and debate.
  5. dmelgar macrumors 68000

    Apr 29, 2005
    You had me until the frequency switching.
    There's no indication nor evidence to support the statement that the iPhone is slow switching frequencies.

    And I think you're fundamentally confused regarding frequencies.
    Touching the antenna can drastically change its reception characteristics and make it better tuned to different frequencies as you said.

    But the phone does not typically switch between drastically different frequencies. It switches between channels which share very close to the same frequency.

    Carriers sometimes support more than one frequency, but rarely in the same area.

    As an example, AT&T in the US uses 850 and 1900 mhz for GSM (voice).

    My theory is that when touching the antenna, only one of the frequencies becomes harder to receive. When the iPhone is in the bad sensitive frequency location, it loses coverage. But if its in the other frequency range, it is relatively unaffected.
  6. army91c macrumors 6502a

    Mar 9, 2009
    Dude.... lots of people a hell of a lot smarter than you (and your friend) already know what the "issues" are and what causes it/them. IF you and your friend are such masters in your field, I'm sure apple would of consulted with you guys before releasing their final design. Did you get a call?
  7. bova80 macrumors 6502a

    Jul 8, 2008
    Pittsburgh, PA
    but why when i put a few layers of electrical tape there does it still happen?
  8. Slip Jigs macrumors 6502a

    Feb 18, 2008
    That makes sense also.

    My crackpot theory is that these frequencies/channels are somehow the same or related to the signal noise that we sometimes hear when placing an AT&T phone too close to speakers. I've noticed this with all my Cingular and then AT&T phones, somewhat not as bad with iPhones.

    I know know what it means, I just there's a connection.
  9. tigres macrumors 68040


    Aug 31, 2007
    Land of the Free-Waiting for Term Limits
    Does this theory in any way represent the time it takes now to connect a call? When I dial on iP4, the call takes between 5-8 seconds to ring- never on my 3GS.
  10. dmelgar macrumors 68000

    Apr 29, 2005
    If Apple was so smart, they never would have released a phone with this issue.
  11. brentsg macrumors 68040

    Oct 15, 2008

    Seriously.. how do you make the determination that one particular set of random internet people were smarter than some others?

    Did these other random internet people get a call from Apple?
  12. Slip Jigs macrumors 6502a

    Feb 18, 2008
    Good point. Now that you mention it, I've noticed the same thing.
  13. brentsg macrumors 68040

    Oct 15, 2008
    You're probably too young to have messed with getting decent TV reception with the old rabbit ear antennas.

    You could walk up and monkey with the antenna until you had the perfect reception. Then as long as you were standing close to the TV everything was great. But if you walked away, sometimes it messed up the reception.

    Bottom line, you don't necessarily have to touch an antenna to change its performance.
  14. bova80 macrumors 6502a

    Jul 8, 2008
    Pittsburgh, PA
    thats what i figured. cause i know when playing with fm antenna's when you touch them you can get clear reception then you let go and it gets fuzzy again. so i figured as long as you are close it would have a problem. i even tried making my finger into a hook so i touched higher on one side of the line and lower on the other and it didn't have the issue. so the tip of my finger and base of my finger were about an inch apart. does the bridge have to be with a central part of your finger?
  15. army91c macrumors 6502a

    Mar 9, 2009
    What issue? I have no issue. I can hold it over all 3 breaks in the antenna without issue.

    Very easily.
  16. hwalker84 macrumors member

    Jun 23, 2010
    That would make sense if the issue wasn't still around with my bumper.
  17. ArosaMike thread starter macrumors newbie

    Jun 15, 2010
    Thankyou....I think you probably understand the mechanics of it all a lot better than I do! What I wrote was 3rd hand info mixed with some pretty quick research and some of my own musings which seemed to me some sort of sense.

    I would say that what you've described is what my colleagues friend was probably on about. But basically, he was suggesting that there is some sort of software 'fudge' that may help the problem, but fundamentally he thought it can't really be properly 'fixed' per se as it's a hardware issue. Whilst they may be able to fix the loss of connection, what you won't see is it switching channels to counteract the change of antenna characteristics.

    I appreciate your unnecessarily augmentative post is intended to invoke some sort of uneducated and angry response from instead I shall actually take the time to answer the 'questions' hidden in there with the reason and intellect you left out!

    My musings here are just that. I'm not claiming to be an expert in cell tech in any way. It was instead, the knowledge and opinion of one phone engineer, passed through to me (an Automotive Design Engineer) via another Automotive Design Engineer. I don't claim in any way to understand in depth how cell networks work, but I do know some fundamentals of the physics of antennae and radio communication. My colleagues friend is, however an expert in this area so, despite my obvious misunderstanding of the issue, there is some element of truth in it...and before you, Apple didn't phone him. But then considering there is rarely one 'expert' in any particular engineering field, it would be rather strange as to why they would anyway. Apple no doubt hired many experienced telecom engineers when they designed the iPhone. Whether they have priority over the team run by Jonny Ive however is a different matter.

    Design and engineering is always a compromise. One will always play off the other. I'm sure Apple may have been aware of the issue, but simulating real life use of millions of phones using a handful of prototypes in a handful of locations means that some apparently obvious issues can be totally missed. In their testing, the drop off in performance may well have been so miniscule, it was deemed (quite rightly) a lower priority to the aesthetics of the unit. Would they have sold 1.7million phones at launch if it had a 1ft long antenna shrouded in plastic sticking out of the side? An exaggeration admittedly, but some performance is always compromised for visual appeal, no matter what product you care to mention.

    Perhaps next your oafish and immature comments for some other place and you might learn something from the subsequent posts of others! This is how the human race has progressed to to the stage it is at and how myself and 15 other people design motorbikes, and Jonny Ive and several hundred others design an iPhone, a MacBook Pro and a load of corresponding software.

    If you want instead to spend your time insulting others, go and become a politician!
  18. Daveoc64 macrumors 601

    Jan 16, 2008
    Bristol, UK
    The testing that people have done rules that out (i.e. by testing locations where you can tell what frequency the signals being received are).

    Some networks with the iPhone 4 only use one frequency, so they're going to have to sort that out or those carriers aren't going to be happy.
  19. sleyeu macrumors 6502

    Oct 18, 2009
    You see i'm an Electronics Engineer as well (not for apple) and i think that Apple may have overlooked testing it in rural areas or areas with lower signals as Apple is based in a city. Cities normally have good reception everywhere.

    On the other hand I am an Antenna Engineer and I think that the antenna is fine. But i am also a scientist, who tests the conduction of human skin with electronic devices, which is why I am an Engineer for touch screen devices.

    Either way, i love this new iPod Touch 4g.
  20. daninfamous macrumors newbie

    Jun 29, 2010
    I was super paranoid about the signal/atenna issue, the guy that got the phone right infront of me, you barely touch that area and wam, signal gone.

    my phone, came in the att store at the 1030 shipment (had to come back, was 1st person to miss 7am stock) can be held anywhere, anyhow and no signal loss,

    so.. its not every phone.

    all im saying, not going to argue it or anything, just adding my info to the pool of knowledge.
  21. rotobadger macrumors 65816


    Sep 18, 2007
    Fantastic reply. Well thought out, reasoned and sober. Likely lost on the person for which it was intended however.
  22. ArosaMike thread starter macrumors newbie

    Jun 15, 2010
    Why thankyou....I suppose I can hope it'll make one more troll re-consider his time wasting I had a spare 5 minutes to reply ;)
  23. rainmanbk macrumors 6502


    Jan 30, 2006
    Southington, CT
    Dude calm down. The OP is just trying to explain things, maybe explore options, and give all of us a reason to believe this will or will not be fixed. He never claimed to be the smartest person alive, he was just sharing knowledge.

    What is up with people who don't care, posting?
  24. spiritlevel macrumors 6502

    Nov 5, 2007
    Sorry to be the bearer of bad news, but yes you do. EVERYONE has the issue. Some people just haven't been to an area where they notice it yet... Many people who originally posted to say there phone was fine are now posting saying that they went somewhere new and there phone started playing up.

    There are no "good" and "bad" batches of iPhone 4s. In many locations, they are ALL bad.

    No-one has yet been able to provide any evidence of 2 IP4s behaving differently (1 with the problem, 1 without) in the same location. They will either all exhibit the issue, or all be fine, in any particular place.

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