iPhone 4 antenna problems clarified (a bit)
Anandtech has done some testing to try and find out what's happening with iPhone 4 signal attenuation and related antenna reception problems, and come to two equal yet opposing conclusions:
Holding the iPhone 4 without a case, in your left hand, crossing the black strip can result in a worst case drop of 24 dBm in signal. [...] The fact of the matter is that either the most sensitive region of the antenna should have an insulative coating, or everyone should use a case. For a company that uses style heavily as a selling point, the latter isn't an option. And the former would require an unprecedented admission of fault on Apple's part.
And here's the flip-side:
iPhone 4 performs much better than the 3GS in situations where signal is very low, at -113 dBm (1 bar). Previously, dropping this low all but guaranteed that calls would drop, fail to be placed, and data would no longer be transacted at all. I can honestly say that I've never held onto so many calls and data simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so it's readily apparent that the new baseband hardware is much more sensitive compared to what was in the 3GS. The difference is that reception is massively better on the iPhone 4 in actual use.
Dieter is struggling with a lot of this while traveling back from the Samsung Galaxy S event in New York yesterday, what with AT&T's historic iPhone network problems and now this added uncertainty of how iPhone 4 is held has him speechless (in several ways).
We can put a case on it and hope for the best, or hope Apple will quickly push out an iOS 4.0.x update that alleviates it, but the layered and varied uncertainties surrounding what for many is their primary method of connecting and communicating is no doubt becoming untenable for some.
[Anandtech via When Will Apple?]
Editor-in-Chief of iMore, Executive Producer at Mobile Nations, co-host of Iterate and ZEN and TECH, cook, grappler, photon wrangler.
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Once again, a hardware failure design. And Apple can't admit this because people will return this thing in masses. Lawsuits, etc. I hope they make an iphone 4.5 pretty soon, my 3g is getting really dated and I will not settle for the 3gs or a badly produced iphone 4.
I'm confused -- Anandtech says "reception is massively better on the iPhone 4," but the graph says lower numbers are better, and the 3GS posts much lower signal attenuation numbers than both the iPhone 4 and the Nexus One, suggesting it's the best-performing model out of the three. Am I missing something?
Anandtech's results exactly mirror my real world performance. Without the case, I have serious signal loss when held naturally. With the case, there's no loss. And in areas (my office at work) where I just barely couldn't get a signal with my 3GS, I can now fairly reliably place calls on my iPhone 4.
I'm very keen on the conclusion that holding with any hand will cause a short circuit between the antennas which then causes the signal drop. When my hands are dry the signal drop is much smaller/slower than when my hands are sweaty. And anyone knows that sweaty hands are better conductors than dry hands.
Apple should just admit they never caught the failure due to their field tests using 3GS disguise cases which would always cover the antennas.
Come on, Apple! Be adult about it and admit that the problem is real!
Keith, if I understand correctly, eventhough the 3GS is less susceptible to attenuation, it has a weaker antenna to start with. Ie: when on a table, the 4 is better, but when held the 3GS might be better depending on how you're holding the phones and if theyre in cases.
My iPhone 4 currently is not transfering any data over 3G. It says I have 5 bars. I can text and call fine. When I try to use data it just spins it's wheels. I just restored as new and still nothing.
Apple can't recall the new iPhones. Apples stock price assumes apple can do know wrong. If they recalled nearly 2 million phones, the stock price would drop by 25-50%. They're much better off with "anecdotal" complaints and calling them a "non-issue". The only time you recall a product is if it's not safe, as those lawsuits are particularly expensive.
Also, like Keith, how are they saying the iPhone 4 is better than the 3GS? In that graph the 3GS is better in every category...
I remain unable to reproduce even the slightest signal drop in my home when holding my iPhone without a case. And its damn hot and muggy in the UK at the moment, sweaty palms agogo. And it definately has better signal than my old 3G in places like my local, which has historically been terrible for data on O2.
Its very odd. But not really a problem for me as I keep mine in a bumper-esque case anyway. its more comfortable for gaming that way. I'm really not convinced this is a big a problem as made out.
And as for lawsuits.... The phones only been out a week, return it. Problem solved.
Even with the reception issues, I haven't dropped one call yet. So there is definitely improvement in signal quality.
Even though I can't recreate the problem with mine, Apple should bite the bullet and allow everyone that has bought an iphone 4 to get a free bumper in the color of our choice! That would be sweet.
I returned mine this am. I asked the Apple guy if anyone else has been returning the phone and he quietly nodded yes to me. Now what to do. My 3G is too slow for me to live with much longer and I am out of contract with AT&T. Thinking about heading over to the Verizon store for a handset from the dark side. I am so disappointed.
Omar hasn't experienced one single reception issue with his IPhone 4, ya feel me?
@dantv im on my way to return mine now, did they charge you for restocking fee
What Anandtech means about the iPhone 4 being massively better then 3GS is when signal strength is very low (one bar). The 4 can still transmit data and voice well with a poor signal while they're saying the 3GS couldn't operate very well.
Still not sure if I'm trading in my 3G for this yet...
I was able to reproduce the bar-drop but I never had a call drop. I just bought an ifrogz Luxe Lean case - problem solved. I know people feel that they shouldn't need to buy a case but I would buy one anyway because I want to protect the phone. I can now grip the phone in a way that had caused the bar-drop and it's fine. So for me it's really a non-issue.
I am not sold my iPhone 4 has better reception than my 3GS did. My parents live in a fringe service area where I totally lose service at an exact location every time. My "4" loses service at the same location, but seems to start bottoming out much earlier. Nothing scientific, but just my own observations.
I just got this awesome black 32GB iPod Touch 4. What is cool about this latest iPod Touch model is that if I put a bumper on it, I can also make and receive telephone calls.
@Everyone,
What the article states is that the iPhone 4 (when held by human hands), will experience a significant loss in signal - lower than the 3GS. However, while the 4 takes a dive in signal strength - it is BETTER AT HOLDING ON TO THE LAST BIT(S) OF SIGNAL than the 3GS; and therefore BETTER AT HOLDING ON TO THE CALL/DATA TRANSFER. Hence, when the 3GS experiences signal reduction - it will simply drop the call or stop the data transfer. But the 4 is more likely to hold on the transmissions!
I got the phone on the day it came out. I can't get my phone to drop the bars. Is this every phone or just some phones?
@ dubbdee. Same here, I've never used any of my iphone without a case, very slippery and I'd break it in a matter of days...I noticed that when making calls with only one bar of reception i had no problems with the call quality...data slowed down a bit though.
RF is complicated, but I can pretty much guarantee that when you touch an antenna, you are going to affect signal strength, and affect it differently depending on how resistive you are at the moment, whether there is any capacitance between you and the antenna, and the frequency of the radio signal. So, if you took apart your iPhone 3G and touched its antenna, something would happen. You can't normally do that, which separates the two phones; you can attenuate the signal just by putting a body part near the antenna, though. That's why cellular phone instructions - like the Nokia ones thrown around - tell you not to cover the antenna with body parts.
In order to figure out what really is going on, we need a lot of information from the phone about what cells it is connecting to, what frequency bands it is using, how much signal attenuation there is, and what the phone itself is attempting to do when various things happen. None of this information is easy to obtain from the iPhone 4, so we are basically a bunch of blind men trying to figure out what animal we are touching.
As long as you can touch the antenna, you are going to influence the phone's radio performance. I guess that's bad design no matter how you look at it.
I would not be surprised if something about the iOS 4 software causes the phone to behave especially bad in certain cases where the cellular signal drops significantly, in certain combinations of cellular coverage (cell load, frequency bands). From that angle, hopefully Apple can do something to minimize problems when you do touch the antenna.
Proves my point. Even the craptacular nexus one has a big drop in signal. I swear people cant read. Let me put it in stupid english for the people that cant seem to get it:
ALL PHONES LOSE SIGNAL WHEN HELD
If you cant handle the truth then stop using a cell phone and go cry to your mommy.
Also, this is just an anecdote, but I used to have some free-with-plan Nokia phone which had an odd rubberized part on the back of the case. As far as I could tell, the bump with a dimple in it was intended for you to rest an extended finger in while you cupped the phone by the bottom. (Perhaps the antenna was up there, and it was old enough that the FCC wasn't encouraging companies to put antennae in the bottom away from the head?)
Holding it that way would definitely give me better reception, so I assumed the antenna was at the top and the bump was there to encourage you to hold it so you didn't cover it over.
Today I reactivated my 3GS and put the 4 on eBay. I love the phone but I can't touch it without it having reception issues. I made it lose data just by holding it.. This is how I hold my phone and I shouldn't have to use a case to make it work.
It's a ruse. Software upgrades will correct the problem in phases. The intent of fielding sub-standard performing hardware was to minimize the effects of increased subscribers. In other words, AT&T will dictate what regions are permitted full use of their iPhone based on the unused capacity of the underlying network. If you are in a congested area then you get to enjoy your shiny new iPod Touch 4 with limited data transaction capability.
How's that for a conspiracy theory. Regardless of the truth, this is only feasable in a non-competitive situation like the exclusivity agreement cretes. If multiple networks carried this thing then they would scramble to fix the problem. Such as it is, you get to hold your device differently. No one cares what you paid for it.
I'm not really biased. I enjoy my Apple, Andriod, and WebOS stuff pretty much equally.
I've read all the comments. Only two above are actually complaining. This seems to be a bit of a non-issue. I would expect to see hundreds of negative comments in this thread if it were a serious problem. Prove me wrong people!
Just get a dang case! Problem solved! Why does this have to be so difficult?
This issue has nothing to do with body tissue absorbing RF. The issue only occurs when you short out the transmitting GSM antenna at the bottom with the WiFi antenna on the left. It just so happens that many people's skin has just enough conductivity to short the antennas, but the same will happen if you short that bottom left seam with anything conductive like a key or coin.
To prove it, try the following (at your own risk of course, but several people have done this with no permanent ill effect including myself):
1) Carefully balance your naked phone on its right side on a wooden surface in an area where you get max signal and let it stay there without touching it for a minute to prove the signal is stable.
2) Get a bare metal coin or key and place it across the bottom left seam on the phone without otherwise touching the phone. Make sure the object is touching the metal of the phone antennas on either side of the seam, but do not hold on to the object.
3) Watch the signal meter for about a minute. It may take a little while for it to go down, but it eventually starts spiraling down for me, every time, even if I use my finger or palm of my hand instead of a coin.
4) Remove the object and watch the signal slowly ramp up again.
5) Repeat this for the seam on the right side (nothing happens for me)
I can also cup the entire bottom and right of the phone with my hand and it has no effect on the signal, so long as I do not touch that bottom left seam.
It isn't an issue for voice calls for me because I hold the phone to my right ear and never end up touching the bottom left seam. But when using 3G data I usually hold the phone in my left hand and operate with my right, so I often end up shorting that bottom left seam, which eventually kills the data connection.
Only Apple really knows what the signal meter is actually showing so we can only speculate as to what is happening internally, but it looks to me like the act of shorting the antennas is confusing the baseband firmware and is causing it to do the wrong thing resulting in a drop in signal.
This is why just putting about an inch of insulating tape over the bottom left seam can solve the issue. The reason why this doesn't always work is because some tape is conductive enough to trigger the problem when you press your skin against it.
If this cannot be fixed in software Apple should either offer a free bumper case and/or a free service to coat the bottom left part of the antennas in something that will not rub off easily like a clear epoxy.
Every iPhone 4 shipped with same software. But there could have been tiny differences between the hardware due to manufacturing tolerances. So the fact that it affects people on such drastically different levels suggest to me that it is a hardware issue.
@Loz and Kat Really? Just ignore and cover up a major defect? Nice answer. Hey everyone! Nevermind. Just hold it differently. If we ask nicely perhaps we'll get free bumper cases. Don't worry about quality standards.
I am still thinking this shorting only happens when SIM cards are not properly installed or defective... I think this is what happened at Foxconn, the Chicoms did not properly install the SIM cards. In test units with custom cut down units, this problem did notnexhibit itself! As for the Engadget article in this, they did not test it properly!
@sting7k
Have you tried calling AT&T? I had a problem a few weeks ago on my 3GS and thought it was ios4. It turned out AT&T "accidentally" turned off my data service. They did the same thing to a friend but turned off his text plan...
@everyone
Get a bumper or case and stop crying. If crying continues, then return the phone and go away. The dead horse has been beaten...
The real problem is the proximity sensor issue, which I believe will be fixed in the next software update
@Mac - Agreed! @Everyone else - Yes we all know getting a case/bumper will solve the issue! However, this isn't about getting a "band-aid". Your shiny new toy that costs hundreds of dollars has a major design flaw. And you as a consumer shouldn't have to spend extra $$$ to fix it! That's the point! Get it?
Stop crying? 599$ worth of cell phone shouldn't be expected to function without a protective case?
Besides, I don't remember seeing the "bumper" in any of the WWDC photos or videos. I just saw the iPhone. So if I decide to purchase the phone, the "bumper" shouldn't be forced to couple with my new phone just so it will work!
I live in a very poor reception area, and I can confirm I do get a slightly better signal overall with the iPhone4. I quite like the Bumper, but then I've always bought a case for my smartphones, the design may be lovely, but anything to protect it from an accidental meeting with the ground is vital.
You forgot to put that gently placing a finger on the black strip with hands that are naturally moist from human sweat glands causes all data/signal to fail.
http://gizmodo.com/5575347/video-clearly-shows-antenna-defect-on-iphone-4-web-browser
The dead horse will continue to be beaten as no one wants to get rid of their new iPhone as it makes them feel less cool. If a Droid had this issue, it would be returned, no questions ask. But the fan base cannot deal with parting with something they have pined for for so long.
For that reason, the dead horse beaters need to STFU.
@sting7k This might be a stupid question, but, are you sure the cellular data switch isn't toggles off? It's on the same page as the 3G network enable switch. Just a thought.
"Only Apple really knows what the signal meter is actually showing so we can only speculate as to what is happening internally, but it looks to me like the act of shorting the antennas is confusing the baseband firmware and is causing it to do the wrong thing resulting in a drop in signal."
If you RTFA then you will learn EXACTLY what it is showing
In straight up db readings in fact.
"If a Droid had this issue, it would be returned, no questions ask. But the fan base cannot deal with parting with something they have pined for for so long."
This issue was a big deal with the Nexus One, to name just one DROID that you are looking for. Google issued an update that made a few changes to how signal bars are displayed and a change to how the device decides to switch between 2g/3g and then issued a statement sayign that everyone should shut up about it. Eerily prescient of them to act like Apple before Apple could
.
I hope everyone reads the entire article. Anandtech really did an excellent job reviewing iphone 4 and dissecting the antenna issue. At the very least, Anandtech's research/theory is able to explain all the different accounts people have had with their antennas.
The bars on any phone is just a rough estimate of the signal quality. Anand was able to cleverly get the raw signal strength data of his iphone 4 (expressed from -51 dBm to more than -113 dBm with -51 dBm being the best signal you can get - very near a tower).
For example, a -51 dBm to -91 dBm rating is actually represented as five bars on the iphone while -113dBm is equivalent to a single bar.
Anand's testing and most iphone users' seems to agree that the iphone 4 is able to get better call reception than the 3gs if it has at least a single bar signal. The iphone 4's antenna is actually SUPERIOR to previous iphones and most probably to all phones in general due to the innovative external design.
The PROBLEM however is that it is more susceptible to signal attenuation/degradation also because of that design. Degradation is caused by the fact that humans are mostly composed of water and flesh which interferes with the antenna. Anand's data shows that the degradation is 50% to twice that of the Nexus One depending on the hand position (ALL PHONES experience attenuation).
The "death grip" generally results in a 20 dBm loss. What this means is that if you are in an area with good coverage (5 bars), you will not be affected by the antenna issue and most likely will NOT be able to force the signal to drop (-51 - 20 = -71 dBm, still represented as 5 bars).
HOWEVER, if you only have (to start with): 4 bars (-99 to 101 dBm) 3 bars ( around -103 dbm) 2 bars (around -107dbm) 1 bar (-113 dBm) than the "death grip" will most likely kill your reception.
Again, please just read the article as I'm not as articulate and smart as the two authors. To also put the issue into perspective, if you generally have good reception in your area and casually avoid touching the antenna than you won't have any problems.
Anand also pointed out that Apple can add another coating to the lower antenna part of the Iphone and tweak how the signal data is represented on the iphone in order to limit the problem (Again all phones have this limitation).
Better yet, Anand's testing with an iphone 4 in a case resulted in less attenuation than the Nexus One. A case will not only protect your iphone but the iphone 4 combined with a case will give you one of the best "phones" in the market.
(To be honest, I've never had call issues with my iphone 3gs, I guess I'm lucky)
@Loz: A non-issue? You're right nothing to see here folks...move along. You honestly think that everyone with this problem reads this blog and will comment? Good god some of you people are delusional.
@Zeagus: I did read the article. Anandtech are making an educated guess as to what the meter shows and they even said that it doesn't really show what is going on. Apple's source code is not available and as far as I know it is not specified precisely in any docs what calculations are performed to display the signal meter. Hence only Apple can really say what is going on, but they're being classically silent at the moment.
Cupping tightly.....snicker
@MrC -- Did you miss the part where Brian/Anand restored the hacked version of the settings file that made it display the DB readout and then the chart with the exact db ranges per bar?
Just get a case. GET A CASE! Sometimes things aren't perfect and you can either bitch and moan about it until the end of time, or take appropriate action and go on living your life. I know how much the phone cost you. I know it sucks that there's an issue. Now that the problem is known and the solution is known, continuing to drop calls is YOUR FAULT. While you're at it, go play in traffic...
I had my Iphone 4 a total of two days and returned it. If I can't make a 1/2 hour call without the call dropping 3 times then I want nothing to do with that device. The phone was sitting on the arm of the couch and I was using bluetooth during the call. That is just one example and the last straw.
It is 100% hardware issue. Let's not lose sight of the fact it has to a phone first.
I've also seen that some are thinking that it is the MicroSIM card which touches the SIM tray and causes a short. So maybe get Dieter to remove the SIM tray take the card out and reseat it see if that helps? I thought AT&T just finished their upgrade in NY??
@Fishcalls - If it was sitting on your couch untouched then it is not the issue being discussed here.
@iPheuria - the SIM stuff is conspiracy theory nonsense. Engadget posted about it this morning.
Well to keep talking about it is pointless. Let's just hope this is just a software issue because if it isn't this is major. I promise you I will not buy this phone until this is verified as the fix.
Last night, in the movie theater I had no bars with my ip4, my friend had all bars with her 3G! I even have a case on mine! Eventually the bars would come and go, all the while hers were always at full bars!! But I will deal with it, I'm not normally hanging out in movie theaters, I love my ip4 regardless of signal issues here and there!
I seem to have the issue with a case on. I am seriously considering returning this phone at this point. I am going to read the entire article and try reseating my sim card and see what happens.
also interesting to see how the signal on the Nexus One changes under the same conditions. Wow.
Got the iPhone 4 yesterday. I try n hold it in diff ways to see if I lose any signal and nope it's stays the same... Love this iPhone more then I did my 3G (sorry 3G)
Just go to apple and ask for one that's not affected. My phone works perfectly with or without a case. There are iPhone 4's out there that don't have any issues. I know that the supply will be short for the next while, but it never hurts to ask.
Everyone needs to read the article by Anand before posting a comment. The article is very clear and explains the antenna issue exactly. Blog are so frustrating to read, the future is grim here in north america.
Ime going to give all the people who are having trouble understanding RF signals and antennas some links, specifically when it comes to cell phones, so that you may stop hating on the iPhone4 and go find another something to whine about:
http://www.youtube.com/watch?v=O18yMX7Ee4I&feature=player_embedded
http://www.youtube.com/watch?v=eaDE941PzQk&feature=player_embedded
http://www.youtube.com/watch?v=x2g5J4qPp54&feature=player_embedded
http://www.youtube.com/watch?v=amPG52DVQuk&feature=player_embedded
So those were some examples, now go on over to Wiki and learn all about all the different subjects that are related to this, and start to relax knowing there are just many things in this world that are out of our control. Sigh:
http://en.wikipedia.org/wiki/Electrostatics http://en.wikipedia.org/wiki/Electricfield http://en.wikipedia.org/wiki/Mobilephone http://en.wikipedia.org/wiki/Radiointerference http://en.wikipedia.org/wiki/Bodycapacitance
And you can find mush more by doing a simple ggogle search.
Oh and I'd be more worried about the radiation and cellular damage being done TO your body then the loss of signal to a phone BY your body.
Please everyone go read this blog.. first two articles... someone finally makes sense and thus should shutup the haters.
http://www.antennasys.com/antennasys-blog/
I'm not having antenna problems, but I AM having "phantom" dialing issues when I have the phone to my ear during a call, I guess the screen turns on and I'll inadvertently hit various buttons, called my granny at 2am
woops, that and sometimes when I hit the volume button my iPod switches songs.. Weird.. Has anyone had any of these issues? Is the glass making it too sensitive? I would return it, but I already sold my 3G... 
so, this just proves that AT&T was never really at fault (except for where everyone, not just iPhone users, had problems).
Simply amazing. You know I think that Apple is facing all of these issues because they rushed to make the iPhone 4. Android more than likely caused this. However, Steve needs to give an official statement and soon. Until then we can only speculate.
Any how theres this article at http://getyourgadgetsgoing.com/ called "iPhone 4 Is In But The Problems Are Out: Complete Overview"
Check it out for the complete listing of iPhone 4 issues and one that you may yet have heard of but still might be experiencing.