The so-called 'death grip' effect, in which a user's hand touching a smartphone antenna degrades its radio connections - a major issue for the iPhone 4 with its external antennae - is real and is a serious problem, according to British boffins researching the matter. Furthermore they found that plastic insulation between hand …
Why just blame the iPhone?
I'm no Apple fanboi but surely these findings affects all phones, if making a connection between your hand and the antennae, even through a plastic barrier, degrades the signal.
Because I presume the distance is important - even an extra couple of mm can have a huge effect, most other phones bury their antenna a bit more deeply than the iPhone.
I'm a rabid Android fanboi, but even I admit that holding my Nexus One in certain places seems to have an effect on the signal.
Maybe the "hand-making-a-bridge" problem was more noticable than the problem tested here though, which would explain why the bumper cases have helped.
In the article
It mentioned that smartphones were bad, but when the antenna is actually touchable (i.e. iPhone) it's worse.
At least that's how I read it.
Why does the iPhone 4 get a signal in places where my old Motorola didn't (just a week or so before)?
The thing about the iPhone 4's antenna design is the "weak spot" is marked with other "traditional" designs there is a "weak spot" but it hasn't got a line showing you where it is!
Now the iPhone 4's design isn't perfect, the thing is a bit "slippery", especially with glass on both back and front, but I don't think raw "network coverage" is really an issue - mine seems to find a signal in places where both Nokia and Motorola handsets didn't. Yes, we're talking about the same network.
No I don't use a case with the iPhone 4, and it's just "stock" not modified or weird (or white!)
What is really impressive is the battery life (for a smartphone). Putting the antenna assembly in the phone's main structural element does make room for a bigger battery.
so you can spend far more time when you cant make a call runiing all them there apps.
it's a PHONE for fucks sake. that, under certain circumstances, cant make calls - due to crappy design. The words teapot and chocolate come to mind.
having a biger battery is irelevant
To quote Snatch
"Yeah Dad, you told us"
His next project is finding a catholic in the Vatican.
This is the first step
This is the first step of such a project.
It may be that the results don't come as a surprise, but in order to gauge the problem, you need to perform controlled, scientific tests.
The next stage, which he has said he will be doing, is to find a way round the problem. This is much easier when you have accurate measurements to start with.
That may be harder than you think
As most of the actual Catholics are outside waiting to see the Pope. Those who have risen far enough up the power structure of the church to be in the Vatican in uniform on the other hand have got there not through being good Catholics but by being good politicians.
You are assuming that Apple can not and has not already chosen the best compromise to deal with this? Apple just slapped an antenna on the outside then said "oh that's why nobody else does that". Apple thinks more than any other company about what makes a plesant experience for it's customers. This design isn't a "mistake". It's a carefully considered compromise between phone size and reception. Apple isn't perfect but they also aren't sloppy when it comes to product design.
Hardly "original" research
Scientific research to establish that the presence of a large conducting body near an antenna will detune it or cause it to be mismatched to the characteristic impedance of the feeder ???
I think you might well find a large, if not massive, body of research showing this. Stretching back a good few decades, if not to the birth of RF Communications (well, post-spark transmitters anyways).
This is why MIMO doesn't work as well as it might - one antenna impacts on the performance of the other.
"I think you might well find a large, if not massive,
body of research showing this."
Not to mention high-school physics. Fashion designers trumping engineers will always end in tears.
The general principle is not what was researched here. What was researched here was the specific effect under specific conditions.
We've known F=ma since before the invention of the automobile, but it wasn't until tests showed the results of application of that principle under highway collision conditions that auto manufacturers started thinking seriously about safety features.
No, that can't be real! Somebody doing
Stop the presses! Hell hath frozen over.
"Apple isn't perfect but they also aren't sloppy when it comes to product design."
I see you must not have used the new iPod nano (6th gen) for any length of time, then. That "hold" button is a disaster.
"Apple isn't perfect but they also aren't sloppy when it comes to product design."
As much as it amuses me to read the your wild speculations about Apple I must point out that the FACTS point to an altogether different conclusion.
working on “automated re-tuning of the antenna elements"
Why bother? let Apple fix it, it's their mess and they have much more money in the bank to pump into research
Yeah ... I'm sure they will 'fix' it ...
IF de-tuning detected THEN increase signal bars shown
...measuring it wrong. Not that big of a deal.
The opposite is true - Im no Fanboi
Past experienes with Portable radio suggest that touching the antennae improves the reception when signal is flaky. So why is it different here?
@opposite is true
There is no simple answer (as you might have guessed) as you have a number of conflicting aspects to antenna design.
In general, if you are talking about an electrically small antenna (i.e. physically much less than 1/4 wavelength, etc) then you might find that adding your fleshy touch improves reception by adding to the area able to intercept signals.
However, the converse aspect also applies (probably here), in order to make any antenna work efficiently they are normally in resonance (i.e. tuned to a specific narrow range of frequencies) and by touching them you de-tune them and so make the job of getting power in/out of them more difficult. In addition, the body is not a *good* conductor, so tends to make the thing lossy and not only to re-tune it to a different frequency.
Over all I expect flesh decreases reception.
The iPhone problem is certainly *not* unique, just that the close proximity of the antenna to the hand makes the effect significantly stronger, and on top you have Apple's attitude to the problem with their high-end device where style has prevailed over best-practice RF engineering.
I stil laugh at Jeremy Clarkson when he does the 'hold car key to head then open doors' thing on a much repeated Top Gear.
Maybe the iPhone needs to be placed somewhere else?
(ducks and runs)
Yeah that is it
Apple put the antenna on the outside, did some minor testing and told Steve that there could be a reception problem. Then Steve said who cares it looks cool this way. Yeah I see that happening.
The conductivity of skin to stainless steel is so low it can be discounted. What is more likely is you're creating a capacitance, but any antenna reasonably close to a plastic case would have the same effect (and in fact this appears to be true as the issue isn't unique to the iPhone 4).
Where the iPhone 4 is different is the spot where this is most likely to happen has a line across it. So if you want to demonstrate is then it's quite easy (cover the line with a finger). Conversely if you want to avoid the issue then don't put your fingers over the line (hence the much quoted; "you're holding it wrong"). However such spots exist on other phones too, they just aren't as clearly marked ;-)
The key bit being
"...Apple's attitude to the problem with their high-end device where style has prevailed over best-practice RF engineering."
If Apple had owned up to it whether saying it was a design flaw or a design decision, the flameage would not have been as intense. Granted saying design flaw would probably have been more expensive as people would then have expected them to FIX the design and retrofit it to all the devices already sold, but it would have reduced flameage.
Not spent any time in the field of RF design then?
At some wavelengths and in certain circumstances touching an antenna can result in an increased ground plane effect which might improve reception.
That's not true for UHF or microwave.
The issue here is that the finger bridges two different antennas creating a new hybrid metal/person/metal antenna that is severely compromised for any of its intended uses.
"Holding a phone degrades the signal"
Wow, wouldn't have guessed. Holding ANY phone degrades the signal - I see it on my iphone 3gs + 4, also on my ancient nokia dumbphone and my wife's new nokia dumbphone.
And the bumper: it's there to prevent the antenna bridging, and works brilliantly. With my iphone 4, I can kill the connection most of the time by holding it tightly. With a case, the effect is minimal (no worse than the other phones anyway).
Can I get a large research grant for typing that please?
Thinking you are clever is a symptom of stupidity.
"no worse than the other phones anyway"
You people keep saying that even though it is totally and utterly wrong.
While all phones may have a reduced signal in certain circumstances, the iPhone 4 has a special, additional problem all of it's own. That is what this research is saying.
No one is going to give a grant to person who has difficulty comprehending basic information.
"And the bumper: it's there to prevent the antenna bridging"
No. It's sold as insurance against the 4's well documented reception problems not specifically to prevent "antenna bridging". Look like it doesn't work.
unnatural laboratory situation
"then with the antenna actually in contact with a "thumb phantom" with the same dielectric properties as human skin."
So they didn't actually test it with an actual human thumb attached to an actual human person? How then can any reliable conclusions be reached? All they've demonstrated is antenna performance in an unnatural laboratory situation that assumes their replacement mimics all the variables of the real-life scenario.
They can say that the "phantom thumb" mimics the human thumb, but without a comparison performed in the same experiment how do they know? It's an assumption that may not be true.
Impressive selective reading there:
"reduction in sensitivity of the device when held, or when the user’s thumb is mimicked by phantom material"
RDF induced fact blindness.
It's quite a common ailment amongst fanboys.
No doubt someone will also attempt to explain how holding the precious while using it with no measurement equipment other than the reception bars is far superior to controlled conditions in a lab performed by an expert in the field.
Never mind guys.. Tell us again about the market cap..
"Holding The Precious"
You owe me one, buddy!
How do you know he's a fanboy?
He might just be thick.
'How do you know he's a fanboy?'
'He might just be thick.'
They aren't usually mutually exclusive...
Selective indeed. If you read what it says, the whole point of the experiment was to see what the difference a "bumper" made. Which they did not test with a real thumb or real hand or real person.
The test you are referring to was when the phone was held to demonstrated that it "reduced sensitivity" of the antenna. Which is not news to anyone, and wasn't the point of the experiment.
"'How do you know he's a fanboy?'
'He might just be thick.'
They aren't usually mutually exclusive..."
In fact they show a correlation constant that quickly approaches 1.
You'd think I would notice...
... if my iPhone 4 was 100 times less sensitive to GSM/3G/WiFi signals when I held it!
But I haven't. It's not even slightly less usable.
@I would notice
"if my iPhone 4 was 100 times less sensitive"
You forget that 100 times is 20dB, a big but not catastrophic difference to something like a mobile phone.
True that in free space it would represent a 10 time difference in distance, but in most mobile situations (e.g. in a city) you are pretty close to the base station and the phone can adjust its power to compensate, probably by over 20dB, so you see little effect on operation just a shorter battery life.
So you tend to get dropped calls when the network is busy and/or where you are further from the base station (but still in the nominal coverage zone).
Not at all odd
Apple design products for their known fanbase. Accommodating people with an opposable thumb is therefore not required.
Not odd at all.
One of the chacteristics of 3G/GSM phones is that they (and the base station) adjust the power required to the minimum necessary, to limit interference and save battery life. Faced with a poor antenna, the phone will just blast out more signal. It would only be in situations where the signal is already poor that you'd actually see problems, dropped calls, etc.
Go look up on wikipedia about decibels and then come back.
No reduction in signal will make it any less usable until it stops working. The point is that the amount of degradation and the method in which it is introduced means that point will be reached sooner than with other phones.
Yes we knew this
I think the conclusion was that even with the antenna detuning the iPhone 4 had better reception than the iPhone 3.
And if a bumper does not help then why not expose the antenna rather than sticking it just inside the plastic case like most smartphone do? Then iPhone 4 with a bumper is exactly like the iPhone 1-3 antenna placement wise.
My own experience with the iPhone 2 and iPhone 4 is that I get a little better reception with the iPhone 4. I use a bumper for glass protection but will probably remove it after a year or so when the phone isn't so shiny.
They knew this 68 years ago in the desert
Way back when Montgomery was chasing Rommel around the deserts of North Africa, the tanks had No. 19 sets which had an HF (High Frequency) main transmitter/receiver and a UHF transmitter/receiver compromising, I think, only one or two valves (tubes in North America) - the oscillator was also the 'power' amplifier, the other tube being the FM modulator. (See: < https://secure.wikimedia.org/wikipedia/en/wiki/Wireless_Set_No._19 >. The UHF unit is next to the power supply connector).
Apart from the tanks in the desert disrupting UHF transmissions in the UK (really), these UHF units could also be detuned off the operating frequency by grabbing the short antenna.
But I guess the Apple antenna specialists are more interested in re-inventing the wheel. Even square ones.
Grabbing the antenna of a high-powered field radio can often impair the performance of the soldier quite drasticly, and is not to be recommended.
Oh hell yes.
"Just hold this a minute", he said. I tell you, a 100w rig being keyed up is as effective as a cattleprod for various assorted bastardry.
...and the never-healing RF burn will serve as a constant reminder of your 100w japes.
If I recall from my days in the Royal Signals ...
these UHF sets were just for squadron inter-tank chat and had a power level of under one-quarter watt.
I never heard of anyone dying, or even getting burned, by grabbing a quarter-wave dipole.
The desert UHF sets jamming the assembly areas for D Day in the UK were due purely to 'skip'. These days 'skip' signals can't be heard because of the traffic carried on UHF.
no real surprise
No real surprise, really.
Anyone who has messed around with radio antennas knows that you can receive some rather strange results. Even today's digital TV signals present some very interesting situations. Such as the orientation of a LCD monitor some feet away from either the TV or the antenna. It changes the reflected signal. And at marginal receptive times, the effectiveness of the antenna can be observed. Some have even claimed that getting up to take a break affects the signal. No doubt it can happen.
Touching the antenna does detune it. And being nearby can do so as well.
Surely this can affect any handheld device. You have a big bag of mostly water so near the antenna. And that can affect the signal.
Only an idiot would design an antenna that in normal use is being touched by the user. Holding it just so probably helps. But, it is a bad design decision. Would you buy a car that heads into the ditch if you do not hold the steering wheel just right?
@Lewis Mettler: all cars are *designed* to head into the ditch if you do not hold the steering wheel just right (take your hands off the wheel and feel the drift)......it's better to head ditchwards than oncoming trafficwards
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