Antenna guru: 'Get a bumper and learn the Vulcan iPhone Pinch'
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Editor’s Note: The following article is reprinted from Network World.
“The public will be more ‘antenna-aware’: that’s the good thing to come out of this. They’ll walk into an AT&T store and say ‘lemme see that pink phone and what kind of antenna does it have?’ That hasn’t happened since we bragged about our newest rabbit-ears [antenna] for our old TV sets.”—Spencer Webb, president of AntennaSys, an antenna design and consulting firm, on the iPhone 4 antenna imbroglio.
Spencer Web isn’t exactly the Susan Boyle of antenna technology, but he’s experienced something of her Internet celebrity effect over the past week or so. He wasn’t well known outside of a pretty small circle, which includes what he calls his “nerd friends.” Then after talking to a reporter who called him to get some expert opinion about signal reception complaints for Apple’s just-released iPhone 4, he decided to blog about it.
Literally overnight, the daily unique visitors to his modest AntennaSys Website jumped from about 11 (as in “eleven”) to 89,000.
“It was a bit of a shock,” he says.
Since then, Webb has done a series of online posts that are a rare combination of lucidity and wit to unravel for those visitors the arcane mysteries of RF, antennas and the iPhone 4 reception issue. But he admits that he still has no answer to the question: “What were they thinking?”
Webb got his start as an analog design engineer, a task at which he was “merely adequate,” he says. He was also a ham radio operator and as he was constantly fiddling with the antenna, he decided to learn about them. “One day, I woke up and I ‘got’ it,” he says. Since that fateful dawn, he launched his own custom antenna design and consulting firm, based in Pelham, N.H. Besides extensive design and consulting work on embedded antennas, he has also worked for law enforcement and intelligence organizations operating with small battery operated devices…not unlike today’s cell phones.
But Apple CEO Steve Jobs did not call him to consult about the iPhone 4 antenna design. Apple will hold a press conference Friday at 10 a.m. PT, during which executives are expected to discuss the antenna issue.
Follow Macworld’s coverage of Apple’s press conference
We talked with Webb on Thursday, via his brand-spanking-new iPhone 4 (replacing an original 2G iPhone), complete with rubberized bumper ($29 via Apple) and what he calls the “Vulcan iPhone Pinch” or VIP (holding the phone between thumb and first two fingers, with remaining two fingers lifted off the phone)
NW: You saw the keynote speech by Steve Jobs, introducing the iPhone 4, and he called attention to the antenna design. What was your reaction?
Webb: It was instant. “They’ve got a problem.” I said in one blog post something like “if you had come to AntennaSys and said, ‘We’d like to put the antennas in the place with the highest probability of being covered with a hand!’, I would have tried to talk you out of it and find a better solution.”
NW: So… what were they thinking?
Webb: I ask that question with just a single question mark not several exclamation points. It’s not an “error” [by Apple]. I have designed antennas on devices that get implanted in the human body. The point is…you can design an antenna to take into account the body’s ‘loading effect’ on the antenna. But having that work and [also] having it work just lying on a desk are two very different problems.
In antenna design, you can think of a triangle with three labeled points: size, bandwidth and efficiency. We say “pick any two.”You can have an antenna that’s efficient and broadband, but then it can’t be small. The problem is the iPhone wants all three of them.
NW: So what are the options, in general terms?
Webb: You can design an antenna that changes itself—a smart antenna. Or you can design a very broadband antenna.
Smart antennas require [extra] space: you have multiple elements and electronics to handle switching between the elements or tuning the antenna. But in the iPhone 4, you can’t even drop a crumb in there. So that’s going to tug on the product design requirements.
If you have a broadband antenna, and it gets detuned, it wouldn’t hurt it. But broadband antennas are not small.
NW: So how would you do it?
Webb: I was thinking about that: what would I do? ‘If I screwed up this antenna, here’s how I would do it!’
The first step is—and I just know the Apple antenna guy [apparently Ruben Caballero, who warned Apple execs about possible problems, according to one news story did exactly this—I would go to the marketing dudes (this is California so you have to say ‘dudes’) and I would say, “Dudes, give me a piece of foam or plastic that is the shape and size of what you want to sell.” Then, I’d come up with some ways to put an antenna into this thing, when a human is holding it. The last place you’d put it is on the edges [of the phone]. The edges are always, always where you’re going to put your hand. All. The. Time.
But I don’t know what I’d do next.
NW: Apple said in its initial response to the complaints that signal attention is a fact for any cell phone.
Webb: And they’re right. [That happens] when a human hand is put over an antenna in any device. Period. I have a GPS from Garmin, for my bike. If you put your hand over the antenna, you stop receiving the GPS signal. That’s not new. Prior to my first iPhone, I had a Palm Treo, with a little antenna bump at the top. You just intuitively know if you stuck your hand over it, it wouldn’t work as well.
With today’s monolith [designs], we don’t want to admit there’s an antenna inside. I picture myself standing at Union Square in New York shouting, “it’s a radio! It needs its antenna!”
NW: Do you think people are rediscovering their antenna intuition?
Webb: My plumber handed me a [Motorola] Droid X [newspaper] ad. It says, “And most importantly, it comes with a double antenna design. The kind that allows you to hold the phone any way you like….” Now they’re boasting about their antenna!
The public will be more ‘antenna-aware’: that’s the good thing to come out of this. They’ll walk into an AT&T store and say ‘lemme see that pink phone and what kind of antenna does it have?’ That hasn’t happened since we bragged about our newest rabbit-ears [antenna] for our old TV sets.
NW: With your fellow “nerd engineer” and friend, Steve Golson, you devised a series of tests to measure the effect of different grips on the upload and download data rates for both iPhone 4 and iPhone 3G, measuring with a “naked” iPhone 4 and then with the same phone clothed in a bumper. Both phones were affected by touching, but the naked iPhone 4 showed dramatic drops in both upload and down data rates.
Webb: When we finally got around to the testing, Steve was doing the various grips. When he did the full grip, he looked over at me and said. “Oh yeah: this is making a huge difference.”We immediately saw that the full grip on the naked iPhone 4 was having a big impact.
A lot of this [controversy] was based initially on just staring at the [signal] bars. Apple took away or hid the ‘secret’ utility on the phone that would give accurate signal strength data. But data rates are a very smooth measurement, and it’s indirectly related to the Bit Error Rate. It’s almost as good as having a real BER measurement.
NW: So the “five bars”…
Webb: That was Apple’s smokescreen. The bars show what’s called ‘relative signal strength indicator.’ I’ll tell you what RSSI means. It means, “more is better and less is less better.” That’s all it tells you. With five bars, you know you can use your phone and life is good. With just one stinking bar, you know you might have problems….And they’re controlled by Apple: they say what Apple wants them to say. Staring at the bars is utterly useless.
NW: But the detuning of the iPhone 4 antenna, even as severe as your data rate measures show, actually might not be a problem in many cases, correct?
Webb: A voice channel is something like 60 kilobits per second. I can’t remember exactly. We were seeing 2 to 3 Mbps download speeds [in our test]. So it may not be a problem. You can degrade the channel by an awful lot and still have a decent enough Bit Error Rate in a 60-kilobit channel that you won’t know it on a voice call.
Consumer Reports said “we made this drop by 20dB and that can cause a dropped call.” But even [a loss of] 1dB can do that.
NW: The Wi-Fi and Bluetooth antenna runs from around the top left corner, over the top and down the right side. Is there a similar problem there?
Webb: The [standard] “Grip of Death” holding the phone has no effect on Wi-Fi because that antenna is on the top. But if you’re using Skype [for VoIP calls] you might see a problem.
NW: And how can a user fix that?
Webb: Use Bluetooth and put a piece of Styrofoam between the phone and your head. It sounds silly but it will be all the rage soon.
NW: So your advice to iPhone users is…
Webb: Get a bumper and learn the Vulcan iPhone Pinch. And enjoy the phone. I’ve had Apple products since the first Macintosh. This [iPhone 4] is a great product. I love it.
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