Apple confesses: iPhone Signal Strength Indicator “totally wrong”

Apple Computer (NYSE: AAPL), stunned the world today by announcing a critical error in the design of their iPhones, which has been present since the devices were first manufactured and sold in 2007.

It seems that the “bars” indicator – which has been used as a signal strength indicator, albeit an inaccurate and faulty one – is even more faulty than previously thought! In fact, it’s AFU – All Fouled Up. (That’s nice parlance.)

For those of you who do not know how to read radio signal strength indicators (and that’s very likely most folks), they’re expressed in negative numbers. The higher the negative number, e.g., -108, the weaker the signal. Conversely, the opposite is true: The lower the negative number, e.g., -16, the stronger the signal.

My iPhone 3GS is jailbroken, and one feature I have employed on it is a numerical signal strength indicator for the Cellular and WiFi signals. Here are two screenshots to illustrate.

UPPER LEFT CORNER: Cellular signal strength indicator using "Bars" - Note also, the WiFi signal (on the RIGHT of the AT&T) is much stronger than the cellular signal.

UPPER LEFT CORNER: Cellular strength indicator using the accepted numerical standard - Note also, the WiFi signal (on the RIGHT of the AT&T) is much stronger than the cellular signal.

Oh!

And if you’re looking for a job…

Apple Computer is looking for Antenna Engineers, too!

Read on to see their mea culpa and want ad.

http://jobs.apple.com/index.ajs?BID=1&method=mExternal.showJob&RID=55849&CurrentPage=1

Job description

Requisition Number	5289164
Job title	Antenna Engineer – iPad/iPhone
Location	Santa Clara Valley
Country
City
State/Province
Job type	Full Time
Job description	Responsibilities: Define and implement antenna system architecture to optimize the radiation performance for wireless portable devices. The candidate should be able to design antennas suitable for wireless handheld devices with excellent radiation performance, including TRP, TIS, SAR, and EMC. Work closely with other RF and antenna design engineers, mechanical and industrial designers, and EMC engineers to integrate the antenna design in our products. The candidate will be expected to performance radiation performance measurements, create test plans, execute them, publish test reports, provide feedback to the other design engineers, and lead some of the manufacturing of antenna. Skills and Experience: * 10+ years of experience in RF with at least 5 years in antenna design and test for wireless consumer products. * MSEE required, PhD is preferred. * Must have working experience of antenna design and tests, anechoic chambers, and RF test equipment. Hands-on is a must. * Must have strong problem solving skills and strong working knowledge of radiation performance. Antenna and wave propagation theoretical background is essential. * Experience with different wireless communication systems such as GSM/GPRS/EDGE, 802.11, Bluetooth, etc., including the corresponding system level specifications (e.g. ETSI 51.010, 51.05…) is essential. * Experience with regulatory requirements and process for wireless consumer devices, including FCC, PTCRB, CTIA, ETSI, TIA/EIA, etc. * Excellent communication skills required, both written & verbal. * Detail oriented – taking data, using Excel, and making meaningful tables/graphs/averages. Preferred Experience: * Experience with simulation tools such as XFDTD, HFSS is a plus.

Letter from Apple Regarding iPhone 4.

http://www.apple.com/pr/library/2010/07/02appleletter.html

July 2, 2010

Letter from Apple Regarding iPhone 4

Dear iPhone 4 Users,

The iPhone 4 has been the most successful product launch in Apple’s history. It has been judged by reviewers around the world to be the best smartphone ever, and users have told us that they love it. So we were surprised when we read reports of reception problems, and we immediately began investigating them. Here is what we have learned.

To start with, gripping almost any mobile phone in certain ways will reduce its reception by 1 or more bars. This is true of iPhone 4, iPhone 3GS, as well as many Droid, Nokia and RIM phones. But some users have reported that iPhone 4 can drop 4 or 5 bars when tightly held in a way which covers the black strip in the lower left corner of the metal band. This is a far bigger drop than normal, and as a result some have accused the iPhone 4 of having a faulty antenna design.

At the same time, we continue to read articles and receive hundreds of emails from users saying that iPhone 4 reception is better than the iPhone 3GS. They are delighted. This matches our own experience and testing. What can explain all of this?

We have discovered the cause of this dramatic drop in bars, and it is both simple and surprising.

Upon investigation, we were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong. Our formula, in many instances, mistakenly displays 2 more bars than it should for a given signal strength. For example, we sometimes display 4 bars when we should be displaying as few as 2 bars. Users observing a drop of several bars when they grip their iPhone in a certain way are most likely in an area with very weak signal strength, but they don’t know it because we are erroneously displaying 4 or 5 bars. Their big drop in bars is because their high bars were never real in the first place.

To fix this, we are adopting AT&T’s recently recommended formula for calculating how many bars to display for a given signal strength. The real signal strength remains the same, but the iPhone’s bars will report it far more accurately, providing users a much better indication of the reception they will get in a given area. We are also making bars 1, 2 and 3 a bit taller so they will be easier to see.

We will issue a free software update within a few weeks that incorporates the corrected formula. Since this mistake has been present since the original iPhone, this software update will also be available for the iPhone 3GS and iPhone 3G.

We have gone back to our labs and retested everything, and the results are the same— the iPhone 4’s wireless performance is the best we have ever shipped. For the vast majority of users who have not been troubled by this issue, this software update will only make your bars more accurate. For those who have had concerns, we apologize for any anxiety we may have caused.

As a reminder, if you are not fully satisfied, you can return your undamaged iPhone to any Apple Retail Store or the online Apple Store within 30 days of purchase for a full refund.

We hope you love the iPhone 4 as much as we do.

Thank you for your patience and support.

Apple

Press Contacts:
Natalie Harrison
Apple
harri@apple.com
(408) 862-0565

Steve Dowling
Apple
dowling@apple.com
(408) 974-1896