IPhone 4 antenna problem was reveled. The antenna of all evils. “We found that the formula we use to calculate the number of bars to display based on the signal strength is totally false,” Apple said Friday. For the company, so there is no structural problem in the iPhone 4. Simply, a formula that shows too many wrong bars when the signal is already low at IPhone 4. Consequence: a grip, “which affects the reception of all phones,” according to Apple, sometimes seems to lose four or five bars, while in reality the loss is not as important. A bit like a thermometer showed that it is 0 °, 18 ° outside, and that was to keep the increase to 20 °. But if there is a problem thermometer, the patient is not as healthy as Apple said, according to testing experts of IPhone 4.

Keep any phone a certain way will reduce its receipt of a bar or more,” says Apple trying to explain the IPhone 4 problem. It’s true, says Richard Gaywood, who holds a doctorate in array antennas. The manufacturers have abandoned the external antenna but not IPhone 4. Hold the phone, especially in the area covering the internal antenna, thus affects the reception and so is the iPhone 4. According to Anandtech test site, that of the iPhone 3G loses up (by being held firmly) 14.3 against 17.7 dB One at Nexus and 24.6 to iPhone 4. he famous “How did you bar” is not scientific. There is, in fact, no international system. Each manufacturer is free to do his own cooking. Clearly, four bars in one may be better than five in the other. What matters is the strength of the signal attenuation in decibels (milliwatts and its variants, in dBm). Warning, it is not linear but logarithmic. This means that a “small” difference of 10 dBm results in a factor of 10 signal attenuation (and 20 dBm, or 2 nice, a factor 10 ² = 100).

Apple said they used the same formula since the first generation iPhone (some were speculating on a change with the iPhone 4 to “hide” artificially low quality network operator AT & T).

We see that the area corresponding to five bars is very broad: from -50 dBm (the best signal) to -91 dBm. This means that a user located near an antenna relay, the high end, five bars to rest, even with a grip and a loss of 20 dBm. However, for those in the lower range (or worse, already four bars), lose 20 dBm took him directly to a bar (a “drop in audio quality” in the case of the iPhone 4, according Anandtech) or even lose the signal. Translation: it cuts.

All phones are so sensitive to touch. Some more than others. Except in the case of the iPhone 4, things improved greatly when it is kept covered with a sheath-bumper protection. It loses more than 7.2 dBm. It is even better than the Nexus One (7.7), but less so than 3G (3.2). Clearly, with or without case, it should not be any major difference. According to Richard Gaywood (and other experts), this is a sign of a “design flaw” of the iPhone 4 in which the external metal frame plays the role of additional external antenna. It consists of two parts (top photo article). Touch the black terminal, bottom left, seems to create interference … Disappear with the isolation of a plastic (or tape and nail polish, a solution adopted by some hobbyists).

Yes, according to Anandtech. “The performance is much better with the iPhone 4 in case of weak signal. I have spent many calls in areas where it was not possible with 3G, “relates the site. In sum, the new design improves the reception of iPhone 4. A condition of accepting a case using several tens of dollars not really aesthetic. The software update from Apple will not change the problem of iPhone 4: the famous “bar” will be just a little more representative of the state of the network. We are back to square one: do not cover the left corner of his iPhone 4, protected by a shell, or return it to the Apple store within 30 days of purchase for a full refund. “I expect my case free,” laughs Richard Gaywood. A gesture at this juncture by Apple.