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Apple Hires Antenna Engineers. Really.
kangsterizer writes "Sometimes, news items are just about a good laugh. You may or may not like Apple, but the way it has been handling its antenna issue has been like a small tech soap opera — Steve Jobs, the CEO, saying 'not to hold the phone that way,' rumors of software issues, and the latest but most crunchy part, since the antenna issue has been widely discovered, on 23 June, several 'antenna engineer' positions opened up at Apple. Seems someone got fired:
Antenna engineer job position 1,
Antenna engineer job position 2,
Antenna engineer job position 3."
I just figure they did all their testing in California, where AT&T dropping calls is as common as $4 coffees.
From a memo to AppleCare reps:
Exact procedures AppleCare reps must follow when dealing with any reception complaints regarding the iPhone 4.:
1. Keep all of the positioning statements in the BN handy – your tone when delivering this information is important.
a. The iPhone 4’s wireless performance is the best we have ever shipped. Our testing shows that iPhone 4’s overall antenna performance is better than iPhone 3GS.
b. Gripping almost any mobile phone in certain places will reduce its reception. This is true of the iPhone 4, the iPhone 3GS, and many other phones we have tested. It is a fact of life in the wireless world.
c. If you are experiencing this on your iPhone 3GS, avoid covering the bottom-right side with your hand.
d. If you are experiencing this on your iPhone 4, avoid covering the black strip in the lower-left corner of the metal band.
e. The use of a case or Bumper that is made out of rubber or plastic may improve wireless performance by keeping your hand from directly covering these areas.
2. Do not perform warranty service. Use the positioning above for any customer questions or concerns.
3. Don’t forget YOU STILL NEED to probe and troubleshoot. If a customer calls about their reception while the phone is sitting on a table (not being held) it is not the metal band.
4. ONLY escalate if the issue exists when the phone is not held AND you cannot resolve it.
5. We ARE NOT appeasing customers with free bumpers – DON’T promise a free bumper to customers.
This space for rent.
A new meme was born and they saw it was good.
Did you even check the AnandTech article? The antenna still works with the user holding the device. Like many other devices, attenuation occurs when the antenna is covered, especially when in contact with the human body. This attenuation is mitigated by the fact that signal quality is improved even at the lowest signal strengths. However, it is significant enough to cause disruption if the user is in an area with a weak signal already.
As the AnandTech tests show, part of the problem is in the way that the signal strength is reported by the "bars" meter, a weak signal around 40% of the maximum supported still shows up as "5 bars". When attenuated by touching the antenna in the right place this gives the illusion of a drop from full strength (5 bars) to none, which seems more dramatic than it really is.
The attenuation is marked, there is no argument about that. However, even AnandTech suggests that coating the antenna with an insulative should help mitigate it even more. In other words, it seems to be a sound design, based on solid engineering, with perhaps some implementation flaws due to the rush to market.
-dZ.
Carol vs. Ghost
(or I suppose they could just watch for a sudden drop in signal strength and try adjusting up, see if it helps, then try adjusting down if it made things worse).
auto antenna tuners exist. There is no need to guess by trial and error. Simply measuring the antenna current and comparing the phase of the current will tell you the tuning direction needed. When the current is in phase with the voltage, the antenna load is resistive (in tune). When the current leads the voltage, the antenna is capacitive and needs less capacitance (tuned higher in frequency) and vise versa.
Unfortunately, auto tuners for microwave frequencies are difficult to design due to the very short mechanical dimensions of the parts. Voltage tuned capacitors (diodes) are common in VHF and UHF, but not as common in microwave applications for tuning antennas due to their limited tuning range. A hand contacting a microwave antenna can tune it much further than the corrective auto tunning can correct it in most applications. Even if tuned to resonance, the new tuning to correct for the hand contact will still not have the impedance change corrected. Energy absorbed by microwave heating of the hand is energy not received or transmitted by the phone. Tuning is only part of the problem.
Attenuation is a real problem at these frequencies. To demonstrate this, simply tape an orange near the LNB in a satellite antenna in the path of the feedhorn. Without de-tuning the feedhorn cavity, the huge loss in signal strength by absorption can be seen as a total loss of reception. Try placing your hand over the feedhorn while setting up your satellite TV dish. Active retuning of the feedhorn to resonance won't fix the total loss of the signal.
HF for Ham radio and marine shortwave (2-30 MHZ) need larger components to tune mechanically larger antennas so those applications use mechanical relays to switch capacitors and inductors or motor driven capacitors and/or inductors.
The truth shall set you free!