Previous 1 2 3 4 5 Next 69 Replies Latest reply: Jul 13, 2010 4:58 PM by kevwright2002 Go to original post
  • 51Cards Level 1 Level 1 (0 points)
    Interesting read. I would point out as well however the person writing the article has clearly not watched the testing video as that is where some of the items he is questioning are stated. (like the 20dB drop) This makes me question the thoroughness of his response. I'm not outright discounting it... but when he missed something that blatant I question how much he researched his reply.
  • mellons Level 1 Level 1 (10 points)
    evil4blue wrote:
    Hmm, not sure who I should believe. A consumer protection group who has been testing equipment unbiasedly for decades, or some random dude with a blog.

    Quoted for truth.
  • Jeff Shaw1 Level 1 Level 1 (30 points)
    So this other Engineer "fails" CR's test. How does he explain the iPhone 4's relative performance vs the other phones tested under (presumably) the same conditions?

    Under this guy's "proper" conditions, would the iPhone 4 likely perform better than the other phones in the CR test?

    Be that as it may, his view is interesting. His point about the software glitch on signal bars is spot on. Without that glitch there might not be such widespread attention on this.
  • John P. Level 4 Level 4 (1,145 points)
    I believe the (real) engineer over a magazine.
  • boxer95 Level 1 Level 1 (0 points)
    As one who works in the RF field, cellular phones in particular, it really is a no-brainer that the iPhone4 antenna design is flawed. The antennas are optimally tuned w/o external conductors, and are covered to avoid changing the attenuations. In making contacting with the antenna, it basically causes the PLL to have to adjust continuously to correct the phase adjustment caused by the change in attenuation. This would cause the call to drop as the constant changes could not be tracked, so to speak. This could have been easily missed as I'm sure that Apple tests on bare PCB within their lab. When the phones would make it out to the wild, it is encased in a dummy shield. There is no solution, really. The antenna will need to be redesigned, plain and simple. Any changes in the antenna will have to clear FCC and that is a lengthy process, so the only thing Apple can do is to mask the problem by adjusting the signal algorithm. Buying a phone and having to buy a bumper/case as a necessity is simply not accepted. That's just like buying a car without tires. The car can go on bare rotors, but having tires are necessities to ensure a smooth ride.

    IMO, Apple failed to deliver this time.

    P.S. I'm an electrical engineer, and the CR's test methodology is fine. In fact, I thought it went slightly overboard to try and isolate the external interference, but that's just trying to remove any doubt by testing inside an RF chamber. The end result should be the same, with or without the RF chamber.

    Message was edited by: boxer95
  • Stevenam81 Level 1 Level 1 (25 points)
    Exactly! Great first post. I wish these Apple fanboys would get this through their head. Hopefully Apple will have to admit fault soon and we can sit back and say "I told you so" to all of those in denial.
  • Mike Masquith Level 1 Level 1 (5 points)
    Quick question...
    Why the anechoic chamber? I've seen this specified before with RF tests, and I don't understand.
    Isn't an anechoic chamber meant to absorb sound? What affect does it have on radio waves?
    Or is there a 'radio' version of an anechoic chamber?
  • Wallace Mcmillanjr Level 1 Level 1 (70 points)
    Actually, CR did lose a case that was brought by BOSE Corp. It had to do with a review of the BOSE 901 speakers.
  • John P. Level 4 Level 4 (1,145 points)
    I doubt you are a real engineer until I see qualifications. Sorry, not personal. CR said they had "engineers" as well but anyone with a HS diploma can call themselves an engineer.
  • boxer95 Level 1 Level 1 (0 points)
    Mike, the chamber used to conduct the signal strength test on the iPhone4 is inside an RF chamber, made of copper to isolate the device under test from external noise. The chamber is not an RF anechoic chamber, in this instance.
  • wowKrash Level 1 Level 1 (0 points)
    I'm an electrical engineer. While the guy may have some points, the perfection of the test is not relevant. What is relevant is that it's quite easy to see the signal to noise ratio using an iPhone, and to watch the signal drop precipitously when you "cup" the phone in your left hand, bridging the antennas on both sides. I've seen it myself. When a friend of mine was showing me his new phone, he easily demonstrated dropping from full bars to no bars. We even had him call my phone and then do it, and the result was that the call dropped.

    I don't need any more evidence than that. Hundreds of people are seeing this. Apple knows that the solution is the rubber "bumper". Ultimately they will be forced to give them away to solve the problem. It's just the reality of the situation.
  • boxer95 Level 1 Level 1 (0 points)
    John, I'm a BSEE specialized in communications from Cal Poly Pomona. Whether you believe me or not, that's up to you.
  • 51Cards Level 1 Level 1 (0 points)
    John P. wrote:
    I doubt you are a real engineer until I see qualifications. Sorry, not personal. CR said they had "engineers" as well but anyone with a HS diploma can call themselves an engineer.

    How about I just question if the guys who designed the iPhone in the first place were even engineers? I haven't seen their credentials personally so perhaps they were just a bunch of hacks. CR has been testing mobile devices longer than Apple has been making them.

    The Apple forum needs a 'roll eyes' icon badly.

    PS. Wait! Perhaps this is why Apple posted three job postings for antenna engineers the day before the iPhone 4 launched (yes, I couldn't resist)
  • Abcat Level 1 Level 1 (0 points)
    Far to techy for me. All I know is I have a £500 phone that's not up to scratch, if it cost £300 then fine I would live with it but it's just far too expensive to have so many problems R.I.P
  • MrCourtney Level 1 Level 1 (0 points)
    I doubt you are a real engineer until I see qualifications

    John -

    What he says makes sense from an engineering point-of-view. Onde can't make that up and sound credible.
    He's an engineer.