I looked into how the bumper case affected the signal loss problem earlier. It helped lessen the signal loss, but still lost a couple bars. I’ve been thinking about this issue all day and decided to dig a bit deeper to see what I could find.
UPDATE For those of you that don’t have this issue, my best guess…I wrote earlier today in my bumper case post:
I then tested in another room with less electronics. In this room I started with a strong signal of 5 bars. This time around, with or without the bumper, the signal held pretty much at 5 bars. This may explain why some people don’t seem to notice this issue. If you have really great AT&T service where you live, the in hand signal drop may not be as noticeable.
Watch the video of this phenomena.
I definitely have the signal loss issue and more specifically, the left hand covering the bottom left corner problem. Engadget points out that this is where the Bluetooth / WI-FI / GPS antenna meets the UMTS / GSM antenna. This is true, but there is also another meeting point at the top of the phone as seen in the antenna diagram. Holding the top of the phone doesn’t produce the same effect as the bottom left.
I decided to take it a step further to see if the 2 antennas were “electrically separate”. I pulled out my handy multimeter and got to measuring. I started as an electrical engineer in college, but later switched to computer engineering, so if anything I’m saying sounds off, let me know @justin_horn.
UPDATE @armadsen tweeted the following:
DC resistance measurements are not valid for antennas, it’s RF impedance that matters. Much more difficult to measure.
Guess that pokes a whole in this theory?
As you can see from the pictures above, there is basically zero resistance between the two antennas. This means we aren’t bridging “the gap” and shorting the two antennas because they are already connected. Ruling out this bridging effect explains why the top gap doesn’t suffer the same issue.
UPDATE Continuing to test this, it’s hard to argue with the bridge theory. I just place one finger (you know which one Apple) right on the separator and the signal starts to drop. What I don’t get is how this doesn’t effect the upper gap, theoretically it should be the same right? Check out Marco Arment’s solution, spoiler alert: masking tape.
According to people I’ve spoken with, it could be that moisture from your fingers is causing the iPhone 4 to believe that the antenna is receiving interference and losing its wireless signal
So the best I could come up with to test this is the good old rubber glove test!
Rubber glove, same result. This was only testing the moisture idea, but I’m thinking it has to do more with the fact that the human body is a conductor. Somehow this conductive nature of the human skin is sapping the signal or just disrupting it somehow.
I remember back in olden days, touching rabbit ears for an analog TV broadcast actually improved the signal, but with the iPhone 4 it’s worse. I’m not really sure why, but I have a few guesses:
1) It doesn’t work the same for digital signals
2) Cell phone frequency range reacts differently to human conductivity than TV (analog or digital)
3) iPhone is a transmitter and a receiver, not just a receiver like a TV
The rubber glove I used was thin enough that it didn’t stop the flow of electricity, so to test this I needed something thicker. I decided it was time to bring out the big guns…The Ove Glove.
This test produced the best results with zero signal loss, even trumping the results I got with the bumper earlier! Another plus, the Ove Glove is half the price of the bumper [Buy your ove glove on Amazon].
Even though I’m not sure why human conductivity would weaken the signal, after this last test I believe it’s cause. At this point I really don’t think there is anything Apple can do to fix this, so go buy your Ove Gloves!
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