Matt Gemmell

TOLL is available now!

An action-thriller novel — book 2 in the KESTREL series.

★★★★★ — Amazon

iPhone 4 Signal Loss Issues

tech 3 min read

I took delivery of two iPhone 4s today (you can see some photos of them on Flickr), and I’m really enjoying the device so far. The screen is impressive, and FaceTime works every bit as well as advertised.

There have been reports of a loss of signal strength when the phone is held in your left hand such as to cause your palm (for example, the major crease of your thumb) to cover the bottom part of the left side of the device - presumably electrically connecting the two separate sections of the exterior case, which are split at that point and two others.

I did a few tests here, and I can indeed reproduce the issue, so I wanted to post my findings. Summary: I completely lose the 3G signal, but Wi-Fi and 2G are unaffected - and I’ve had no dropped calls.

First, my situation here is that, with appropriate antennae activated on the phone:

  • I have 5 bars of wi-fi.
  • I have 5 bars of 3G coverage.
  • I have 5 bars of 2G coverage, and GPRS attachment.

So, pretty much the ideal situation. I’m at my home office in Edinburgh, Scotland (UK), and my iPhone is on the O2 UK network.

In my tests, I never dropped a call. I did, however have signal degradation as I’ll describe. In each case I was calling from my iPhone 4 to my land-line here, answering the land-line, and leaving the call open. I then wandered around the house, checking signal fluctuation both when trying to trigger the issue and when holding the phone flat in my hand, not touching the sides.

I didn’t experience any significant signal loss whilst moving around when I wasn’t attempting to trigger the issue (I did experience a minor fluctuation in 3G, from 5 bars occasionally down to 4 bars, but that’s always been true in this building). The results below show what happened when I did try to trigger the issue.

  3G active     Wi-Fi active     3G Signal loss     2G signal loss     Call dropped  
No No - No No
No Yes - No No
Yes No Yes No No
Yes Yes Yes No No

The results above show that I only experienced 3G signal loss, with no loss of 2G connectivity. In each relevant case my calls were unaffected; I didn’t drop a call at any point. 3G signal loss seems to occur regardless of the state of the Wi-Fi antenna or its connection status.

The loss of 3G signal was admittedly extreme: I lost at least 4 bars (i.e. at best my 3G signal strength was 1 bar of a possible 5, after triggering the issue). In four out of five tests, 3G connectivity would disappear entirely (having previously been at 5 bars).

After placing my hand in the appropriate position to cause the issue, I experienced complete 3G signal loss within an average of less than 10 seconds. In a couple of tests, it would first lose a bar, then another bar, then drop away entirely - but most times it fell away completely within seconds.

If your findings differ from this (I know for example that several people have indeed experienced dropped calls, as shown in the various videos of the issue on the internet), make sure you report them to Apple. It’s been observed that the “Bumper” cases for iPhone 4 (made by Apple) ameliorate the issue since they obviously keep your conductive skin separated from the metal edge of the phone using a layer of plastic.

I’m not overly worried about the issue at the moment, since it doesn’t seem to affect my voice calls and I’m a right-handed caller anyway, and I’m very pleased with the iPhone 4 and iOS 4 in general. We’ll see what happens, and what response Apple may make - I just wanted to share my own experience with you.

For what it’s worth, I didn’t encounter the issue at all until I’d read about it then deliberately tried to reproduce it. I love the phone, and I’d still highly recommend it.