Yes, Your Hand Affects Signals on All Phones

Apple’s claim that iPhone 4 users are causing their own signal strength problems by holding the handset wrong has been met with a considerable measure of derision. Comm0n sense and experience told me that the placement of body parts definitely affects wireless receptions, but I decided to try a little experiment.

Farproc makes a nifty free Android app called Wi-Fi Analyser that turned my Verizon Droid X into an RF signal meter. The results for Wi-Fi won’t be the same as for a 3G signal. Wi-Fi signals are generally a lot stronger to begin with. But the higher frequency–2400 megahertz vs. the 800 and 1900 MHz used for Verizon 3G–are more likely to be attenuated passing through a body, which is basically a big¬† bag of RF-absorbing water.

Sure enough how I held the Droid has a big effect on signal strength. Lying on a desk, I saw -60 dB. Holding it normally, with my right hand more or less around the middle of the phone, that dropped to -70 dB (each drop of 10 dB represents a halving of signal strength.) Holding it with my hand at the bottom, the signal went up to -65 dB. But holding it with my hand at the top drove the signal down to -85 dB and covering both the front and back of the upper part took it all the way down to -95 dB (suggesting strongly that the Droid’s Wi-Fi antenna is in the upper part of the phone.)

The big question about the iPhone is not whether holding it degrades the signal–it surely does–but whether holding the phone in a normal way causes unacceptable signal loss. In the case of the Droid X, the normal hold leaves the Wi-Fi signal well within the limits of acceptability. I’m not sure whether anyone but Apple can do this, but it should not be too hard to instrument an iPhone and get some actual results on the effect of different grips. Neither the anecdotal reports nor the statements of Apple constitute data, and data is what is needed to understand whether there’s a real problem or not.

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One Response to “Yes, Your Hand Affects Signals on All Phones”

  1. Richard Says:

    Steve Gibson of Gibson Research tried to measure this on his iPhone 4, a day or two ago, but could not find an app for the iPhone that showed the signal strength in numbers rather than as less meaningful bars.

    FYI, on a BlackBerry, holding down the ALT key and pressing NMLL turns the graph into a numeric display.

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