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Comment by eli | Hacker News Reader

What's funny is that the little signal bars on the phone don't really mean anything. "Signal Strength" is not a useful measure of anything important if you're not also taking the noise into account. And nobody does that with their phones because the number would constantly be jumping all over the place.

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The little signal bars use an algorithm to represent the constantly moving signal-to-noise ratio. The problem with them is that we know nothing about what's inside the algorithm. From observing the output of field test mode on an older iPhone, I gather this:

* The bars represent a moving average (instantaneous readouts aren't very usable anyway)

* There is a delay in what is reported, even when accounting for the moving average; conceivably to prevent jumpy reports

* The bars use some type of logarithmic scale, which makes sense when you understand digital signal degradation

You sure about that? I admit I don't know about the iPhone, but most every other phone I've seen doesn't take noise into account at all.

I'm curious about the nature of this scale http://images.anandtech.com/reviews/gadgets/apple/iphone4/ba... . Why does it have bar widths of (left to right) 6, 4, 2, 10, 40 dB? How does the logarithmic scale explain that, if it does?

Good point. I'd like to know if most of the people experiencing this problem are actually experiencing lost calls/signal or just seeing fewer bars.

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