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Monday, February 20, 2012

How far does it go, mate?

Geoff Varrall of RTT writes:

About 15,000 years ago some indigenous Northern Australians decided that they needed a more efficient way of talking to each other than just shouting a lot.

And blowing into a long cylindrical tube proved to be just what was needed and seriously useful fun – the dawn of the didgeridoo.

Trumpets and bagpipes were invented at about the same time. The ancient Greeks used the trumpet in battlefield communication to devastating effect.

The way you can tell that your didgeridoo is better than everyone else’s didgeridoo is to blow into it and see how far the sound goes.

So naturally when an Australian goes in to buy a mobile phone from a Telstra shop the first question is “how far does it go mate?”

And the answer is on the box.

Telstra tests phones in the laboratory and, if they perform well, they go off for a drive in the outback for some comparative testing.

If the phone works beyond the edge of the operator’s coverage map it gets a blue tick – it really is that simple – and we might well ask why other operators don’t do the same.

We have all got used to our phones working more or less anywhere at least for voice and text but getting decent data rates anywhere other than close in to a cell site is much more problematic.

Very few of us would even think about checking whether the phone we were buying had good radio performance – and actually we have no way of finding out until we start using the device and then we blame the network not the phone.

This would not matter if all phones worked equally well but they don’t. They all meet a basic conformance standard but the conformance tests don’t recreate real life conditions.

Most new phones including LTE phones are what are called ‘uplink limited’.

This means that the data rates and data reach (the distance from a base station where you can still get a data link) are constrained by the ability of the device to get useful RF energy out of the antenna.

If your phone gets hot it’s a pretty good indication that it’s working harder than it should be. That’s probably because it’s been crammed into an outer casing that looks great but is too small to allow the antenna to work efficiently.

In engineering terms the amount of efficiency or rather inefficiency can be described by measuring how much energy gets reflected back into the device rather than out of the device.

That’s not the sort of test you want to do in a shop but that’s not a reason to ask the right question, not ‘how fast does it go’ but ‘how far does it go’.

Britain is not Australia and we don’t have those big wide-open spaces but data reach, the distance from a base station where we can still get a data connection, is every bit as important as data rate.

The moral of the story is don’t buy a dud didgeridoo.

Geoff Varrall has just written a new book Making Telecoms Work - from technical innovation to commercial success published by John Wiley.

Given that we have 15000 years of telecoms history to draw upon, it’s amazing how many stupid decisions we still manage to make.

The book uses prior case study examples of technical and commercial success and failure to qualify present policy making in the industry.

The book is available from Amazon and can be ordered via the RTT book shop.

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Author: The Fonecast
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