How Wi-Fi works
Second, since the channels are further apart than in the 2.4GHz band (with 20MHz between each, compared with 4MHz or 5MHz) there’s much less opportunity for adjacent channel overlap. Even in the unlikely event that many 5GHz routers and devices are in close proximity to each other, maintaining a steady signal should be much easier.
Finally, and potentially the biggest bonus of all, there are relatively few non-networking devices currently using the 5GHz space.
Where users of 2.4GHz must contend with all manner of domestic interlopers, from microwaves to cordless phones (see What can get in Wi-Fi’s way, p92), 5GHz networks are comparatively clutter-free.
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It isn’t all rosy in the 5GHz garden, though. Since the signal is of a higher frequency than 2.4GHz, it deals less well with walls, windows and floors, and this hits its ability to transmit and receive speedily at long range.
In PC Pro tests, we’ve routinely seen routers perform well over 2.4GHz, flawlessly transferring files wirelessly at a distance of about 40m, with two walls in the way.
When tested in the same location over 5GHz, most suffer a significant drop in transfer speed and weaker signal reception. Some fail to maintain a solid connection entirely. That means the more objects blocking your signal path, the worse the reception in the 5GHz band gets. It isn’t only building materials that get in the way – everything from humans to heavy rain can attenuate a wireless signal.
Choosing a 5GHz router
Restricted range isn’t the only problem afflicting 5GHz routers. Many devices, such as smartphones, internet radios and games consoles, don’t send or receive signals in that band.
It’s really only laptops and PCs with premium wireless cards that will take advantage of the 5GHz band.
That’s why high-end routers typically offer the choice of 2.4GHz and 5GHz bands, but you should take care when choosing a dual-band router.
Some routers can transmit on both bands simultaneously, while others require you to manually flick between the two. Needless to say, the former is the better choice.
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