Wireless Waffle - A whole spectrum of radio related rubbish
Is 5 better than 2.4 (GHz)?signal strength
Thursday 9 August, 2012, 15:13 - Radio Randomness, Spectrum Management
Posted by Administrator
wi five logoAlthough the standard for WiFi at 5 GHz has been around for a long time, most manufacturers have focused upon producing equipment for the 2.4 GHz band. The reason for this is a simple one - it's cheaper! The higher you go in frequency, the more difficult, and therefore expensive, it becomes to transmit and receive radio signals. As a result, home routers, laptops, smart phones and other devices have almost exclusively been equipped to use the 2.4 GHz band for their WiFi connection.

Previous Wireless Waffle articles have discussed how to select the best WiFi channels in the 2.4 GHz band, and other techniques, to maximise coverage and signal quality, however we have not looked at the 5 GHz band. Recently, there seem to be a slew of articles which are claiming that using 5 GHz will produce better range and more reliable connections compared to 2.4 GHz. The logic of these articles seems to go '5 is a bigger number than 2.4 - in fact it is more than double - so it must be at least twice as good'. This, sad to say, is not the case. Here are the real facts:
  • Signals at 5 GHz only travel HALF as far as those on 2.4 GHz as higher frequencies have poorer coverage than lower ones.
  • Signals at 5 GHz will struggle almost TWICE AS HARD to get through walls than signals at 2.4 GHz due to their poorer propagation characteristics.
  • 5 GHz WiFi equipment is subject to exactly the same POWER RESTRICTIONS as that for 2.4 GHz, so there is no inherent advantage in terms of the technology itself.
  • The use of some of the 5 GHz channels is subject to the requirement to STOP TRANSMITTING if a nearby radar is detected. No such restriction applies at 2.4 GHz.
  • 5 GHz equipment will be (slightly) more POWER HUNGRY than its 2.4 GHz counterparts, increasing battery drain especially in mobile devices.
  • 5 GHz receivers are likely to be LESS SENSITIVE than 2.4 GHz receivers because of the increased difficulty of making low noise devices at higher frequencies.
  • The 5 GHz band consists of up to 25 (territory dependent) independent channels which can be used without interfering with each other meaning there is much GREATER CAPACITY for more networks, whereas the 2.4 GHz band has 13 channels of which only 3 can be used independently.
  • The 2.4 GHz band is also used for Bluetooth, microwave ovens, wireless cameras and many other applications meaning it can be subject to a lot of background interference. The 5 GHz band is MUCH CLEANER, though the band is not exclusive to WiFi systems.
  • There are still fewer 5 GHz devices around than 2.4 GHz once and hence it is likely to be LESS SUSCEPTIBLE TO SNOOPING.
As coverage is determined both by signal strength and by the amount of interference, it is therefore possible that people in particularly densely populated areas where there are lots of 2.4 GHz users around might find that the 5 GHz band provides a more reliable connection and may even provide greater coverage. In most cases, however, the 2.4 GHz band has many advantages and the claims being made that 5 GHz is somehow 'twice as good' are just plain wrong.

For a home network, in a small house or apartment, using 5 GHz may offer some advantages given the lower interference it will suffer from other devices, but in large family homes a 5 GHz WiFi router is unlikely to be able to outperform the coverage and range that a 2.4 GHz router achieves.

five is betterWhere the 5 GHz band may come into its own is when the not-quite-yet-finalised IEEE 802.11ac standard is adopted. This works in the 5 GHz bands and uses the greater capacity of the band to deliver connection speeds of up to 1 Gbps. For streaming media around, this has clear advantages. As a wireless distribution for a home internet connection, however, there is unlikely to be any improvement noticeable using 802.11ac than with the existing 802.11n standard which can already offer connections of over 100 Mbps - much faster than most home internet connections!
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