Skip to navigation

PCPro-Computing in the Real World Printed from

Register to receive our regular email newsletter at

The newsletter contains links to our latest PC news, product reviews, features and how-to guides, plus special offers and competitions.

// Home / Blogs

Posted on August 19th, 2011 by Jonathan Bray

What’s really killing your Wi-Fi? Here’s a graphic illustration

We’ve written many times about how crowded the 2.4GHz frequency band is becoming these days, and how that can affect the reliability and speed of your wireless network.

There are so many devices and routers now using the unlicensed space between 2,400MHz and 2,475MHz that finding a quiet, undisturbed channel for your network to reside on is nigh on impossible. That’s why we recommend anyone upgrading their wireless router chooses a dual-band model — one that gives you the option of connecting in the less congested 5GHz frequency band.

This can be a difficult concept to grasp without visual aids, so let me show you exactly what we mean when we talk about RF congestion.

Chanalyzer 4 - local 2.4GHz RF spectrum analysis

Using our recently-acquired Wi-Spy spectrum analyser (kindly supplied by Metageek for use in a forthcoming wireless router Labs), combined with the firm’s Chanalyzer 4 radio frequency (RF) analysis software, we recorded the above graph.

It shows all the RF activity in the vicinity of the PC Pro office, and can detect not only nearby wireless networks – of which there are an alarming number — but also other devices using the 2.4GHz band.

Look closely and you’ll see that, on channel 8, there’s a non-Wi-Fi source of interference, represented as three bright stripes in the bottom “waterfall” window: I’ve not tracked down the culprit yet. To the right, the broad red/green stripe flanked by two narrower vertical green  lines shows you the devastation a cheap wireless video sender can wreak.

While this might seem a rather extreme example, I’m sure that many living in densely populated urban centres will be surrounded by a similar level of congestion and interference. Just imagine how many baby monitors, cordless phones and wireless routers there are in a modern, central London block of flats, and you’ll get the idea.

It’s frequency band bedlam out there, and the effect is slower, more unreliable wireless networks. Now take a look at the 5GHz band at the same location:

Chanalyzer 4 - local 5GHz RF spectrum analysis

The difference is quite staggering — an oasis of calm by comparison, with only PC Pro’s own dual-band wireless router interrupting the tranquil RF landscape.

If that doesn’t get you hankering after a dual-band router, then nothing will.

Tags: , , , , ,

Posted in: Hardware, How To, Random


Follow any responses to this entry through the RSS 2.0 feed.

You can skip to the end and leave a response. Pinging is currently not allowed.

5 Responses to “ What’s really killing your Wi-Fi? Here’s a graphic illustration ”

  1. Paul Says:
    August 19th, 2011 at 5:05 pm

    This issue with using 5Ghz is that most laptops, mobile phones etc only have 2.4GHz radios in them as standard and until they are upgraded the congestion will continue,

  2. DeanC Says:
    August 19th, 2011 at 6:46 pm

    interesting stuff; cant wait till the Wireless Router labs its been a while since the last one!!!

  3. Jamie Says:
    August 19th, 2011 at 7:11 pm

    your link doesnt work, but inSSIDer is a great little tool. :)
    Only problem i found is old wifi cards cant always find g bands higher than 11 where it is usually less crowded.

  4. Paul B Says:
    August 20th, 2011 at 1:48 am

    The only problem I have is that my media streamer downstairs doesn’t have 5Ghz support – I’m just hoping a new 5Ghz compatible adaptor is released for it.

    Another good thing about running your wireless on the 5GHz band (which I think wasn’t mentioned) is that the wireless signal doesn’t travel as far on this band, so there’s less chance of polluting your neighbour’s reception.

  5. Adrian Says:
    August 26th, 2011 at 1:04 pm

    Move to the countryside.


Leave a Reply

Spam Protection by WP-SpamFree

* required fields

* Will not be published






Your email:

Your password:

remember me


Hitwise Top 10 Website 2010