Over the past few months I have been getting an increasing number of requests for help to setup WiFi networks. I am not just talking about the initial setup, but many ongoing reliability problems. At first I was blaming vendors as most of the problems seem to be associated with one vendor, Belkin. However as time went by, I realised the issue was not just Belkin but applied to a lot of other vendors too. The common factor seemed to be the use of the default channel number and changing the channel fixed the issue.
Then the penny dropped when I re-organised my AV kit at home. Wireless Video senders, wireless security cameras and some baby monitors also use the 2.4 Ghz band.
So I thought I would do some investigation along those lines. I was shocked at what I found.
Firstly the 14 WiFi Channels (not all are available in every country see http://en.wikipedia.org/wiki/List_of_WLAN_channels) have massive overlap, so in a busy area lot of interference will result, reducing the throughput in many circumstances.
Secondly the wireless Video channel could not have a worse frequency allocation, and have the potential to wipe out WiFi signals. Especially as unlike WiFi , which sends in bursts and waits for a reply, an AV sender sends a continuous carrier.
I have created the following diagram to demonstrate the frequency clashes
Click on the thumbnail for the full diagram
My son got a copy of the Nintendo DS transformers game for XMAS, and decided to try out the WiFi features over the weekend.
I had heard the some WiFi routers and access point do not work well as the DS wireless if not fully WiFi compliant. They aren’t kidding, more like not RFC compliant in many areas.
NO support for NON wep security
A TCP/IP stack that does not confirm it has taken the DHCP address it was offered and then does not respond to ping, instead it just uses it and says nothing, so the next new device connects to the network, gets the same address, and the DS gets kicked off,
Well after waiting 3 weeks by FON router (with optional 7dB antenna) finally arrived on Friday
Much to my surprise, it did the business straight out of the box
Plugged it in to my network and away it went (using the serial no for the private network WPA key)
Logged into the FON web site via the FON_AP public WiFi configure the location and that is it done, the FON locate WiFi maps now shows my house as a FON node.
Jobs a good’n
In a total geeky moment of boredom i have carried out a WiFi survey
Having used my tructy PDA and a copy of WiFiFoFum here are some of the results
Total discover access points 1005
Access point with NO Wep 227
Access points with BTHomeHub SSID 128
Access points with linksys SSID 39
Access points with belkin 93
Access points with livebox 27
Access points with sky 121
Access points with netgear 39
Access points with 2wire 22
Access points with BTopenzone 2
Access points with with hiden SSID 29
number of unique SSID 714
channel number
1 313
2 11
3 12
4 10
5 9
6 209
7 18
8 7
9 26
10 16
11 351
12 6
13 17
The BT FON WiFi community was launched on the 4th October, I immediately signed up. The community sharing of a small amount of my internet bandwidth, for a massive increase in locations I can get some sort of internet connection seems like a great deal. My best guess is that it will take 9-12 months for this to reach critical mass, such that a free, legal, wifi connection will be available on almost every corner in every estate.
10 days after agreeing to opt-in to BT FON, the firmware on my BT Homehub was upgraded over the wire and started advertising itself as a BTOpenzone hot spot. An examination of the hub configuration laid my main fear to rest, my original configuration has not been touched, and the hub continues to operate on the 10.x.x.x address I use, instead of the more traditional 192.168.x.x. Unfortunately I am no longer able to configure the advanced IP addresses via the web interface so let’s hope I don’t want to change anything.
My Homehub is now running V6.2.6.B, although I have seen 6.2.6.C mentioned on a few forums, I wonder how different that is…….
Well what can i say, just watched panorama and there scare mongering attack on WiFi etc
Dont get me wrong, there could always be a small risk, but the manor in which is is presented was nothing more than scare mongering…. (does make me wonder about the presetation of the scientology investigation)
Using generic RF level meters to look for RF radiation is complete waste of space, one guy had the right approach using a spectrum analyser, and comparing the Levels at particular frequencies, but did nothing to explain the graphs
Mobile phone and Wifi frequencies at over an octave apart, and will have very different effects and interferance patterns
Picture this, typically only one frequancies will break any particular glass, a sound wave lass than an octave either way, will not break the glass. Therefore any PROVEN findings from specific mobile phone invetsigation, MAY NOT apply to other mobile phone network technologies, let alone WiFi !!!!
After much googleing and faffing, i have managed to
- get my SIP softphone (VOIP) to connect to my asterisk box at home with out the use of a VPN
- Get RPC over HTTP email to work
- setup WEBDAV over SSL access to my file server
So I no longer need the VPN to do normal networky stuff to home, the only reason i need the VPN now is to trick Sky Anytime into thinking I am in the UK, and that is only the gui client, the peer to peer service does not give a stuff, so once i have requested the video, i can drop the VPN !
I am Glad i am NOT paying to the t-mobile WiFi usage !!
