2.4 Ghz

 

 

 

Another form of scanning we enjoy is Wireless Network Finding on 2.4Ghz.
It comes in handy when out and about with the laptop when we're in need of
accessing the internet courtesy of open networks, especially on holidays :)
A good tool for sniffing these hotspots is a Canary Wireless Hotspot Finder
which I aquired off  E-Bay  for about £43 and works similar to a Sniffer. 
IT tells you whats in range, the SSID Broadcast name, if its open or secure
as well as channel and signal strength. This tool is very handy & i,d
recomend this for anyone sniffing out hotspots. The distance for reception is
rougthly 300ft...

The Canary HS10 Wifi Hotspot Finder
My 2.4 Ghz Cantenna (Sky mini-dish mounted)

 

 
A antenna project I,ve been toying about with is my Cantenna which i built
using various diagrams i have found on the net, i am very impressed with the
performance of this 'cheap' and 'easy' to build wireless aerial so i have added
photo's with instructions how to build this home made 2.4Ghz aerial with some
comparisons of reception using the cantenna compared to the internal aerial
built into my laptop..
What I Used:-    

 

 I found a old tin-sign sheet about A4 size
I Shaped this into a Can shape using the
dimensions in the diagram below. Altho i used a
sheet its easier to use a ready made can.
I searched thru Tesco's for lots of cans
that came close to the needed diameter.
Nearest i found was a Whisky bottle Can
but it was too tempting to buy it and get pissed!
I did howether make a cantenna using a slimfast
can which was slightly wider and not as long but
also gave good results....
I used a sheet of tin-metal (old tin-sign)
N-type Chassis + SMA Pigtail
  
For the probe i used a brass spacer you find on motherboards
with a threaded screw in top for fine tuning.

After aquiring a Sky Mini-Dish I strapped the finished
Cantenna to the LNB arm replacing the LNB making sure
the open end of the cantenna was facing the center of
the dish. I bolted the dish onto an old speaker tripod
i found in my bitsnbobs shed...
I then got the missis to make it all look pretty lol
and cover the cantenna with black shiny paper and add
the mac logo (kept her happy for hours)

You dont have to attach the Cantenna to a Dish
The Cantenna will work very well without, but the dish
adds abit more D.B to the mix..
Although both ways , the Cantenna is very directional..
Luckily for me I live in a 2nd Floor Flat on a Estate
and I'm pretty high up with a good line of sight from my
living room window so I dont have to go out and get cold
to test the Sat-Cantenna.
Using my laptop i first scanned for networks using the
default internal Prism card with built in aerial.
I then connected the Cantenna to a PCMCIA D-Link network
card which we modified so that an external antenna can be
attached using reversed sma plug..
As you can see from the 2 comparisons the Cantenna easily
outperformed the internal antenna by miles :)
It even outperformed a 5db Omni Magnetic Aerial I purchased
from off the net.. HERE is a good one i recently purchased (200mw output)
The internal Network Card only picked up my own network (MacUK)
whereas the Cantenna picked up at least 8 seperate networks from
my front window alone and also another three from the back window.
The Cantenna is very directional and is best used outdoors with
good line of sight (which I have from my wondow) for optimul use.
Although this wasnt an exact percise test it shown that the Cantenna
is a 'easy' and 'cheap' way of making a 'very good' performing antenna
for any wireless network scanning....

 
The Finished Cantenna Satellite Mounted (which i,ve now named the MacTenna)
 
 

A word of warning for anyone who is setting up a wireless network or has a wireless setup..
When using security it's advisable NOT to use WEP. WEP is very unsecure and with a Linux setup and abit of software
installed it can be cracked very easily. Most BT homehumbs and routers come pre-installed with WEP 64 bit encryption,
this takes about 6 minutes to crack and 128 bit and about 30 minutes. And once your password is found someone can then
take control of your Router and cause some damage and use your internet free of charge and if you have any shared files,
these can alos be accessed, so be warned..
WPA however is much more secure, its advised that you use a password not an obvious one that maybe in the dictionary as
a dictionary attack can also be done to reveal a password.
My advise is to use WPA and also 'mac filtering' to be sure, with a long password consisting of both Letters & Numbers & if
possible turn off the radio broadcasting....
Although it is illegal to hijack or log into someone's network without the owners permission the Network owner is also
liable if any illegal activities are found to be used on the network..
So be safe - BE SECURE !!!

 
I take no credit in the original instructions to making the Cantenna.
I found the guidelines doing research's on Google and got the plugs n leads
from a repitable network dealers in the UK ( http://www.solwise.co.uk/ )
My missis does take credit for the design though :)