I am out on a road trip right now and occasionally use a USB mobile broadband modem to connect to the internet (CLEAR 4G+ Mobile USB Series S). Thing is, my wife is traveling with me and wants internet on her laptop as well. I was too cheap to buy one of the mobile hot spot devices and I also wanted flexibility to use 3G internet when 4G was not available (which is most of the time out on the road).
Turns out windows makes it is incredibly easy to share a single connection from a USB mobile internet devices (no router required). The following instructions are for windows Vista, I assume this will be similar in other versions of windows as well. First you need to do is set up a “ad hoc” network. You can do this by clicking on the start button > “connect to” then select “Set up a wireless ad hoc (computer-to-computer) network and follow the wizard.
When I was trying to share the connection while using 4G at the end of the wizard there was an option to enable “Internet Connection Sharing” after selecting this we were able to connect to with the other laptop to the newly created wireless network and surf the web… no problems.
However, when trying to connect with the 3G there was no option to enable internet connection sharing at the end of the wizard (like there was for the 4G) and it was a bit more involed to get the connection sharing to work. (Looks like this may be due to the fact that the 3G is considered a dial up connection??). This is how I did it. First create the ad hoc network as described above using the wizard, then after the network is created go to Start > Connect To > Open Network sharing center > Manage network Connections. From here you have to do two things.
Enable sharing for the connection you would like to share (for me it shows up as 3G under Dial-up). To do this right click > properties > Sharing Tab > Allow others network users to connect through this computer’s internet connection. (Also, you may have to select the individual services you would like to share – I selected them all)
Change the IP address for the ad hoc connection you just created. To do this right click the ad hoc connection in “Manage network Connections” and select properties. Next select the “Internet Protocol Version 4 (TCP/IPv4)” and click the properties button. Select the “use the following IP address” and set the IP address and Subnet mast to the following and hit ok(After changing this you may need to restart the 3G connection).
IP address: 192.168.0.1
Subnet mask: 255.255.255.0
Now just connect to the ad hoc network from your other laptop and and voila… you have shared your 3G connection and should be able to browse the web (albeit very slowly).
When you want to re-connect to a normal WiFi connection you may have to go back to manage network connections right click > properties on the network you are trying to connect to and change the “Internet Protocol Version 4 (TCP/IPv4)” connection property back to ‘Obtain IP address automatically’
Hope this helps