connecting to free public wifi hotspots

Discussion in 'General Discussion' started by bjandthebear, Sep 27, 2007.

  1. bjandthebear

    bjandthebear LI Guru Member

    I would appreciate information on or how to get to information about connecting to wifi hotspots. Lets say someone has a wireless us robotics router that mulitple laptops are hooked up to in the house and they are currently hooked to a cable modem for the internet access. Lets also say this person wanted to also be able to get internet from the free public wifi hotspots a few miles from the house. The person built a biquad dish mount antenna and bought a wrt54gl and changed the firmware in it to dd-wrt version 23sp2 vpn. The goal would be to find out how to hook the biquad antenna up to the wrt54gl and how to configure it to use this antenna to send and recieve the internet signal. And figure out if the signal strength needed to be adjusted. Then hook the wrt54gl into the usrobotics router for the security and to transmit the signal to the laptops. Does the wrt54gl need to be set up as an access point? If so would that locate wireless signals from other routers or hotspots? Or would you have to load kismet to do this? I need more information on how to make this work. Thanks in advance.
  2. ifican

    ifican Network Guru Member

    Well first a disclaimer, depending on where you live it can be considered a crime to use without asking someone else's internet whether its open (unsecured) or not. Now that being what it is i would first figure out if you can send and recieve over that distance, it is doable, once that is done getting the rest to work is a breeze.
  3. bjandthebear

    bjandthebear LI Guru Member

    Yeah I hear you. The antenna in question was tested and able to go up to 8.5 miles. Could you provide me with or lead me to the information needed to get this set up?
  4. ifican

    ifican Network Guru Member

    There really isnt much to it, you aquire a capable antenna with the right adapter so you can connect it to your router. You make sure you have 3rd party software on it so you can choose which antenna you want to send and receive from, and you aim your antenna at the target location. If you can see the signal at that point youll be good to go, set the router to wireless client mode and it should connect. If you can get that working the rest is just like setting up your home network except youll have to be wired to the router.
  5. bjandthebear

    bjandthebear LI Guru Member

    I shure would appreciate it if you could supply me with more in depth details or tell me how to find them. Step by step instructions would be great. As you probably have noticed from my questions I don't know what I am doing.
  6. ifican

    ifican Network Guru Member

    I dont know of any detailed way, its all hit and miss. I suppose if you had a gps unit you could mark the site then go back to your home and aim in that direction. Anyone that has done it just aims the antenna in the general direction and makes minute adjustments to see if the signal goes up and down.
  7. bjandthebear

    bjandthebear LI Guru Member

    I understand that. What I am confused about is setting up the wrt54gl that I have the dd-wrt installed on. You said to set it up in wireless client mode, how do I do that exactly? Once it's set up for wireless client mode will I be able to go to my laptop and search available networks through the wrt54gl?
  8. ifican

    ifican Network Guru Member

    This is by memory so it could be off but one of the option on the main setup page for the wan port, should have the ability to use dhcp, static, repeater, wierless client etc. I would choose wireless client, if you are going to be connecting to another device. I also believe in dd-wrt you can scan for networks (but not 100% sure on this one). If you have the ssid of the remote network you can plug it in at that time and point it in the general direction and see if it connects. Once you can get the wrt connected making your laptop or any other device work is just a matter of plugging it in.
  9. leenar

    leenar LI Guru Member

    The easiest way to achieve this without making modifications on the free hotspot side is to setup your WRT54G as a repeater. It will pick and repeat the hotspot signal at that point you can chose to apply WEP or WPA protection for your own signal distribution if necessary.

    There will be a drop in speed which is just what happens with repeaters. However if the signal is good you may not notice the difference unless you're downloading/uploading large files.

    DD-WRT is very simple to setup as a repeater and biquad/dish combo is a killer antenna system. One thing that you need to watch on the WRT54G side is diversity problem when using two different antennas. This may be a significant issue when using a directional antenna, the one that will cause very sketchy performance.

    There is a good article on that here. There also excellent tuts on setting up the repeater, antennas and other WRT54G hack issues.

    In the nutshell this is the issue. Diversity is a system whereby two antennas switch real fast to help with something called "multipath distortion." Propagating microwaves bounce of hard surfaces (as in buildings). The portion of the wave that was reflected of a surface will arrive to the receiver a little later than the portion that went straight from transmitter to receiver antenna. This delay can confuse the wireless router. It's like an echo.

    To fix this routers like WRT54G use two antennas. Only one is turned on at any given time. The antenna that's on is the one that has a better reception of the signal at the moment.

    So if you have a sat dish antenna plugged in one antenna port and use the other rubber ducky antenna that comes with WRT54G the diversity circutry gets real confused. You are trying to listen in on two completely separate radio cells and this is not what diversity mode is built for.

    DD-WRT allows you to turn off one antenna and that can in some cases solve the problem. There are some other solutions to this issue at the link up there.
  10. danix71

    danix71 LI Guru Member

    Excellent article above ! I just want to add one more link to explain multipath. Sorry for intromission.

    Tomato too.
  11. bjandthebear

    bjandthebear LI Guru Member


    thanks for the information. This should really help me. Sorry I didn't reply sooner but I was in the mountains and just returned to civilization.
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